Sample records for plasma initiation produced

  1. HEIGHTS initial simulation of discharge produced plasma hydrodynamics and radiation

    E-print Network

    Harilal, S. S.

    HEIGHTS initial simulation of discharge produced plasma hydrodynamics and radiation transport are taken into ac- count. The developed models are integrated into the HEIGHTS-EUV computer simulation Engineers. [DOI: 10.1117/1.1631445] Subject terms: Discharge-produced plasma; HEIGHTS-EUV; magnetohydrody

  2. HEIGHTS Initial Simulation of Discharge Produced Plasma Hydrodynamics and Radiation Transport for EUV Lithography

    E-print Network

    Harilal, S. S.

    HEIGHTS Initial Simulation of Discharge Produced Plasma Hydrodynamics and Radiation Transport. The developed models are integrated into the HEIGHTS-EUV computer simulation package. Preliminary results conditions. Keywords: Discharge-produced plasma, HEIGHTS-EUV, MHD, radiation transport, numerical simulation

  3. Breakdown voltages for discharges initiated from plasma pulses produced by high-frequency excimer lasers

    SciTech Connect

    Yamaura, Michiteru [Department of Electrical and Electronic Engineering, Faculty of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan)

    2006-06-19

    The triggering ability under the different electric field was investigated using a KrF excimer laser with a high repetition rate of kilohertz order. Measurements were made of the magnitude of impulse voltages that were required to initiate a discharge from plasmas produced by a high-frequency excimer laser. Breakdown voltages were found to be reduced by 50% through the production of plasmas in the discharge gap by a high-frequency excimer laser. However, under direct-current electric field, triggering ability decreased drastically due to low plasma density. It is considered that such laser operation applied for laser-triggered lightning due to the produced location of plasma channel is formed under the impulse electric field since an electric field of the location drastically reduces temporary when the downward leader from thunderclouds propagates to the plasma channel.

  4. Fusion reactions initiated by laser-accelerated particle beams in a laser-produced plasma

    E-print Network

    C. Labaune; C. Baccou; S. Depierreux; C. Goyon; G. Loisel; V. Yahia; J. Rafelski

    2013-10-08

    The advent of high-intensity pulsed laser technology enables the generation of extreme states of matter under conditions that are far from thermal equilibrium. This in turn could enable different approaches to generating energy from nuclear fusion. Relaxing the equilibrium requirement could widen the range of isotopes used in fusion fuels permitting cleaner and less hazardous reactions that do not produce high energy neutrons. Here we propose and implement a means to drive fusion reactions between protons and boron-11 nuclei, by colliding a laser-accelerated proton beam with a laser-generated boron plasma. We report proton-boron reaction rates that are orders of magnitude higher than those reported previously. Beyond fusion, our approach demonstrates a new means for exploring low-energy nuclear reactions such as those that occur in astrophysical plasmas and related environments.

  5. Laser-produced annular plasmas

    Microsoft Academic Search

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

    2006-01-01

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

  6. Gas lens laser produced plasma.

    PubMed

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

    1989-07-01

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

  7. ECRH Produced Plasma for Materials Processing

    NASA Astrophysics Data System (ADS)

    Rosenthal, Glenn; Cheung, P.; Wuerker, R. F.; Wong, A. Y.

    1999-11-01

    A device is being constructed to produce high density quiet plasmas for materials processing. The device consists of a solenoid magnetic field of strength up to 10 kG, and a 1.2 m long vacuum system. The plasma is produced by ECRH at either 10 GHz, or 18 GHz, with the resonance zone located on one end of the device. Plasma can be made from any gas simply by flowing the gas though the resonant zone, however, an alternative plasma production method is to sputter source material from a plate. This can be done by placing a biased plate near the ECRH resonant zone and accelerating ions from the resonant zone that will in tern impact the sputter plate and release more neutrals that will become ionized. Using this technique it is possible to produce purely metallic plasmas from several different materials. These plasmas can be used for materials processing, and have applications in the semi-conductor industry. Diagnostics include electrostatic probes, energy analyzers, LIF, and deposition measurements. The device is also equipped with an ICRH drive that can be used to change the pitch-angle of the plasma ions.

  8. Hydrodynamics of UV Laser-Produced Plasma

    Microsoft Academic Search

    Ying Yin Tsui

    1992-01-01

    Energy balance, plasma temperature, ablation parameters and asymptotic behavior of ions are measured for plasma produced by laser beams at wavelengths of 0.25 mum and 0.69 mum and pulse lengths of 1 ns to 25 ns with irradiances of 10 ^{10}-10^{14 } W\\/cm^2. The results are consistent with inverse bremsstrahlung being the dominant absorption process. Energy balance and temperature intensity

  9. Characterization of a laser plasma produced from a graphite target

    NASA Astrophysics Data System (ADS)

    Ruiz, M.; Guzmn, F.; Favre, M.; Hevia, S.; Correa, N.; Bhuyan, H.; Wynham, E. S.; Chuaqui, H.

    2014-05-01

    In order to improve the understanding of pulsed laser deposition (PLD) of diamondlike carbon (DLC) films, we have initiated a detailed study of the plasma dynamics of laser produced carbon plasmas. The carbon plasma is produced by focusing a Nd:YAG laser pulse, 380 mJ, 4 ns at 1.06 ?m, onto a graphite target, at a background pressure of 0.3 mTorr. Time resolved optical emission spectroscopic (OES) observations of the carbon plasma plume are obtained, with time and space resolution, using a SpectraPro 275 spectrograph, with a 15 ns MCP gated OMA. Line emission from CII to CIV carbon ions is identified at different stages of the plasma evolution. Line intensity ratios of successive ionization stages, CIII/CIV, was used to estimate the electron temperature throughout the Saha-Boltzmann equation, under the assumption of local thermodynamic equilibrium (LTE), and Stark broadening of CII lines was used to obtain measurements of the electron density. Characteristic plasma parameters, short after plasma formation, are 3.0 eV and 2-1017 cm-3which after 60 ns of plasma expansion decay to 2.7 eV and 510 cm-3, respectively.

  10. Laser-produced plasmas in medicine

    NASA Astrophysics Data System (ADS)

    Gitomer, Steven J.; Jones, Roger D.

    1990-06-01

    The laser has found numerous applications in medicine, beginning with uses in ophthalmology in the 1960's. Today, lasers are used in tissue cutting, blood coagulation, photo-dynamic cancer therapy, arterial plaque removal, dental drilling, etc. In this paper, we examine those areas of laser medicine in which plasmas (ionized gases) are produced. In fact, the presence of a plasma is essential for the application at hand to succeed. We consider examples of the plasmas produced in ophthalmology (e.g. lens membrane destruction following cataract surgery), in urology and gastroenterology (e.g. kidney and gall stone ablation and fragmentation) and in cardiology and vascular surgery (e.g. laser ablation and removal of fibro-fatty and calcified arterial plaque). Experimental data are presented along with some results from computer simulations of the phenomena. Comments on future directions in these areas are included.

  11. Coronal hydrodynamics of laser-produced plasmas.

    PubMed

    Aliverdiev, A; Batani, D; Dezulian, R; Vinci, T; Benuzzi-Mounaix, A; Koenig, M; Malka, V

    2008-10-01

    We present the results of an experimental investigation of the temporal evolution of plasmas produced by high power laser irradiation of various types of target materials (at intensities I(L) < or = 10(14) W/cm2). We obtained interferometric data on the evolution of the plasma profile, which can directly be compared to analytical models and numerical simulations. For aluminum and plastic targets, the agreement with 1D simulations done with the hydrocode MULTI is excellent, at least for large times (t > or = 400 ps) . In this case, simulations also show that the effect of radiation transport is negligible. The situation is quite different for gold targets for which, in order to get a fair agreement, radiation transport must be taken into account. PMID:18999540

  12. Laser produced plasma light source for EUVL

    NASA Astrophysics Data System (ADS)

    Fomenkov, Igor V.; Ershov, Alex I.; Partlo, William N.; Myers, David W.; Brown, Daniel; Sandstrom, Richard L.; La Fontaine, Bruno; Bykanov, Alexander N.; Vaschenko, Georgiy O.; Khodykin, Oleh V.; Bwering, Norbert R.; Das, Palash; Fleurov, Vladimir B.; Zhang, Kevin; Srivastava, Shailendra N.; Ahmad, Imtiaz; Rajyaguru, Chirag; De Dea, Silvia; Hou, Richard R.; Dunstan, Wayne J.; Baumgart, Peter; Ishihara, Toshihiko; Simmons, Rod D.; Jacques, Robert N.; Bergstedt, Robert A.; Brandt, David C.

    2011-04-01

    This paper describes the development of laser-produced-plasma (LPP) extreme-ultraviolet (EUV) source architecture for advanced lithography applications in high volume manufacturing. EUV lithography is expected to succeed 193 nm immersion technology for sub-22 nm critical layer patterning. In this paper we discuss the most recent results from high qualification testing of sources in production. Subsystem performance will be shown including collector protection, out-of-band (OOB) radiation measurements, and intermediate-focus (IF) protection as well as experience in system use. This presentation reviews the experimental results obtained on systems with a focus on the topics most critical for an HVM source.

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

    E-print Network

    Merlino, Robert L.

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

  14. ccsd00001732, Development behavior of liquid plasma produced by

    E-print Network

    Jun Yamada #3; and Norio Tsuda Dept. Electronics, Aichi Institute of Technology, 1247 Yakusa camera. The liquid plasma develops backward. The plasma is produced from many seeds and It consists from many seeds, which is produced by the fundamental wave. On the other hand, the plasma produced

  15. Initial Results from the Magnetized Dusty Plasma Experiment (MDPX)

    NASA Astrophysics Data System (ADS)

    Thomas, Edward; Konopka, Uwe; Lynch, Brian; Adams, Stephen; Leblanc, Spencer; Artis, Darrick; Dubois, Ami; Merlino, Robert; Rosenberg, Marlene

    2014-10-01

    The MDPX device is envisioned as a flexible, multi-user, research instrument that can perform a wide range of studies in fundamental and applied plasma physics. The MDPX device consists of two main components. The first is a four-coil, open bore, superconducting magnet system that is designed to produce uniform magnetic fields of up to 4 Tesla and non-uniform magnetic fields with gradients up to up to 2 T/m configurations. Within the warm bore of the magnet is placed an octagonal vacuum chamber that has a 46 cm outer diameter and is 22 cm tall. The primary missions of the MDPX device are to: (1) investigate the structural, thermal, charging, and collective properties of a plasma as the electrons, ions, and finally charged microparticles become magnetized; (2) study the evolution of a dusty plasma containing magnetic particles (paramagnetic, super-paramagnetic, or ferromagnetic particles) in the presence of uniform and non-uniform magnetic fields; and, (3) explore the fundamental properties of strongly magnetized plasmas (``i.e., dust-free'' plasmas). This presentation will summarize the initial characterization of the magnetic field structure, initial plasma parameter measurements, and the development of in-situ and optical diagnostics. This work is supported by funding from the NSF and the DOE.

  16. Currents and shear Alfvn wave radiation generated by an exploding laser-produced plasma: Perpendicular incidence

    Microsoft Academic Search

    M. Vanzeeland; W. Gekelman; S. Vincena; J. Maggs

    2003-01-01

    Examples of one plasma expanding into another and the consequent radiation of wave energy are abundant in both nature and the laboratory. This work is an experimental study of the expansion of a dense laser-produced plasma (initially, nlpp\\/n0>>1) into a magnetized background plasma (n0=21012 cm-3) capable of supporting Alfvn waves. The experiments are carried out on the upgraded Large Plasma

  17. Magnetic reconnection between colliding magnetized laser-produced plasma plumes.

    PubMed

    Fiksel, G; Fox, W; Bhattacharjee, A; Barnak, D H; Chang, P-Y; Germaschewski, K; Hu, S X; Nilson, P M

    2014-09-01

    Observations of magnetic reconnection between colliding plumes of magnetized laser-produced plasma are presented. Two counterpropagating plasma flows are created by irradiating oppositely placed plastic (CH) targets with 1.8-kJ, 2-ns laser beams on the Omega EP Laser System. The interaction region between the plumes is prefilled with a low-density background plasma and magnetized by an externally applied magnetic field, imposed perpendicular to the plasma flow, and initialized with an X-type null point geometry with B=0 at the midplane and B=8??T at the targets. The counterflowing plumes sweep up and compress the background plasma and the magnetic field into a pair of magnetized ribbons, which collide, stagnate, and reconnect at the midplane, allowing the first detailed observations of a stretched current sheet in laser-driven reconnection experiments. The dynamics of current sheet formation are in good agreement with first-principles particle-in-cell simulations that model the experiments. PMID:25238366

  18. A laboratory produced extremely large beta plasma

    NASA Astrophysics Data System (ADS)

    Banerjee, S. P.; Anitha, V. P.; Ravi, G.; Mattoo, S. K.

    2006-09-01

    This paper discusses laboratory production of an extremely large-beta (?103) plasma, termed ELB plasma, over an extended volume of 0.5m3. The plasma ? can be varied from <1 to values as large as 103, thereby allowing us to study physical processes through a large range of ?. Desired ? values are achieved by tailoring the ambient magnetic field by compensating fields over time scales far less than the plasma confinement time. We observe that during this compensation, the magnetic field penetration from the wall to the plasma occurs at Whistler speed. The Whistler mode is accompanied by excitation of electrostatic ion wave. We have shown that the diamagnetism of the ELB plasma is considerably modified essentially through the effect of finiteness of electron Larmor radius (rLe) in the force equilibrium. Application of these results to the space plasma is pointed out.

  19. Plasma dynamics in a discharge produced by a pulsed dual frequency inductively coupled plasma source

    SciTech Connect

    Mishra, Anurag; Lee, Sehan [Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Yeom, Geun Y., E-mail: gyyeom@skku.edu [Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746, South Korea and SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

    2014-11-01

    Using a Langmuir probe, time resolved measurements of plasma parameters were carried out in a discharge produced by a pulsed dual frequency inductively coupled plasma source. The discharge was sustained in an argon gas environment at a pressure of 10 mTorr. The low frequency (P{sub 2} {sub MHz}) was pulsed at 1 kHz and a duty ratio of 50%, while high frequency (P{sub 13.56} {sub MHz}) was maintained in the CW mode. All measurements were carried out at the center of the discharge and 20?mm above the substrate. The results show that, at a particular condition (P{sub 2} {sub MHz}?=?200 W and P{sub 13.56} {sub MHz?}=?600 W), plasma density increases with time and stabilizes at up to ?200 ?s after the initiation of P{sub 2} {sub MHz} pulse at a plasma density of (2??10{sup 17} m{sup ?3}) for the remaining duration of pulse on. This stabilization time for plasma density increases with increasing P{sub 2} {sub MHz} and becomes ?300 ?s when P{sub 2} {sub MHz} is 600 W; however, the growth rate of plasma density is almost independent of P{sub 2} {sub MHz}. Interestingly, the plasma density sharply increases as the pulse is switched off and reaches a peak value in ?10 ?s, then decreases for the remaining pulse off-time. This phenomenon is thought to be due to the sheath modulation during the transition from pulse on to pulse off and partly due to RF noise during the transition period. The magnitude of peak plasma density in off time increases with increasing P{sub 2} {sub MHz}. The plasma potential and electron temperature decrease as the pulse develops and shows similar behavior to that of the plasma density when the pulse is switched off.

  20. Microwave produced plasma in a Toroidal Device

    NASA Astrophysics Data System (ADS)

    Singh, A. K.; Edwards, W. F.; Held, E. D.

    2010-11-01

    A currentless toroidal plasma device exhibits a large range of interesting basic plasma physics phenomena. Such a device is not in equilibrium in a strict magneto hydrodynamic sense. There are many sources of free energy in the form of gradients in plasma density, temperature, the background magnetic field and the curvature of the magnetic field. These free energy sources excite waves and instabilities which have been the focus of studies in several devices in last two decades. A full understanding of these simple plasmas is far from complete. At Utah State University we have recently designed and installed a microwave plasma generation system on a small tokamak borrowed from the University of Saskatchewan, Saskatoon, Canada. Microwaves are generated at 2.45 GHz in a pulsed dc mode using a magnetron from a commercial kitchen microwave oven. The device is equipped with horizontal and vertical magnetic fields and a transformer to impose a toroidal electric field for current drive. Plasmas can be obtained over a wide range of pressure with and without magnetic fields. We present some preliminary measurements of plasma density and potential profiles. Measurements of plasma temperature at different operating conditions are also presented.

  1. Microwave-induced plasma process for producing tungsten carbide

    SciTech Connect

    Church, R.; Salsman, J.B.; Hamner, B.J.

    1991-01-01

    The operation of the invention is based upon the utilization of the heat from a microwave-induced plasma (MIP) on the following reaction: W + C + heat yields W C. Inside a microwave waveguide, a plasma chamber was constructed. The plasma chamber was filled with a gas such as helium, argon, carbon monoxide, nitrogen, carbon dioxide, etc. Elemental tungsten and carbon powders were placed inside the chamber. The plasma was produced by passing an electric field through the gas in the chamber with a voltage potential high enough to overcome the ionization potential of that gas. Once the gas was ionized the electric plasma was created. The electric field that ionizes the gas was produced by the microwave generator, thus creating a MIP. Because of the construction of the plasma chamber, the plasma totally envelopes the material, thus heating the sample uniformly.

  2. Light source employing laser-produced plasma

    DOEpatents

    Tao, Yezheng; Tillack, Mark S

    2013-09-17

    A system and a method of generating radiation and/or particle emissions are disclosed. In at least some embodiments, the system includes at least one laser source that generates a first pulse and a second pulse in temporal succession, and a target, where the target (or at least a portion the target) becomes a plasma upon being exposed to the first pulse. The plasma expand after the exposure to the first pulse, the expanded plasma is then exposed to the second pulse, and at least one of a radiation emission and a particle emission occurs after the exposure to the second pulse. In at least some embodiments, the target is a solid piece of material, and/or a time period between the first and second pulses is less than 1 microsecond (e.g., 840 ns).

  3. Laser-produced plasmas interaction with high pulsed magnetic field

    NASA Astrophysics Data System (ADS)

    Wolowski, J.; Kasperczuk, A.; Parys, P.; Pisarczyk, T.; Woryna, E.; Zakharov, Yu P.

    1999-03-01

    This work presents results of two experiments accomplished at the Institute of Plasma Physics and Laser Microfusion (IPPLM) in Warsaw: (1) investigations of the influence of magnetic field on a laser-produced plasma in the presence or absence of the background plasma, (2) investigations of dynamics of laser-produced plasma in a strong magnetic field. The aim of experiment 1 (performed in collaboration with the Institute of Laser Physics (ILP) RAS, Novosibirsk, Russia) was laboratory simulation of depolarization and deflection of plasma streams drifting across magnetic field in geoplasma background. An Nd:glass laser (5 ns, 2 J) was used to produce the plasma inside Helmholtz coils 0741-3335/41/3A/069/img9. The diagnostics for studying the interaction processes were: ion collectors, Langmuir and magnetic probes and an image converter camera. We present a comparison of the effects investigated in that experiment with some phenomena occurring in the geoplasma. In experiment 2 the plasma was produced by means of a Nd:glass laser (1 ns, 10 J) focused on a solid target located in a single-turn coil 0741-3335/41/3A/069/img10. Plasma expansion was investigated with an automated interferometer along the magnetic field lines and perpendicular to these lines. From the interferograms, it has been revealed that the plasma stream has a clear asymmetry for 0741-3335/41/3A/069/img11 caused by an unmagnetized ion Rayleigh-Taylor instability.

  4. Plasma calorimeter for absorption measurement of laser produced plasma

    SciTech Connect

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

    1985-10-01

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

  5. Observation of Plasma Satellite Lines in Laser Produced Plasmas

    Microsoft Academic Search

    D. Riley; O. Willi

    1995-01-01

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

  6. Laser-produced plasma-wall interaction O. RENNER,1

    E-print Network

    Liska, Richard

    Laser-produced plasma-wall interaction O. RENNER,1 R. LISKA,2 AND F.B. ROSMEJ3,4 1 Institute, France (RECEIVED 30 August 2009; ACCEPTED 21 September 2009) Abstract Jets of laser­generated plasma surfaces (walls). The pilot experiments carried out on the iodine laser system (5­200 J, 0.44 mm, 0

  7. Laboratory laser-produced astrophysical-like plasmas

    NASA Astrophysics Data System (ADS)

    Ripin, B. H.; Manka, C. K.; Peyser, T. A.; McLean, E. A.; Stamper, J. A.

    1990-03-01

    Laser-produced plasmas have many properties similar to, or which can be scaled to, those encountered in space, magnetospheric, ionospheric, and astrophysical situations. Several such experiments performed with the Pharos III Nd-laser facility at NRL are described.

  8. Characteristics of argon plasma waveguide produced by alumina capillary discharge for short wavelength laser application

    NASA Astrophysics Data System (ADS)

    Higashiguchi, Takeshi; Bobrova, Nadezhda; Sasorov, Pavel; Sakai, Shohei; Sentoku, Yasuhiko; Kodama, Ryosuke; Yugami, Noboru

    2012-05-01

    We have reported the argon (Ar) plasma waveguide produced in an alumina (Al2O3) capillary discharge and used to guide ultrashort laser pulses at intensities of the order of 1016 W/cm2. The electron density in the plasma waveguide was measured to be 11018 cm-3, in agreement with one-dimensional magnetrohydrodynamic (MHD) simulations. The MHD code was also used to evaluate the degree of ionization of argon (Ar) in the preformed plasma waveguide. The maximum ion charge state of Ar3+ in capillary discharge was measured and obtained in the MHD simulations. The spectrum of the propagated laser pulse in the Ar plasma waveguide was not modified and was well reproduced by a particle-in-cell simulations under initial ion charge state of Ar3+ in the preformed plasma waveguide. The optimum timing for the laser pulse injection was around 150 ns after initiation of a discharge with a peak current of 200 A.

  9. Intense terahertz emission from atomic cluster plasma produced by intense femtosecond laser pulses

    SciTech Connect

    Jahangiri, Fazel; Hashida, Masaki; Tokita, Shigeki; Sakabe, Shuji [Advanced Research Center for Beam Science, ICR, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan and Department of Physics, GSS, Kyoto University, Kitashirakawa, Sakyo, Kyoto 606-7501 (Japan); Nagashima, Takeshi; Hangyo, Masanori [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2011-12-26

    Terahertz (THz) emission from argon cluster plasma, generated by intense femtosecond laser pulses in the energy range of 10-70 mJ, has been investigated. THz polarization, energy dependence, and angular distribution were measured to provide an initial discussion on the mechanisms of THz emission. THz pulses of much higher energy were generated from argon clusters than from argon gas, which indicates that plasma produced from atomic clusters holds considerable promise as an intense THz source.

  10. New method to produce an annular cylindrical plasma for imploding plasma experiments

    SciTech Connect

    Gazaix, M.; Doucet, H.J.; Etlicher, B.; Furtlehner, J.P.; Lamain, H.; Rouille, C.

    1984-12-01

    We present a new method to produce a hollow cylindrical metallic plasma. A metallic foil is exploded by discharging a capacitor bank; the vapor which is produced expands through an annular diaphragm and forms a cylindrical shell of weakly ionized gas, which can be imploded to produce a hot, dense plasma, resulting in a high-power soft x-ray pulse. The density of the hollow cylindrical plasma is measured by resonant interferometry, a new and powerful diagnostic for probing the plasma mass density before the compression (neutral density approx. =10/sup 16/ cm/sup -3/). Our device is complementary to supersonic gas-puff or exploding wires experiments.

  11. Plasma waves near Saturn: initial results from Voyager 1

    Microsoft Academic Search

    D. A. Gurnett; W. S. Kurth; F. L. Scarf

    1981-01-01

    The Voyager 1 encounter with Saturn provided the first opportunity to investigate plasma wave interactions in the magnetosphere of Saturn. An overview of the principal results from the Voyager 1 plasma wave instrument is presented starting with the initial detection of Saturn and ending about four weeks after closest approach. A survey plot of the electric field intensities detected during

  12. Operation of an auto-initiated pulsed plasma thruster

    Microsoft Academic Search

    Abhijit Kushari; Kelvin Loh

    2010-01-01

    Purpose The purpose of this paper is to develop and characterize a pulsed plasma thruster (PPT) that does not need a spark plug to initiate the plasma discharge. Design\\/methodology\\/approach Two parallel rail thrusters were built and their performances were characterized inside a vacuum chamber to elucidate the effect of vacuum level and thruster geometry on the performance. The

  13. Collisional coupling in counterstreaming laser-produced plasmas

    NASA Technical Reports Server (NTRS)

    Koopman, D. W.; Goforth, R. R.

    1974-01-01

    The collisional processes which transfer momentum between counterstreaming plasmas are reviewed and applied to the example of a laser-produced plasma expanding into a partially ionized background. Experimental measurements of the dependence of the ion flow field on collisional momentum transfer demonstrate the validity of the simplified treatment of collision processes which have been adopted. A numerical model which simulates the laser-plasma interaction with the background confirms the importance of collisions in previous experimental studies of momentum coupling, and provides some insight into the distinction between collisional and collisionless flow regimes.

  14. Initial Cassini Plasma Observations at Saturn

    Microsoft Academic Search

    D. T. Young; F. J. Crary; J. L. Burch; R. Goldstein; D. J. McComas; J. D. Furman; C. Zinsmeyer; J.-J. Berthelier; J.-M. Illiano; M. Blanc; S. Maurice; E. Pallier; S. Bolton; A. J. Coates; D. R. Linder; H. McAndrews; A. Rymer; M. Grande; T. W. Hill; R. E. Johnson; R. A. Baragiola; H. T. Smith; V. Kelha; C. Holmlund; K. Mursala; P. Tanskanen; J. Vilppola; E. C. Sittler; D. Glen; S. Bakshi; K. R. Svenes; B. T. Narheim; K. Szego; Z. Bebesi; M. F. Thomsen; B. L. Barraclough; D. Delapp; R. L. Tokar; J. Steinberg; J. E. Nordholt; D. Reisenfeld

    2004-01-01

    The Cassini Plasma Spectrometer (CAPS) measures ion energy and mass composition from 1 eV to 50 keV and electron energy from 1 eV to 28 keV. It thus fills in important gaps in earlier Voyager measurements of energy and, in particular, ion composition. We give an overview of data taken during the first two Cassini orbits, including an overflight of

  15. Experimental Investigation of Short Scalelength Density Fluctuations in Laser-Produced Plasmas

    SciTech Connect

    Moody, J.D.; MacGowan, B.J.; Glenzer, S.H.; Kirkwood, R.K.; Kruer, W.L.; Williams, E.A.; Stone, G.F.; Montgomery, D.S.; Schmitt, A.J.

    1999-11-01

    The technique of near forward laser. scattering is used to infer characteristics of intrinsic and controlled density fluctuations in laser-produced plasmas. Intrinsic fluctuations are studied in long scalelength plasmas where the fluctuations exhibit scale sizes related to the size of the intensity variations in the plasma forming and interaction beams. Stimulated Brillouin forward scattering and filamentation appear to be the primary mechanism through which these fluctuations originate. The beam spray which results from these fluctuations is important to understand since it can affect symmetry in an inertial confinement fusion (ICF) experiment. Controlled fluctuations are studied in foam and exploding foil targets. Forward scattered light from foam targets shows evidence that the initial target inhomogeneities remain after the target is laser heated. Forward scattered light from an exploding foil plasma shows that a regular intensity pattern can be used to produce a spatially correlated density fluctuation pattern. These results provide data which can be used to benchmark numerical models of beam spray.

  16. Interaction of plasma clouds produced from two laser targets

    SciTech Connect

    Annenkov, V. I.; Bessarab, A. V.; Bondarenko, G. A.; Dolgoleva, G. V.; Zhmailo, V. A.; Krotov, V. A.; Kovalenko, V. P.; Kunin, A. V.; Nikitin, I. N.; Novikiova, E. A.; Panov, A. I.; Sobolev, I. V.; Sokolov, S. S.; Starodubtsev, V. A.; Sungatullin, R. R.; Shirokov, A. E. [All-Russia Research Institute of Experimental Physics, Russian Federal Nuclear Center (Russian Federation)

    2007-05-15

    Results are presented from studies of the interaction of two plasma clouds produced from two different-type laser targets in an ambient gas in the MKV-4 stand of the Iskra-5 facility. The experimental data are compared with the results of numerical simulations.

  17. Characterization of short pulse laser-produced plasmas

    Microsoft Academic Search

    R. Shepherd; D. Price; W. White; S. Gordan; Al. Osterheld; R. Walling; W. Goldstein; R. Stewart

    1994-01-01

    The K-shell emission from porous aluminum targets is used to infer the density and temperature of plasmas created with 800 and 400 nm, 140 fsec laser light. The laser beam is focused to a minimum spot size of 5 micrometers with 800 nm light and 3 micrometers with 400 nm light, producing a normal incidence peak intensity of 10(exp 18)

  18. Study and modelling of a RF plasma producing analogues of Titan's aerosols

    NASA Astrophysics Data System (ADS)

    Szopa, C.; Cernogora, G.; Pintassilgo, C. D.; Cavarroc, M.; Boufendi, L.; Loureiro, J.

    The aerosols of the Titan's atmosphere are produced in the Titan's stratosphere by photochemical reactions induced by the solar photons. The Cassini Huygens mission has provided for the first time in situ observations and measurements in the Titan's atmosphere. For instance, reflectance of the Titan's haze or Titan surface have to be compared with models including optical properties of the solid aerosols. As none in situ measurements of these optical properties have been done, the production and study of analogues of the Titan's aerosols (named tholins) is a good mean to estimate their properties and way of formation. Until today, the more efficient laboratory techniques to produce tholins are low pressure cold plasma discharges. In plasmas the chemistry is induced by electron collisions rather than photon processes, but the energy range of the cold plasma electrons is in the same order than the solar photons energy. In this paper, we present results obtained in a RF plasma discharge, running at low pressure in a N2/CH4 mixture representative of the Titan's atmosphere conditions. The RF plasma is produced with a capacitively coupled discharge, confined in a metallic cylindrical cage, fitted with optical apertures. The plasma is studied using Optical Emission Spectroscopy (OES) of the molecular nitrogen and radical bands emitted from the UV up to the near IR range. The bands intensities are measured as a function of plasma conditions, i.e pressure, gas mixing ratio, gas flow rate and RF absorbed power. The electron density is measured using a resonant cavity when ion densities are measured using an electrostatic probe. These techniques are used in the field of low pressure plasma diagnostics. Produced solid aerosols are collected for ex situ analysis to determine their elemental composition, their morphology. The aim of this work is to correlate the plasma conditions with the composition and physical properties of the produced tholins. From OES and electric measurements it is not possible to deduce all the plasma properties without a numerical modelling of the plasma. As a first step in the plasma modelling, the Electron Energy Distribution Function (EEDF) is calculated in a DC case under the same experimental conditions of pressure, electronic density and the initial gas mixing ratio. The EEDF is obtained by solving the Boltzmann equation coupled to a system of kinetic master equations for the most important ionic and neutral species produced in the plasma. From these calculations we 1 have an insight into the main chemical and physical processes that occur in a N2/CH4 gas mixture, which is essential for the interpretation our experimental results, as well as for the understanding of Titan's atmosphere. 2

  19. Microwave plasma initiation mechanisms in a circular tube with a radius below the cutoff value

    Microsoft Academic Search

    S. Bhattacharjee; H. Amemiya; Y. Yano

    2001-01-01

    Summary form only given, as follows. The mechanisms of microwave plasma initiation by short-pulse, high-power microwaves launched into a circular tube with a radius below the cutoff value is investigated for waves of dominant waveguide modes. The mechanism is based upon the fact that the wave of a finite amplitude penetrates into the tube and produces an electric field large

  20. Soft x-ray output a laser-produced plasma

    NASA Astrophysics Data System (ADS)

    Elton, R. C.; Grun, J.; Billings, D.-M.; Young, F. C.; Ripin, B. H.; Burris, H. R.; Resnick, J.; Ripin, D. J.

    1994-02-01

    X-rays in the 0.5-1.6 keV photon energy range, useful for debris-free damage testing of optical components, are produced efficiently by a laser-produced plasma. Energies exceeding 1 kJ in three beams from the Naval Research Laboratory (NRL) Pharos III laser irradiate a copper target to produce L-shell x-rays from plasma ions. A near-isotropic x-ray fluence of typically 5 cal/sq cm at 1 cm from the source is deduced from measurements with filtered Si-PIN and biplanar vacuum diodes. The corresponding conversion efficiency of laser to x-ray energy is typically 11%.

  1. Evolution of FMS and Alfven waves produced by the initial disturbance in the FMS waveguide

    NASA Astrophysics Data System (ADS)

    Dmitrienko, I. S.; Dmitrienko

    2013-02-01

    A description of the evolution of the initial disturbance in the fast magnetosonic (FMS) waveguide in transversely inhomogeneous plasma, given a weak coupling between FMS and Alfven modes, is made. It is shown that the Fourier transform of the FMS waveguide disturbance with respect to the coordinates along which plasma is homogeneous can be presented as a superposition of collective modes of the leading approximation with respect to the weak FMS-Alfven wave coupling from the initial instant of time. Frequencies of such collective modes and dependence of their structures on the coordinate along the inhomogeneity are found without taking the FMS-Alfven resonance into consideration, and the mode decrements are calculated using the perturbation technique. On the basis of such a representation of the FMS waveguide disturbance, the evolution of Alfven waves generating with waveguide mode packets produced by the initial disturbance of an arbitrary longitudinal structure is described. It is shown that the longitudinal structure of the Alfven disturbance generated by the collective mode packet is determined by the ratio between longitudinal scales of the initial disturbance and scales specified by resonance conditions (the resonance longitudinal wave number and the width of the range of the resonance longitudinal wave numbers). The structures of Alfven disturbances for the cases of such different ratios are described.

  2. Electron energy distribution produced by beam-plasma discharge

    NASA Technical Reports Server (NTRS)

    Anderson, H. R.; Gordeuk, J.; Jost, R. J.

    1982-01-01

    In an investigation of a beam-plasma discharge (BPD), the electron energy distribution of an electron beam moving through a partially ionized gas is analyzed. Among other results, it is found that the occurrence of BPD heats the initially cold electron beam from the accelerator. The directional intensity of electrons measured outside the beam core indicates that most particles suffer a single scattering in energy and pitch angle. At low currents this result is expected as beam particles collide with the neutral atmosphere, while in BPD the majority of particles is determined to still undergo a single scattering near the original beam core. The extended energy spectra at various beam currents show two rather distinct plasma populations, one centered at the initial beam energy (approximately 1500 eV) and the other at approximately 150 eV.

  3. Measurements of Electron Density Profiles of Plasmas Produced by Nike KrF Laser for Laser Plasma Instability (LPI) Research

    NASA Astrophysics Data System (ADS)

    Oh, Jaechul; Weaver, J. L.; Obenschain, S. P.; Schmitt, A. J.; Kehne, D. M.; Karasik, M.; Chan, L.-Y.; Serlin, V.; Phillips, L.

    2013-10-01

    Knowing spatial profiles of electron density (ne) in the underdense coronal region (n plasma is essential to understanding LPI initiation in inertial confinement fusion research. In the recent Nike LPI experiment, a side-on grid imaging refractometer (GIR) was deployed for measuring the underdense plasma profiles. Plasmas were produced from flat CH targets illuminated by Nike KrF laser with total energies up to 1 kJ of 0.5 ~ 1 nsec FWHM pulses. The GIR resolved ne up to 3 1021 /cm3 in space taking 2D snapshot images of probe laser (? = 263 nm, ?t = 10 ps) beamlets (50 ?m spacing) refracted by the plasma at a selected time during the laser illumination. The individual beamlet transmittances were also measured for Te estimation. Time-resolved spectrometers with an absolute-intensity-calibrated photodiode array and a streak camera simultaneously detected light emission from the plasma in spectral ranges relevant to Raman (SRS) and two plasmon decay instabilities. The measured spatial profiles are compared with simulation results from the FAST3D radiation hydrocode and their effects on the LPI observations are investigated. Knowing spatial profiles of electron density (ne) in the underdense coronal region (n plasma is essential to understanding LPI initiation in inertial confinement fusion research. In the recent Nike LPI experiment, a side-on grid imaging refractometer (GIR) was deployed for measuring the underdense plasma profiles. Plasmas were produced from flat CH targets illuminated by Nike KrF laser with total energies up to 1 kJ of 0.5 ~ 1 nsec FWHM pulses. The GIR resolved ne up to 3 1021 /cm3 in space taking 2D snapshot images of probe laser (? = 263 nm, ?t = 10 ps) beamlets (50 ?m spacing) refracted by the plasma at a selected time during the laser illumination. The individual beamlet transmittances were also measured for Te estimation. Time-resolved spectrometers with an absolute-intensity-calibrated photodiode array and a streak camera simultaneously detected light emission from the plasma in spectral ranges relevant to Raman (SRS) and two plasmon decay instabilities. The measured spatial profiles are compared with simulation results from the FAST3D radiation hydrocode and their effects on the LPI observations are investigated. Work supported by DoE/NNSA and performed at Naval Research Laboratory.

  4. Design of a Microwave-Initiated Pulsed Plasma Thruster Jian F. Li, Class of 2006

    E-print Network

    Choueiri, Edgar

    Design of a Microwave-Initiated Pulsed Plasma Thruster (MiPPT) Jian F. Li, Class of 2006 Submitted of a Microwave-Initiated Pulsed Plasma Thruster (MiPPT) i ABSTRACT The performance of gas-fed pulsed plasma microwave discharges as an plasma initiation source in GFPPTs. The purpose of this project is to design

  5. Ion Flux Characterization of H2 and D2 Plasmas Produced by an ECR Plasma Source

    NASA Astrophysics Data System (ADS)

    Kaiser, Eric; Capece, Angela; Roszell, John; Skinner, Charles; Koel, Bruce

    2013-10-01

    The use of lithium-conditioned plasma facing components in tokamaks has been shown to improve plasma confinement through a reduction in hydrogen recycling. Surface science techniques are being applied to probe the interactions between lithiated PFC's and H/D plasmas. A TectraTM Gen 2 plasma source has been commissioned that utilizes electron cyclotron resonance to produce a plasma discharge inside a vacuum test chamber and can produce ion fluxes similar to those typically seen in tokamaks. This source will be utilized to study H/D uptake by lithium films on Mo substrates as a precursor to NSTX-U experiments. In this work we report on the characterization of this source as a first step in its use in surface analysis studies. The source is operated in H2 and D2 gases and the subsequent ion flux of the plasma is measured by a Faraday Cup. Ion flux measurements are presented in a range of gas pressures and grid voltages up to 2 kV. The use of lithium-conditioned plasma facing components in tokamaks has been shown to improve plasma confinement through a reduction in hydrogen recycling. Surface science techniques are being applied to probe the interactions between lithiated PFC's and H/D plasmas. A TectraTM Gen 2 plasma source has been commissioned that utilizes electron cyclotron resonance to produce a plasma discharge inside a vacuum test chamber and can produce ion fluxes similar to those typically seen in tokamaks. This source will be utilized to study H/D uptake by lithium films on Mo substrates as a precursor to NSTX-U experiments. In this work we report on the characterization of this source as a first step in its use in surface analysis studies. The source is operated in H2 and D2 gases and the subsequent ion flux of the plasma is measured by a Faraday Cup. Ion flux measurements are presented in a range of gas pressures and grid voltages up to 2 kV. Science Undergraduate Laboratory Internship funded by Department of Energy.

  6. Characteristics of argon plasma waveguide produced by alumina capillary discharge for short wavelength laser application

    SciTech Connect

    Higashiguchi, Takeshi; Yugami, Noboru [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Bobrova, Nadezhda; Sasorov, Pavel [Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya Str. 25, 117218 Moscow (Russian Federation); Sakai, Shohei [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Sentoku, Yasuhiko [Department of Physics, University of Nevada, Mail Stop 220, Reno, Nevada 89506 (United States); Kodama, Ryosuke [Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Graduate School of Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2012-05-01

    We have reported the argon (Ar) plasma waveguide produced in an alumina (Al{sub 2}O{sub 3}) capillary discharge and used to guide ultrashort laser pulses at intensities of the order of 10{sup 16} W/cm{sup 2}. The electron density in the plasma waveguide was measured to be 1x10{sup 18} cm{sup -3}, in agreement with one-dimensional magnetrohydrodynamic (MHD) simulations. The MHD code was also used to evaluate the degree of ionization of argon (Ar) in the preformed plasma waveguide. The maximum ion charge state of Ar{sup 3+} in capillary discharge was measured and obtained in the MHD simulations. The spectrum of the propagated laser pulse in the Ar plasma waveguide was not modified and was well reproduced by a particle-in-cell simulations under initial ion charge state of Ar{sup 3+} in the preformed plasma waveguide. The optimum timing for the laser pulse injection was around 150 ns after initiation of a discharge with a peak current of 200 A.

  7. Fast magnetic reconnection in laser-produced plasma bubbles.

    PubMed

    Fox, W; Bhattacharjee, A; Germaschewski, K

    2011-05-27

    Recent experiments have observed magnetic reconnection in high-energy-density, laser-produced plasma bubbles, with reconnection rates observed to be much higher than can be explained by classical theory. Based on fully kinetic particle simulations we find that fast reconnection in these strongly driven systems can be explained by magnetic flux pileup at the shoulder of the current sheet and subsequent fast reconnection via two-fluid, collisionless mechanisms. In the strong drive regime with two-fluid effects, we find that the ultimate reconnection time is insensitive to the nominal system Alfvn time. PMID:21699307

  8. On a characteristic initial value problem in Plasma physics

    E-print Network

    Simone Calogero

    2005-06-01

    The relativistic Vlasov-Maxwell system of plasma physics is considered with initial data on a past light cone. This characteristic initial value problem arises in a natural way as a mathematical framework to study the existence of solutions isolated from incoming radiation. Various consequences of the mass-energy conservation and of the absence of incoming radiation condition are first derived assuming the existence of global smooth solutions. In the spherically symmetric case, the existence of a unique classical solution in the future of the initial cone follows by arguments similar to the case of initial data at time $t=0$. The total mass-energy of spherically symmetric solutions equals the (properly defined) mass-energy on backward and forward light cones.

  9. Observation and numerical analysis of plasma parameters in a capillary discharge-produced plasma channel waveguide

    SciTech Connect

    Terauchi, Hiromitsu [Department of Advanced Interdisciplinary Sciences, and Center for Optical Research and Education (CORE) Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Bobrova, Nadezhda; Sasorov, Pavel [Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya str. 25, 117259 Moscow (Russian Federation); Kikuchi, Takashi; Sasaki, Toru [Department of Electrical Engineering, Nagaoka University of Technology, Kami-tomiokamachi 1603-1, Nagaoka, Niigata 940-2188 Japan (Japan); Higashiguchi, Takeshi; Yugami, Noboru [Department of Advanced Interdisciplinary Sciences, and Center for Optical Research and Education (CORE) Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Kodama, Ryosuke [Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Graduate School of Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2011-03-01

    We observed the parameters of the discharge-produced plasma in cylindrical capillary. Plasma parameters of the waveguide were investigated by use of both a Normarski laser interferometer and a hydrogen plasma line spectrum. A space-averaged maximum temperature of 3.3 eV with electron densities of the order of 10{sup 17} cm{sup -3} was observed at a discharge time of 150 ns and a maximum discharge current of 200 A. One-dimensional dissipative magnetohydrodynamic (MHD) code was used to analyze the discharge dynamics in the gas-filled capillary discharge waveguide for high-intensity laser pulses. Simulations were performed for the conditions of the experiment. We compared the temporal behavior of the electron temperature and the radial electron density profiles, measured in the experiment with the results of the numerical simulations. They occurred to be in a good agreement. An ultrashort, intense laser pulse was guided by use of this plasma channel.

  10. Saturation of Langmuir waves in laser-produced plasmas

    SciTech Connect

    Baker, K.L.

    1996-04-01

    This dissertation deals with the interaction of an intense laser with a plasma (a quasineutral collection of electrons and ions). During this interaction, the laser drives large-amplitude waves through a class of processes known as parametric instabilities. Several such instabilities drive one type of wave, the Langmuir wave, which involves oscillations of the electrons relative to the nearly-stationary ions. There are a number of mechanisms which limit the amplitude to which Langmuir waves grow. In this dissertation, these mechanisms are examined to identify qualitative features which might be observed in experiments and/or simulations. In addition, a number of experiments are proposed to specifically look for particular saturation mechanisms. In a plasma, a Langmuir wave can decay into an electromagnetic wave and an ion wave. This parametric instability is proposed as a source for electromagnetic emission near half of the incident laser frequency observed from laser-produced plasmas. This interpretation is shown to be consistent with existing experimental data and it is found that one of the previous mechanisms used to explain such emission is not. The scattering version of the electromagnetic decay instability is shown to provide an enhanced noise source of electromagnetic waves near the frequency of the incident laser.

  11. Electron temperature and average density in spherical laser-produced plasmas - Ultraviolet plasma spectroscopy

    NASA Technical Reports Server (NTRS)

    Goldsmith, S.; Seely, J. F.; Feldman, U.; Behring, W. E.; Cohen, L.

    1985-01-01

    The average values of the electron temperature Te and the electron density Ne in the corona plasmas of spherically irradiated high-Z targets have been estimated. Targets composed of the elements Cu through Br, Rb, and Mo were irradiated using the fundamental (1.06 microns) and the frequency-tripled (351 nm) output of the Omega laser system. Spectra were recorded in the wavelength region 15-200 A. Using various extreme ultraviolet spectroscopic techniques, it is found that for the case of a Mo plasma produced by frequency-tripled laser irradiation, Te = 2600 + or - 600 eV and Ne is greater than 6 x 10 to the 20th/cu cm. This is consistent with a 'flux limit' smaller than 0.1. The estimated values of Te and Ne are lower in the corona plasmas produced using the fundamental (1.06 micron) irradiation.

  12. Recent Science Education Initiatives at the Princeton Plasma Physics Laboratory

    NASA Astrophysics Data System (ADS)

    Zwicker, Andrew; Dominguez, Arturo; Gershman, Sophia; Guilbert, Nick; Merali, Aliya; Ortiz, Deedee

    2013-10-01

    An integrated approach to program development and implementation has significantly enhanced a variety of Science Education initiatives for students and teachers. This approach involves combining the efforts of PPPL scientists, educators, research and education fellows, and collaborating non-profit organizations to provide meaningful educational experiences for students and teachers. Our undergraduate internship program continues to have outstanding success, with 72% of our participants going to graduate school and 45% concentrating in plasma physics. New partnerships have allowed us to increase the number of underrepresented students participating in mentored research opportunities. The number of participants in our Young Women's Conference increases significantly each year. Our Plasma Camp workshop, now in its 15th year, recruits outstanding teachers from around the country to create new plasma-centered curricula. Student research in the Science Education Laboratory concentrates on the development of a high-fidelity plasma speaker, a particle dropper for a dusty plasma experiment, microplasmas along liquid surfaces for a variety of applications, an Internet-controlled DC glow discharge source for students, and a Planeterrella for demonstrating the aurora and other space weather phenomenon for the general public.

  13. Detection of electromagnetic pulses produced by hypervelocity micro particle impact plasmas

    NASA Astrophysics Data System (ADS)

    Close, Sigrid; Linscott, Ivan; Lee, Nicolas; Johnson, Theresa; Strauss, David; Goel, Ashish; Fletcher, Alexander; Lauben, David; Srama, Ralf; Mocker, Anna; Bugiel, Sebastian

    2013-09-01

    Hypervelocity micro particles (mass < 1 ng), including meteoroids and space debris, routinely impact spacecraft and produce plasmas that are initially dense (1028 m-3), but rapidly expand into the surrounding vacuum. We report the detection of radio frequency (RF) emission associated with electromagnetic pulses (EMPs) from hypervelocity impacts of micro particles in ground-based experiments using micro particles that are 15 orders of magnitude less massive than previously observed. The EMP production is a stochastic process that is influenced by plasma turbulence such that the EMP detection rate that is strongly dependent on impact speed and on the electrical charge conditions at the impact surface. In particular, impacts of the fastest micro particles occurring under spacecraft charging conditions representative of high geomagnetic activity are the most likely to produce RF emission. This new phenomenon may provide a source for unexplained RF measurements on spacecraft charged to high potentials.

  14. Detection of electromagnetic pulses produced by hypervelocity micro particle impact plasmas

    SciTech Connect

    Close, Sigrid; Lee, Nicolas; Johnson, Theresa; Goel, Ashish; Fletcher, Alexander [Department of Aeronautics and Astronautics, Stanford University, Stanford, California 94305 (United States)] [Department of Aeronautics and Astronautics, Stanford University, Stanford, California 94305 (United States); Linscott, Ivan; Strauss, David; Lauben, David [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)] [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Srama, Ralf; Mocker, Anna; Bugiel, Sebastian [Institut fr Raumfahrtsysteme, Universitt Stuttgart, Pfaffenwaldring 29, 70569 Stuttgart (Germany)] [Institut fr Raumfahrtsysteme, Universitt Stuttgart, Pfaffenwaldring 29, 70569 Stuttgart (Germany)

    2013-09-15

    Hypervelocity micro particles (mass < 1 ng), including meteoroids and space debris, routinely impact spacecraft and produce plasmas that are initially dense (?10{sup 28} m{sup ?3}), but rapidly expand into the surrounding vacuum. We report the detection of radio frequency (RF) emission associated with electromagnetic pulses (EMPs) from hypervelocity impacts of micro particles in ground-based experiments using micro particles that are 15 orders of magnitude less massive than previously observed. The EMP production is a stochastic process that is influenced by plasma turbulence such that the EMP detection rate that is strongly dependent on impact speed and on the electrical charge conditions at the impact surface. In particular, impacts of the fastest micro particles occurring under spacecraft charging conditions representative of high geomagnetic activity are the most likely to produce RF emission. This new phenomenon may provide a source for unexplained RF measurements on spacecraft charged to high potentials.

  15. Plasma waves near Saturn: Initial results from Voyager 1

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.; Kurth, W. S.; Scarf, F. L.

    1981-01-01

    The Voyager 1 encounter with Saturn provided the first opportunity to investigate plasma wave interactions in the magnetosphere of Saturn. An overview of the principal results from the Voyager 1 plasma wave instrument is presented starting with the initial detection of Saturn and ending about four weeks after closest approach. A survey plot of the electric field intensities detected during the Saturn encounter is shown starting shortly before the inbound shock crossing and ending shortly after the outbound magnetopause crossing. Many intense waves were observed in the vicinity of Saturn. To provide a framework for presenting the observations, the results are discussed more or less according to the sequence in which the data were obtained.

  16. Experimental investigation of short scalelength density fluctuations in laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Moody, J. D.; MacGowan, B. J.; Glenzer, S. H.; Kirkwood, R. K.; Kruer, W. L.; Montgomery, D. S.; Schmitt, A. J.; Williams, E. A.; Stone, G. F.

    2000-05-01

    The technique of near forward laser scattering is used to infer characteristics of intrinsic and controlled density fluctuations in laser-produced plasmas. Intrinsic fluctuations are studied in long-scalelength plasmas where it is found that the fluctuations exhibit scale sizes related to the intensity variation scales in the plasma forming and interaction beams. Stimulated Brillouin forward scattering and filamentation appear to be the primary mechanism through which these fluctuations originate. The beam spray resulting from these fluctuations is important to understand, since it can affect symmetry in an inertial confinement fusion (ICF) experiment. Controlled fluctuations are studied in foam and exploding foil targets. Forward scattered light from foam targets shows evidence that the initial target inhomogeneities remain after the target is laser heated. Forward scattered light from an exploding foil plasma shows that a regular intensity pattern can be used to produce a spatially correlated density fluctuation pattern. These results provide data which are being used to benchmark numerical models of beam spray.

  17. Experimental Investigation of Short Scalelength Density Fluctuations in Laser-Produced Plasmas

    SciTech Connect

    Moody, J.D.; MacGowan, B.J.; Glenzer, S.H.; Kirkwood, R.K.; Kruer, W.L.; Montgomery, D.S.; Schmitt, A.J.; Williams, E.A.; Stone, G.F.

    2000-01-05

    The technique of near forward laser scattering is used to infer characteristics of intrinsic and controlled density fluctuations in laser-produced plasmas. Intrinsic fluctuations are studied in long-scale length plasmas where we find that the fluctuations exhibit scale sizes related to the intensity variation scales in the plasma-forming and interaction beams. Stimulated Brillouin forward scattering and filamentation appear to be the primary mechanism through which these fluctuations originate. The beam spray resulting from these fluctuations is important to understand since it can affect symmetry in an inertial confinement fusion (ICF) experiment. Controlled fluctuations are studied in foam and exploding foil targets. Forward scattered light from foam targets shows evidence that the initial target inhomogeneities remain after the target is laser heated. Forward scattered light from an exploding foil plasma shows that a regular intensity pattern can be used to produce a spatially correlated density fluctuation pattern. These results provide data which are being used to benchmark numerical models of beam spray.

  18. Molten metal analysis by laser produced plasmas. Technical progress report

    SciTech Connect

    Kim, Yong W.

    1994-02-01

    A new method of molten metal analysis, based on time- and space-resolved spectroscopy of a laser-produced plasma (LPP) plume of a molten metal surface, has been implemented in the form of a prototype LPP sensor-probe, allowing in-situ analysis in less than 1 minute. The research at Lehigh University has been structured in 3 phases: laboratory verification of concept, comparison of LPP method with conventional analysis of solid specimens and field trials of prototype sensor-probe in small-scale metal shops, and design/production/installation of two sensor-probes in metal production shops. Accomplishments in the first 2 phases are reported. 6 tabs, 3 figs.

  19. Plasma Characteristics of the Discharge Produced during Mechanoluminescence

    SciTech Connect

    Eddingsaas, Nathan C.; Suslick, Kenneth S. [School of Chemical Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

    2007-12-07

    The conditions during light emission from the fracture of solids have been difficult to determine because such mechanoluminescence (ML) is usually weak. When ML is produced by acoustic cavitation of a liquid slurry of resorcinol crystals, however, we observe bright light emission, which makes it possible to measure plasma conditions by emission spectra: a bimodal heavy atom emission temperature profile is observed with 405{+-}22 K (for 80% of emitting CH) and 4015{+-}730 K (for 20%), with an electron density and energy of 1.3{+-}0.13x10{sup 14} cm{sup -3} and {approx}3.5 eV (i.e., an effective T{sub e}{approx}41 000 K)

  20. Suprathermal electron transport in laser-produced plasmas

    SciTech Connect

    Mason, R.J.

    1981-01-01

    A self-consistent, collisional, particle-in-cell scheme has been developed to model the one dimensional transport of suprathermal electrons in laser produced plasmas. This full Monte Carlo approach was taken, since earlier, simpler models have failed to explain an experimentally almost universal anomalous inhibition of thermal transport. The Monte Carlo scheme allows for free-streaming, ion scatter, and self thermalization of the electrons, which are moved in self-consistent E-fields computed with the aid of implicit fluid moments. PIC hydrodynamics for the ions, ponderomotive forces, and resonance and inverse-bremsstrahlung absorption of the light are all accommodated. In application to the anomalous inhibition problem, use of the scheme demonstrates that intrinsic differences in the Monte Carlo, and conventional flux-limited diffusion modelling of the transport results in apparent and real inhibition, explaining the need for strong flux-limiting in the simpler diffusion modelling of experiments.

  1. Evidence of plasma polarization shift of Ti He-? resonance line in high density laser produced plasmas

    NASA Astrophysics Data System (ADS)

    Khattak, F. Y.; Percie du Sert, O. A. M. B.; Rosmej, F. B.; Riley, D.

    2012-12-01

    A spectroscopic study of the He-? (1s2 1s0 - ls2p 1p1) line emission (4749.73 eV) from high density plasma was conducted. The plasma was produced by irradiating Ti targets with intense (I ? ll019 W/cm2), 400nm wavelength high contrast, short (45fs) p-polarized laser pulses at an angle of 45. A line shift up to 3.4+1.0 eV (1.90.55 m) was observed in the He-? line. The line width of the resonance line at FWHM was measured to be 12.10.6 eV (6.70.35 m). For comparison, we looked into the emission of the same spectral line from plasma produced by irradiating the same target with laser pulses of reduced intensities (?1017 W/cm2): we observed a spectral shift of only 1.8+1.0 eV (0.9+0.55m) and the line-width measures up to 5.8+0.25 eV (2.7+0.35 m). These data provide evidence of plasma polarization shift of the Ti He-? line.

  2. Initial studies of core and edge transport of NSTX plasmas

    NASA Astrophysics Data System (ADS)

    Synakowski, E. J.; Bell, M. G.; Bell, R. E.; Bush, C. E.; Bourdelle, C.; Darrow, D.; Dorland, W.; Ejiri, A.; Fredrickson, E. D.; Gates, D. A.; Kaye, S. M.; Kubota, S.; Kugel, H. W.; LeBlanc, B. P.; Maingi, R.; Maqueda, R. J.; Menard, J. E.; Mueller, D.; Rosenberg, A.; Sabbagh, S. A.; Stutman, D.; Taylor, G.; Johnson, D. W.; Kaita, R.; Ono, M.; Paoletti, F.; Peebles, W.; Peng, Y.-K. M.; Roquemore, A. L.; Skinner, C. H.; Soukhanovskii, V. A.; NSTX Research Team

    2002-05-01

    Rapidly developing diagnostic, operational, and analysis capability is enabling the first detailed local physics studies to begin in high ? plasmas of the National Spherical Torus Experiment (NSTX). These studies are motivated in part by the observation of energy confinement times in neutral-beam-heated discharges that are favourable with respect to predictions from the ITER-89P scaling expression. For plasmas heated with neutral beam injection (NBI), analysis based on profile measurements suggests that electron heat conduction is the dominant thermal loss channel. Cases where early analysis indicates that ion thermal conduction may be exceptionally low is motivating studies of possible sources of ion heating not presently accounted for by classical collisional processes. Gyrokinetic microstability studies indicate that long wavelength turbulence with k??i~0.1-1 may be stable or suppressed by EB shear in these plasmas, while modes with k??i~50 may be robust. High harmonic fast wave (HHFW) heating efficiently heats electrons on NSTX, and studies have begun using it to assess transport in the electron channel. Regarding edge transport, H-mode transitions occur with either NBI or HHFW heating. The power required for L- to H-mode transitions far exceeds that expected from empirical ELM-free H-mode scaling laws derived from moderate aspect ratio devices. Finally, initial fluctuation measurements made with two techniques are permitting the first characterizations of edge turbulence.

  3. Visible spectral power emitted from a laser produced uranium plasma

    NASA Technical Reports Server (NTRS)

    Williams, M. D.; Jalufka, N. W.

    1975-01-01

    The development of plasma-core nuclear reactors for advanced terrestrial and space-power sources is researched. Experimental measurements of the intensity and the spectral distribution of radiation from a nonfissioning uranium plasma are reported.

  4. Microwave reflections from a vacuum ultraviolet laser produced plasma sheet

    E-print Network

    Scharer, John E.

    as the plasma. A computer model is developed to interpret and optimize the plasma conditions which provide been several studies14 of a plasma as a mi- crowave reflector or absorber based on its application wave at a dielectric boundary is given by the Fresnel reflection coef- ficient, Ereflected Eincident p

  5. Particle Dynamics in Neutral-Gas Confined Laser-Produced Plasmas

    Microsoft Academic Search

    Yong W. Kim

    2001-01-01

    Laser-produced plasma from a metallic target can be confined to higher plasma densities by immersing the target in an inert gas medium at increasingly high density. The plasma becomes Rayleigh-Taylor unstable, however, when the mass density of the neutral gas exceeds the plasma mass density substantially.[1] A new plasma diagnostic method is developed to help examine the early time development

  6. Structure of an Exploding Laser-Produced Plasma

    SciTech Connect

    Collette, A.; Gekelman, W. [Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, California 90095 (United States)

    2010-11-05

    We describe the first-ever volumetric, time-resolved measurements performed with a moving probe within an expanding dense plasma, embedded in a background magnetized plasma. High-resolution probe measurements of the magnetic field and floating potential in multiple 2D cut planes combined with a 1 Hz laser system reveal complex three-dimensional current systems within the expanding plasma. Static ({omega}{sub real}=0) flutelike density striations are observed at the leading edge of the plasma, which are correlated to variations in the current layer at the edge of the expanding plasma.

  7. PREUVE and the EXULITE project: modular laser-produced plasma EUV source

    NASA Astrophysics Data System (ADS)

    Ceccotti, Tiberio; Chichmanian, F.; Descamps, D.; Haltebourg, P.; Hergott, Jean-Francois; Hulin, S.; Normand, Didier; Segers, Marc; Sublemontier, Olivier; Schmidt, Martin; Cormont, Philippe; Neu, M.; Thro, Pierre-Yves; Weulersse, Jean-Marc; Barthod, B.; Bernard, R.; Veran, E.; Barbiche, Jean-Marie; D'Aux, Ph.; Marquis, E.

    2002-09-01

    Within the PREUVE project, the GAP of CEA Saclay has developed an EUV source that should meet (alpha) -tool specifications by the end of this year. In particular, a laser-produced plasma source has been developed that uses a dense and confined xenon jet target. Our technical solution is based on a specific target injector design and the use of well adapted nozzle materials to avoid debris formation by plasma erosion. After injection, the xenon is recycled and highly purified to reach a low cost round- the-clock operation. This source provides both high conversion efficiency and low debris flux. These are necessary conditions for its industrial application in the future EUV microlithography. The conception of the so-called ELSA (EUV Lithography Source Apparatus) prototype allows in principal 2 years full operation on the French lithography test bench BEL (Banc d'essai pour la lithographie) that has been developed during PREUVE. In parallel, the EXULITE consortium that is coordinated by Alcatel Vacuum Technology France (AVTF) has started its activities in the frame of the European MEDEA+ initiative on EUV source development. In collaboration with Thales and the CEA, AVTF develops a prototype power source for EUV lithography production tools by the end of 2004. A low cost and modular high power laser system architecture has been chosen and is developed by Thales and the CEA to pump the laser plasma- produced EUV source.

  8. Laser produced plasma EUV sources for device development and HVM

    NASA Astrophysics Data System (ADS)

    Brandt, David C.; Fomenkov, Igor V.; Lercel, Michael J.; La Fontaine, Bruno M.; Myers, David W.; Brown, Daniel J.; Ershov, Alex I.; Sandstrom, Richard L.; Bykanov, Alexander N.; Vaschenko, Georgiy O.; Bwering, Norbert R.; Das, Palash; Fleurov, Vladimir B.; Zhang, Kevin; Srivastava, Shailendra N.; Ahmad, Imtiaz; Rajyaguru, Chirag; De Dea, Silvia; Dunstan, Wayne J.; Baumgart, Peter; Ishihara, Toshi; Simmons, Rod D.; Jacques, Robert N.; Bergstedt, Robert A.; Porshnev, Peter I.; Wittak, Christian J.; Woolston, Michael R.; Rafac, Robert J.; Grava, Jonathan; Schafgans, Alexander A.; Tao, Yezheng

    2012-03-01

    Laser produced plasma (LPP) systems have been developed as the primary approach for the EUV scanner light source for optical imaging of circuit features at sub-22nm and beyond nodes on the ITRS roadmap. This paper provides a review of development progress and productization status for LPP extreme-ultra-violet (EUV) sources with performance goals targeted to meet specific requirements from leading scanner manufacturers. We present the latest results on exposure power generation, collection, and clean transmission of EUV through the intermediate focus. Semiconductor industry standards for reliability and source availability data are provided. We report on measurements taken using a 5sr normal incidence collector on a production system. The lifetime of the collector mirror is a critical parameter in the development of extreme ultra-violet LPP lithography sources. Deposition of target material as well as sputtering or implantation of incident particles can reduce the reflectivity of the mirror coating during exposure. Debris mitigation techniques are used to inhibit damage from occuring, the protection results of these techniques will be shown over multi-100's of hours.

  9. Initial operation of a large-scale plasma source ion implantation experiment

    NASA Astrophysics Data System (ADS)

    Wood, B. P.; Henins, I.; Gribble, R. J.; Reass, W. A.; Faehl, R. J.; Nastasi, M. A.; Rej, D. J.

    In Plasma Source Ion Implantation (PSII), a workpiece to be implanted is immersed in a weakly ionized plasma and pulsed to a high negative voltage. Plasma ions are accelerated toward the workpiece and implanted in its surface. Experimental PSII results reported in the literature have been for small workpieces. A large scale PSII experiment has recently been assembled at Los Alamos, in which stainless steel and aluminum workpieces with surface areas over 4 sq m have been implanted in a 1.5 m-diameter, 4.6 m-length cylindrical vacuum chamber. Initial implants have been performed at 50 kV with 20 micro-s pulses of 53 A peak current, repeated at 500 Hz, although the pulse modulator will eventually supply 120 kV pulses of 60 A peak current at 2 kHz. A 1,000 W, 13.56 MHz capacitively-coupled source produces nitrogen plasma densities in the 10(exp 15) m(exp -3) range at neutral pressures as low as 0.02 mtorr. A variety of antenna configurations have been tried, with and without axial magnetic fields of up to 60 gauss. Measurements of sheath expansion, modulator voltage and current, and plasma density fill-in following a pulse are presented. The authors consider secondary electron emission, x-ray production, workpiece arcing, implant conformality, and workpiece and chamber heating.

  10. Preparation and properties of plasma-initiated graft copolymerized membranes for blood plasma separation

    NASA Astrophysics Data System (ADS)

    Onishi, M.; Shimura, K.; Seita, Y.; Yamashita, S.; Takahashi, A.; Masuoka, T.

    A hydrophilic composite membrane for blood plasma separation has been prepared by surface graft copolymerization initiated by low-temperature plasma (LTP). After short LTP pre-irradiation onto a microporous polypropylene (PP) membrane, N-N-dimethylacrylamide (DMAA) vapor was introduced for grafting. The PP membrane had a 0.45 ?m effective pore size and a 130 ?m thickness. The rate of DMAA grafting onto PP was very high, even in vapor-solid phase reaction under reduced pressure; DMAA 1 mm Hg (133Pa). The percentage of grafted poly-DMAA (PDMAA) reached 15% within 5 min post graft polymerization, and the membrane surface, including the interior surface of pores, became completely hydrophilic. There was no apparent change observed in the membrane morphology in the dry state after the PDMAA-grafted layer was formed. However, water flux significantly decreased, probably due to swelling of the PDMAA-grafted layer. With a grafting yield below 17%, the PDMAA-grafted PP (PP-g-PDMAA) membrane showed a good separation capability of plasma from whole blood. The PP-g-PDMAA membrane exhibited low complement activating potential, high sieving coefficient for plasma proteins and high blood compatibility. Decreases in adsorption of blood cells, plasma proteins, and other biomolecules may be the reason for the membrane performance.

  11. Initial experiments of RF gas plasma source for heavy ionfusion

    SciTech Connect

    Ahle, L.; Hall, R.; Molvik, A.W.; Chacon-Golcher, E.; Kwan, J.W.; Leung, K.N.; Reijonen, J.

    2002-05-22

    The Source Injector Program for the US Heavy Ion Fusion Virtual National Laboratory is currently exploring the feasibility of using RF gas plasma sources for a HIF driver. This source technology is presently the leading candidate for the multiple aperture concept, in which bright millimeter size beamlets are extracted and accelerated electrostatically up to 1 MeV before the beamlets are allowed to merge and form 1 A beams. Initial experiments have successfully demonstrated simultaneously high current density, {approx} 100 mA/cm{sup 2} and fast turn on, {approx} 1 {micro}s. These experiments were also used to explore operating ranges for pressure and RF power. Results from these experiments are presented as well as progress and plans for the next set of experiments for these sources.

  12. Initial Studies of Core and Edge Transport of NSTX Plasmas

    SciTech Connect

    E.J. Synakowski; M.G. Bell; R.E. Bell; C.E. Bush; C. Bourdelle; D. Darrow; W. Dorland; A. Ejiri; E.D. Fredrickson; D.A. Gates; S.M. Kaye; S. Kubota; H.W. Kugel; B.P. LeBlanc; R. Maingi; R.J. Maqueda; J.E. Menard; D. Mueller; A. Rosenberg; S.A. Sabbagh; D. Stutman; G. Taylor; D.W. Johnson; R. Kaita; M. Ono; F. Paoletti; W. Peebles; Y-K.M. Peng; A.L. Roquemore (a), C.H. Skinner; V.A. Soukhanovskii; and the NSTX Research Team

    2001-09-19

    Rapidly developing diagnostic, operational, and analysis capability is enabling the first detailed local physics studies to begin in high-beta plasmas of the National Spherical Torus Experiment (NSTX). These studies are motivated in part by energy confinement times in neutral-beam-heated discharges that are favorable with respect to predictions from the ITER-89P scaling expression. Analysis of heat fluxes based on profile measurements with neutral-beam injection (NBI) suggest that the ion thermal transport may be exceptionally low, and that electron thermal transport is the dominant loss channel. This analysis motivates studies of possible sources of ion heating not presently accounted for by classical collisional processes. Gyrokinetic microstability studies indicate that long wavelength turbulence with k(subscript ''theta'') rho(subscript ''i'') {approx} 0.1-1 may be suppressed in these plasmas, while modes with k(subscript ''theta'') rho(subscript ''i'') {approx} 50 may be robust. High-harmonic fast-wave (HHFW) heating efficiently heats electrons on NSTX, and studies have begun using it to assess transport in the electron channel. Regarding edge transport, H-mode [high-confinement mode] transitions occur with either NBI or HHFW heating. The power required for low-confinement mode (L-mode) to H-mode transitions far exceeds that expected from empirical edge-localized-mode-free H-mode scaling laws derived from moderate aspect ratio devices. Finally, initial fluctuation measurements made with two techniques are permitting the first characterizations of edge turbulence.

  13. Parameters of atmospheric plasmas produced by electrosurgical devices

    NASA Astrophysics Data System (ADS)

    Keidar, Michael; Shashurin, Alexey; Canady, Jerome

    2013-10-01

    Electrosurgical systems are extensively utilized in general surgery, surgical oncology, plastic and reconstructive surgery etc. In this work we study plasma parameters created by electrosurgical system SS-200E/Argon 2 of US Medical Innovations. The maximal length of the discharge plasma column at which the discharge can be sustained was determined as function of discharge power and argon flow rate. Electrical parameters including discharge current and voltage were measured. Recently proposed Rayleigh microwave scattering method for temporally resolved density measurements of small-size atmospheric plasmas was utilized. Simultaneously, evolution of plasma column was observed using intensified charge-coupled device (ICCD) camera.

  14. Four-dimensional imaging of the initial stage of fast evolving plasmas

    NASA Astrophysics Data System (ADS)

    Zhu, Pengfei; Zhang, Zhongchao; Chen, Long; Zheng, Jun; Li, Runze; Wang, Weimin; Li, Junjie; Wang, Xuan; Cao, Jianming; Qian, Dong; Sheng, Zhengming; Zhang, Jie

    2010-11-01

    Using an ultrafast electron probe capable of four-dimensional diagnosis, the initial stage of fast evolving plasmas produced by a 1014 W/cm2 laser irradiation of a metal target was investigated in real time with picosecond time resolution. The associated strong transient electric field was identified to have two components, which either focus or defocus the probe electron beam. The effects of this field on the probe electron beam can be reproduced by a self-expanding charge cloud containing about 5107 suprathermal electrons with the outermost layer expanding at an average speed of 1.2107 m/s.

  15. Numerical simulation of self-focusing in laser produced plasmas

    Microsoft Academic Search

    S. Sartang; R. G. Evans; W. T. Toner

    1983-01-01

    Numerical solutions of the wave equation in a plasma with a nonlinear index due to the ponderomotive force show self-focusing and strong aberration effects including bifurcation at high power. The same features are seen in plane and cylindrical geometry and nonuniform as well as uniform plasmas.

  16. Instability Produced by the Ion Drag Force in Dusty Plasmas

    Microsoft Academic Search

    P. K. Shukla; G. M. Morfill

    1999-01-01

    It is shown that the ion drag force acting on the charged dust grains can cause an instability of electrostatic waves in dusty plasmas. The instability can be responsible for the great void, which is observed in low-temperature dusty plasma discharges.

  17. Plasma dynamics in laboratory-produced current sheets

    SciTech Connect

    Frank, Anna G.; Kyrie, Natalya P.; Satunin, Sergey N. [A.M. Prokhorov Institute of General Physics of the Russian Academy of Sciences, 38 Vavilov Street, Moscow 119991 (Russian Federation)

    2011-11-15

    Evolution of currents and Ampere forces in current sheets are analyzed on the basis of magnetic measurements. Two new effects are observed in the current distributions at the later stage of the sheet evolution: first, a broadening of the current area at the side edges of the current sheet; second, a generation of reverse currents followed by their propagation from the edges to the center of the sheet. Super-thermal plasma flows moving across the width of the current sheet are observed by spectroscopic methods. The energies of plasma jets are consistent with the spatial structure and time dependences of the Ampere forces in the current sheets. The assumption is advanced that plasma acceleration may be more effective at the regions with lower plasma density, which are located at some distances from the sheet mid-plane. Generation of reverse currents provides an additional confirmation of transfer of energetic plasma jets toward the sheet edges.

  18. Use of multilayer targets to inject trace elements into laser-produced plasma

    SciTech Connect

    Zigler, A.; Kolbe, J.; Lee, R.W.

    1987-04-27

    The use of multilayer target with predrilled holes to inject trace elements into laser-produced plasma is presented. The tracer plasma obtained shows a smaller source size and reduced opacity compared to a plasma target. The preparation and alignment of the proposed target are extremely simple.

  19. Stimulated Scattering and Self-Focusing in Laser-Produced Plasmas

    Microsoft Academic Search

    A. J. Palmer

    1971-01-01

    Calculations are presented of the threshold conditions for the onset of stimulated scattering processes and self-focusing within a fully ionized, laser-produced, spark plasma, using a linearized theory. Plasma density fluctuations induced through ponderomotive forces and thermal deposition are found to give rise to net gains for stimulated Thomson scattering for a realizable set of values of plasma parameters and laser

  20. Space charge saturation of Faraday cup detectors used in laser-produced plasmas studies

    Microsoft Academic Search

    G. Redman; Ying Tsui; R. Fedosejevs

    2002-01-01

    Faraday cups are commonly used to measure plasma expansion characteristics in laser-produced plasmas. In its simplest design a Faraday cup consists of a grounded entrance grid and a biased collector plate. As an expanding laser plasma flows into the Faraday cup, the entrance grid, with a mesh size smaller than the local Debye screening length, separates electrons from the ions

  1. Experimental investigation of short scalelength density fluctuations in laser-produced plasmas

    Microsoft Academic Search

    J. D. Moody; B. J. MacGowan; S. H. Glenzer; R. K. Kirkwood; W. L. Kruer; D. S. Montgomery; A. J. Schmitt; E. A. Williams; G. F. Stone

    2000-01-01

    The technique of near forward laser scattering is used to infer characteristics of intrinsic and controlled density fluctuations in laser-produced plasmas. Intrinsic fluctuations are studied in long-scalelength plasmas where it is found that the fluctuations exhibit scale sizes related to the intensity variation scales in the plasma forming and interaction beams. Stimulated Brillouin forward scattering and filamentation appear to be

  2. Experimental Investigation of Short Scalelength Density Fluctuations in Laser-Produced Plasmas

    Microsoft Academic Search

    J. D. Moody; B. J. MacGowan; S. H. Glenzer; R. K. Kirkwood; W. L. Kruer; E. A. Williams; G. F. Stone; D. S. Montgomery; A. J. Schmitt

    1999-01-01

    The technique of near forward laser. scattering is used to infer characteristics of intrinsic and controlled density fluctuations in laser-produced plasmas. Intrinsic fluctuations are studied in long scalelength plasmas where the fluctuations exhibit scale sizes related to the size of the intensity variations in the plasma forming and interaction beams. Stimulated Brillouin forward scattering and filamentation appear to be the

  3. Tritium Containment in the Dust and Debris of Plasma-Facing Materials Produced During Operations

    E-print Network

    Harilal, S. S.

    ' . . , . Tritium Containment in the Dust and Debris of Plasma-Facing Materials Produced During avaihble original document. #12;Tritium Containment in the Dust and Debris of Plasma-Facing hlaterials. IL 60439, USA Tritium behavior in plasma-facing components of future tokamak reactors such as ITER

  4. Initial study of the optical spectrum of the ISIS H- ion source plasma.

    PubMed

    Lawrie, S R; Faircloth, D C; Philippe, K

    2012-02-01

    The front end test stand is being constructed at the Rutherford Appleton Laboratory, with the aim of producing a 60 mA, 2 ms, 50 Hz, perfectly chopped H(-) ion beam. To meet the beam requirements, a more detailed understanding of the ion source plasma is required. To this end, an initial study is made of the optical spectrum of the plasma using a digital spectrometer. The atomic and molecular emission lines of hydrogen and caesium are clearly distinguished and a quantitative comparison is made when the ion source is run in different conditions. The electron temperature is 0.6 eV and measured line widths vary by up to 75%. PMID:22380213

  5. Plasma produced by impacts of fast dust particles on a thin film

    NASA Technical Reports Server (NTRS)

    Auer, Siegfried

    1994-01-01

    The thin-film impact plasma detector was pioneered by Berg for detecting small cosmic dust particles and measuring their approximate velocities in a time-of-flight configuration. While Berg's device was highly successful in establishing the flux of interplanetary dust, the accuracy of measuring the velocities of individual particles was a moderate 18 percent in magnitude and 27 degrees in angle. A much greater accuracy of less than or equal to 1 percent in determining the velocity components appears desirable in order to associate a particle with its parent body. In order to meet that need, research was initiated to determine if a thin-film detector can be designed to provide such accurate velocity measurements. Previous laboratory investigations of the impact plasma uncovered two difficulties: (1) solid or liquid spray is ejected from a primary impact crater and strikes neighboring walls where it produces secondary impact craters and plasma clouds; as a result, both quantity and time of detection of the plasma can vary significantly with the experiment configuration. Particles from an accelerator rarely have speeds v greater than or equal to 10-15 km/s, while cosmic dust particles typically impact at v = 10-72 km/s. The purpose of the tests discussed in this paper was to resolve the two difficulties mentioned. That is, the experiment configuration was designed to reduce the contribution of plasma from secondary impacts. In addition, most particles with v less than or equal to 25 km/s and all particles with v less than or equal to 10 km/s were eliminated from the beam.

  6. Resolving the positive, negative, and neutral fluxes of an expanding, laser-produced plasma.

    PubMed

    Sarraf, S; Woodall, D M

    1978-08-01

    The space-charge separation seen in an expanding, laser-produced plasma is a remnant of energetic electrons produced in anomalous laser absorption. In order to better understand this phenomenon, a Faraday cup collector has been devised which simultaneously records positive, negative, and neutral components of such an expanding plasma. The response of this detector to a laser-produced plasma is measured and compared to magnetically filtered ion collectors. This detector proves superior to the magnetic collector for energetic ions, but is limited to low plasma densities by collective effects. PMID:18699270

  7. Nonlinear regime of the filamentation of a microwave produced plasma

    SciTech Connect

    Shokri, B.; Niknam, A. R. [Physics Department and Laser-Plasma Research Institute of Shahid Beheshti University, Evin, Tehran, Iran and Institute for Studies in Theoretical Physics and Mathematics, P.O. Box 19395-1795, Tehran (Iran, Islamic Republic of); Laser-Plasma Research Institute of Shahid Beheshti University, Evin, Tehran (Iran, Islamic Republic of)

    2007-03-15

    The nonlinear dynamics of the magnetic field and anisotropic instability due to interaction of a plasma with microwave radiation, by making use of magnetohydrodynamic equations and Ampere-Maxwell law, are investigated. Also, it is shown that the Lienard nonlinear differential equation describes the evolution of the magnetic field in the plasma. We investigate the profiles of magnetic field and electron density variation in plasma and show that these profiles have a nonsinusoidal shape in the nonlinear regime. Furthermore, it is shown that the electron density becomes highly peaked in this regime. Also, due to the nonlinear effect, the cross section and shape of transverse filamentation can vary in the static limit.

  8. Dynamics of C2 formation in laser-produced carbon plasma in helium environment

    E-print Network

    Harilal, S. S.

    Dynamics of C2 formation in laser-produced carbon plasma in helium environment K. F. Al-Shboul, S. S. Harilal,a) A. Hassanein, and M. Polek School of Nuclear Engineering and Center for Materials the role of helium ambient gas on the dynamics of C2 species formation in laser-produced carbon plasma

  9. Development of Plasma Electron Guns to Produce Narrow Focusing Beams Under the Higher Operation Pressure

    Microsoft Academic Search

    V. Burdovitsin; M. Eroshkin; I. Osipov; N. Rempe; I. Zhirkov; E. Oks

    2005-01-01

    Summary form only given. One of the main advantages of the plasma cathode electron guns is its ability to produce electron beam under the higher operation pressure up to fore-pump pressure range. Present work is devoted to plasma electron guns that were designed especially to generate narrow focusing electron beams under the high pressure. To produce narrow focusing beam two

  10. Persistence of uranium emission in laser-produced plasmas

    SciTech Connect

    LaHaye, N. L.; Harilal, S. S., E-mail: hari@purdue.edu; Diwakar, P. K.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2014-04-28

    Detection of uranium and other nuclear materials is of the utmost importance for nuclear safeguards and security. Optical emission spectroscopy of laser-ablated U plasmas has been presented as a stand-off, portable analytical method that can yield accurate qualitative and quantitative elemental analysis of a variety of samples. In this study, optimal laser ablation and ambient conditions are explored, as well as the spatio-temporal evolution of the plasma for spectral analysis of excited U species in a glass matrix. Various Ar pressures were explored to investigate the role that plasma collisional effects and confinement have on spectral line emission enhancement and persistence. The plasma-ambient gas interaction was also investigated using spatially resolved spectra and optical time-of-flight measurements. The results indicate that ambient conditions play a very important role in spectral emission intensity as well as the persistence of excited neutral U emission lines, influencing the appropriate spectral acquisition conditions.

  11. Initial operation of a plasma isotope separation system

    Microsoft Academic Search

    T. S. Bigelow; F. Tarallo

    2002-01-01

    Summary form only given. A plasma-based isotope separation system has been installed at TheragenicsTM Oak Ridge, TN facility and has recently been placed into operation. This facility is designed to separate stable isotopes of metallic elements utilizing the Plasma Separation Process' (PSP). In this process, electron cyclotron resonance heating using a microwave power source forms the plasma. Neutral particles of

  12. Diamond-like carbon sputtering by laser produced Xe plasma

    NASA Astrophysics Data System (ADS)

    Amano, Sho; Inoue, Tomoaki

    2013-11-01

    The sputtering of diamond-like carbon (DLC) was investigated using Xe ion bombardment from the laser plasma X-ray source (LPX). The LPX we developed uses a solid Xe target and emits UV-X-rays and Xe ions. Using the LPX as an ion source, we measured etching depths of DLC, Ru, and Au films using a quartz crystal microbalance (QCM) to determine their ion sputtering rates at incident angles of 0 and 70. The calculated results by the SRIM code were able to predict the measured results, except for the case of the DLC film at 0 incident. Our measured result indicated that the DLC sputtering at 0 was ten times larger than previously reported data, in which an ion gun was used. We consider that the difference was a characteristic effect of the laser plasma, and can be explained as a synergistic effect of ion bombardment and UV radiation from the Xe plasma.

  13. Energy loss of heavy ions in laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Roth, M.; Stckl, C.; S, W.; Iwase, O.; Gericke, D. O.; Bock, R.; Hoffmann, D. H. H.; Geissel, M.; Seelig, W.

    2000-04-01

    The unique combination of a high-energy Nd:glass laser system and the intense heavy-ion beam at Gesellschaft fr Schwerionenforschung (GSI) allowed for the first time the measurement of the stopping power of heavy ions in plasmas at the level of one percent solid-state density and temperatures of about 60 eV. Energy loss measurements of swift heavy ions (5 6 MeV/u) in a carbon plasma revealed a stopping power exceeding theoretical predictions which was not observed in earlier experiments at lower plasma densities. This discrepancy can be resolved assuming higher effective charge states of the projectiles resulting in a consistent picture for the measured parameter range.

  14. Suprathermal electrons produced by beam-plasma-discharge

    NASA Technical Reports Server (NTRS)

    Sharp, W. E.

    1982-01-01

    Experiments conducted with a low energy plasma lens, HARP, in the electron beam of the large vacuum chamber at Johnson Space Center indicate that an enhanced population of 50 to 300 volt electrons appear when the beam goes into the Beam-Plasma Discharge (BPD) mode. Below the BPD instability the electron distribution appears to be characterized as non-energized single particle scattering and energy loss. At 100 cm from the beam core in the BPD mode the fluxes parallel to the beam are reduced by a factor of 20 with respect to the fluxes at 25 cm. Some evidence for isotropy near the beam core is presented.

  15. Angular emission of ions and mass deposition from femtosecond and nanosecond laser-produced plasmas

    SciTech Connect

    Verhoff, B.; Harilal, S. S.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2012-06-15

    We investigated the angular distribution of ions and atoms emanating from femto- and nanosecond laser-produced metal plasmas under similar laser fluence conditions. For producing plasmas, aluminum targets are ablated in vacuum employing pulses from a Ti:Sapphire ultrafast laser (40 fs, 800 nm) and an Nd:YAG laser (6 ns, 1064 nm). The angular distribution of ion emission as well as the kinetic energy distribution is characterized by a Faraday cup, while a quartz microbalance is used for evaluating deposited mass. The ion and deposited mass features showed that fs laser ablated plasmas produced higher kinetic energy and more mass per pulse than ns plumes over all angles. The ion flux and kinetic energy studies show fs laser plasmas produce narrower angular distribution while ns laser plasmas provide narrower energy distribution.

  16. Magnetic inflation produced by the Mini-Magnetospheric Plasma Propulsion (M2P2) prototype

    NASA Astrophysics Data System (ADS)

    Winglee, R. M.; Ziemba, T.; Euripides, P.; Slough, J.

    2002-01-01

    Mini-Magnetospheric Plasma Propulsion (M2P2) seeks the creation of a magnetic wall or bubble (i.e. a magnetosphere) attached to a spacecraft that will intercept the solar wind and thereby provide high-speed propulsion with little expenditure of propellant. The prototype uses a helicon source embedded asymmetrically in a dipole-like magnetic field. Breakdown of the plasma can be produced at high densities 1012-1013 cm-3 with a temperature of several eV. The plasma pressure is sufficient to cause the outward expansion or inflation of the mini-magnetosphere. This expansion has now been measured directly by magnetic field probes. Computer simulations of the laboratory geometry show the presence of magnetic field perturbations that have similar magnitude and temporal variations as seen in the experiments. The field line mapping from the model has similar features to the optical images taken during laboratory prototype. The agreement between the laboratory experiments and the computer simulations provide quantitative evidence that inflation of a dipole field can be achieved in the laboratory, essentially all the way out to the chamber walls which in the large chamber experiments corresponds to several tens of magnet radii. The operation characteristics of the prototype are consistent with the initial simulations that indicated that if such a device were operated in space then it could produce a mini-magnetosphere of the order of about 15-20 km. Such a mini-magnetosphere would experience 1-3 N of thrust from the solar wind, while requiring on 1-2 kWe of power to sustain the mini-magnetosphere. .

  17. Influence of low atomic number plasma component on the formation of laser-produced plasma jets

    SciTech Connect

    Kasperczuk, A.; Pisarczyk, T.; Badziak, J.; Borodziuk, S.; Chodukowski, T. [Institute of Plasma Physics and Laser Microfusion, 23 Hery St., 00-908 Warsaw (Poland); Gus'kov, S. Yu.; Demchenko, N. N. [Institute of Plasma Physics AS CR, v.v.i., Za Slovankou 3, 182 00 Prague 8 (Czech Republic); Ullschmied, J.; Krousky, E.; Masek, K.; Pfeifer, M.; Rohlena, K.; Skala, J. [Institute of Physics AS CR, v.v.i., Na Slovance 2, 182 21 Prague 8 (Czech Republic); Pisarczyk, P. [Warsaw University of Technology, ICS, 15/19 Nowowiejska St., 00-665 Warsaw (Poland)

    2010-11-15

    The results of investigations are presented that are connected with a very simple method of plasma jet formation, which consists in irradiating a massive planar target made of material with relatively high atomic number by a partly defocused laser beam. This brief communication is aimed at investigations of interaction of axially symmetrical light (plastic-CH) plasma with heavy (copper) plasma. It demonstrates that a relatively thin plastic plasma envelope can compress the Cu plasma and control the Cu-jet formation.

  18. Multilayer refractory nozzles produced by plasma-spray process

    NASA Technical Reports Server (NTRS)

    Bliton, J. L.; Rausch, J. L.

    1966-01-01

    Multilayer rocket nozzles formed by plasma spraying have good thermal shock resistance and can be reheated in an oxidizing environment without loss of coating adherence. Suggested application of this process are for the production of refractory components, which can be formed as surfaces of revolution.

  19. Thermonuclear fusion plasma produced by CO2 laser

    Microsoft Academic Search

    H. Nishimura; H. Fujita; Y. Kawamura; N. Banjoya; H. Daido; Y. Yanase; T. Seki; K. Iba; M. Matoba; S. Nakai

    1978-01-01

    The coupling mechanism of CO2 laser with plasma has been investigated. With respect to the laser power density, three different absorption regions are observed: the classical absorption, the parametric decay instability, and the resonant absorption. The resonant absorption is clearly testified by the spatial directivity of the scattered light due to the polarization of the light. In this power density

  20. Characterisation of plasmas produced by the Torche a Injection Axiale

    Microsoft Academic Search

    J. Jonkers; L. J. M. Selen; Mullen van der JJAM; J. M. De Regt; E. A. H. Timmermans; D. C. Schram

    1996-01-01

    Summary form only given. The Torche a Injection Axiale (TIA), i.e. torch with axial gas injection, was developed by the group of Moisan in 1993. We report on the investigations on two different kind of plasmas created by the TIA: one with helium and the other with argon as main gas. Using absolute line intensity measurements the densities of the

  1. Robe Development for Electrical Conductivity Analysis in an Electron Gun Produced Helium Plasma

    NASA Technical Reports Server (NTRS)

    Bragg-Sitton, Shannon M.; Bitteker, Leo; Rodgers, Stephen L. (Technical Monitor)

    2002-01-01

    The use of magnetohydrodynamic (MHD) power conversion systems, potentially coupled with a fission power source, is currently being investigated as a driver for an advanced propulsion system, such as a plasma thruster. The efficiency of a MHD generator is strongly dependent on the electrical conductivity of the fluid that passes through the generator; power density increases as fluid conductivity increases. Although traditional MHD flows depend on thermal ionization to enhance the electrical conductivity, ionization due to nuclear interactions may achieve a comparable or improved conductivity enhancement while avoiding many of the limitations inherent to thermal ionization. Calculations suggest that nuclear-enhanced electrical conductivity increases as the neutron flux increases; conductivity of pure He-3 greater than 10 mho/m may be achievable if exposed to a flux greater than 10(exp 12) neutrons/cm2/s.) However, this remains to be demonstrated experimentally. An experimental facility has been constructed at the Propulsion Research Center at the NASA Marshall Space Flight Center, using helium as the test fluid. High energy electrons will be used to simulate the effects of neutron-induced ionization of helium gas to produce a plasma. These experiments will be focused on diagnosis of the plasma in a virtually static system; results will be applied to future tests with a MHD system. Initial experiments will utilize a 50 keV electron gun that can operate at up to a current of 200 micro A. Spreading the electron beam over a four inch diameter window results in an electron flux of 1.5x 10(exp 13) e/sq cm/s. The equivalent neutron flux that would produce the same ionization fraction in helium is 1x10(exp 12) n/sq cm/s. Experiments will simulate the neutron generated plasma modeled by Bitteker, which takes into account the products of thermal neutron absorption in He-3, and includes various ion species in estimating the conductivity of the resulting plasma. Several different probes will be designed and implemented to verify the plasma kinetics model. System parameters and estimated operating ranges are summarized. The predicted ionization fraction, electron density, and conductivity levels are provided in for an equivalent neutron flux of 1x10(exp 12) n/cm2/s. Understanding the complex plasma kinetics throughout a MHD channel is necessary to design an optimal power conversion system for space propulsion applications. The proposed experiments seek to fully characterize the helium plasma and to determine the reliability of each measurement technique, such that they may be applied to more advanced MHD studies. The expected value of each plasma parameter determined from theoretical models will be verified experimentally by several independent techniques to determine the most reliable method of obtaining each parameter. The results of these experiments will be presented in the final paper.

  2. Microwave Reflections from a VUV Laser Produced Plasma Sheet

    Microsoft Academic Search

    K. L. Kelly; J. E. Scharer; G. Ding; M. Bettenhausen; D. Sinitsyn

    1996-01-01

    A Vacuum Ultra-Violet (VUV) Laser is utilized for creation of a plasma sheet in a low-ionization-energy organic gas. Microwaves from an X-band horn antenna impinge on the sheet where they are reflected. A bi-static antenna system is used for detecting the microwave radiation. Heterodyne and homodyne detection systems are investigated. Reflected signals are measured for amplitude and phase analysis. Comparable

  3. Microwave reflections from a VUV laser produced plasma sheet

    Microsoft Academic Search

    K. L. Kelly; J. E. Scharer; W. Shen; G. Ding; M. H. Bettenhausen; N. T. Lam

    1996-01-01

    Summary form only given. A Vacuum Ultra-Violet (VUV) laser pulse is used to create a plasma sheet in a low-ionization-energy organic gas. Microwaves from a highly directive X-band horn antenna impinge on the sheet where they are reflected. A bi-static antenna system is used for transmitting and receiving the microwave radiation. Both heterodyne and homodyne detection systems are investigated for

  4. Beam heated linear theta-pinch device for producing hot plasmas

    DOEpatents

    Bohachevsky, Ihor O. (Los Alamos, NM)

    1981-01-01

    A device for producing hot plasmas comprising a single turn theta-pinch coil, a fast discharge capacitor bank connected to the coil, a fuel element disposed along the center axis of the coil, a predetermined gas disposed within the theta-pinch coil, and a high power photon, electron or ion beam generator concentrically aligned to the theta-pinch coil. Discharge of the capacitor bank generates a cylindrical plasma sheath within the theta-pinch coil which heats the outer layer of the fuel element to form a fuel element plasma layer. The beam deposits energy in either the cylindrical plasma sheath or the fuel element plasma layer to assist the implosion of the fuel element to produce a hot plasma.

  5. Plasma observations near Saturn - Initial results from Voyager 1

    Microsoft Academic Search

    H. S. Bridge; J. W. Belcher; A. J. Lazarus; S. Olbert; J. D. Sullivan; F. Bagenal; P. R. Gazis; R. E. Hartle; K. W. Ogilvie; J. D. Scudder; E. C. Sittler; A. Eviatar; G. L. Siscoe; C. K. Goertz; V. M. Vasyliunas

    1981-01-01

    The Voyager 1 encounter with Saturn and its satellites yielded extensive measurements of magnetospheric low-energy plasma electrons and positive ions, both heavy and light, probably of hydrogen and nitrogen or oxygen. At radial distances between 15 and 7 Saturn radii on the inbound trajectory, the plasma appears to corotate with a velocity within 20% of that theoretically expected for rigid

  6. Plasma observations near Neptune - Initial results from Voyager 2

    Microsoft Academic Search

    J. W. Belcher; H. S. Bridge; B. Coppi; G. S. Gordon Jr.; A. J. Lazarus; R. L. McNutt Jr.; F. Bagenal; O. Divers; A. Eviatar; K. W. Ogilvie; L. Villanueva; M. Zhang; E. C. Jr. Sittler; G. L. Siscoe; V. M. Vasyliunas

    1989-01-01

    The plasma science experiment on Voyager 2 made observations of the plasma environment in Neptune's magnetosphere and in the surrounding solar wind. Because of the large tilt of the magnetic dipole and fortuitous timing, Voyager entered Neptune's magnetosphere through the cusp region, the first cusp observations at an outer planet. Thus the transition from the magnetosheath to the magnetosphere observed

  7. Time-Resolved Electron Density Measurements of Laser Produced Plasmas using X-Band Microwave Interferometry

    Microsoft Academic Search

    K. Ellen Keister; Jeffrey L. Putney; Clark J. Wagner; J. Gary Eden

    2008-01-01

    Laser produced plasma channels form a unique and significant laboratory tool for exploring the kinetics of plasma formation and decay. Using a sub-picosecond 100 GW ultraviolet laser system and a microwave interferometer operating at 9.2 GHz, time-resolved measurements are made of the electron density of the plasma. By vacuum sealing part of the interferometer, measurements are made at pressures between

  8. Laser-produced aluminum plasma expansion inside a plastic plasma envelope

    NASA Astrophysics Data System (ADS)

    Kasperczuk, A.; Pisarczyk, T.; Chodukowski, T.; Kalinowska, Z.; Parys, P.; Renner, O.; Gus'kov, S. Yu.; Demchenko, N. N.; Ullschmied, J.; Krousky, E.; Pfeifer, M.; Rohlena, K.; Skala, J.

    2012-09-01

    Previous experimental results demonstrated that the plasma pressure decreases with the growing atomic number of the target material. In this context, a question arose if the Al plasma outflow could be collimated using the plastic plasma as a compressor. To solve this problem, an experiment using a plastic target with an Al cylindrical insert was performed. The focal spot diameter substantially larger than that of the insert ensured simultaneous heating both target materials. This experiment proved that a production of Al plasma jets collimated by an action of outer plastic plasma is feasible [Kasperczuk et al., Laser Part. Beams 30, 1 (2012)]. The results of investigations presented here provide additional information on distributions of electron temperature in the outflowing plasma and time and space characteristics of ion emission, both registered at bare and constrained-flow Al targets. The experiment was carried out at the Prague asterix laser system iodine laser facility. The laser provided a 250 ps (full width at half maximum) pulse with the energy of 130 J at the third harmonic frequency (?3 = 0.438 ?m). A plastic target with an Al cylindrical insert of 400 ?m in diameter as well as a bare Al target (for comparison) was used. The focal spot diameter (?L) 1200 ?m ensured the lateral pressure effect of the plastic plasma strong enough to guarantee the effective Al plasma compression. The electron temperature measurements have shown that such Al plasma compression is accompanied by the increase of its temperature, dominance of which starts at distance of 0.5 mm from the target surface. Measurements of ion emission characteristics confirm the earlier numerical simulation prediction that in these conditions the plasma expansion geometry is closer to planar. The constrained Al plasma jet is very narrow and its axial velocity is considerably larger than the velocity of freely expanding Al plasma stream. It means that the plastic plasma envelope, besides the Al plasma compression, also strongly accelerates the Al plasma in its axial motion.

  9. Activation of K+ Channels in the Plasma Membrane of Arabidopsis by ATP Produced Photosynthetically

    Microsoft Academic Search

    Edgar P. Spalding; Mary Helen; M. Goldsmith

    1993-01-01

    Light activates a K+ channel and transiently depolarizes the plasma membrane of Arabidopsis mesophyll cells. Geneti- cally or chemically impairing photosynthesis abolished this electrical response to light. These results indicate that illuminated chloroplasts produce a factor that activated K+ channels in the plasma membrane. By patch clamping at the single-channel levei, we have obtained evidence that ATP is one such

  10. X-ray spectroscopy application for magnetic field and electron beam measurements in laser produced plasma

    Microsoft Academic Search

    E. O. Baronova; G. Sholin

    1998-01-01

    Temperature and density gradients, parametric instabilities which are common to laser produced plasma, can lead to both spontaneous magnetic field and electron beam generation. Strong magnetic field splits lines, suprathermal electrons are of great importance in energy transition processes and in plasma emission spectra formation. The paper presents magnetic field strength and suprathermal electron energy measurement methods, based on investigation

  11. On the atomic state densities of plasmas produced by the torche injection axiale

    Microsoft Academic Search

    J. Jonkers; H. P. C. Vos; Mullen van der JJAM; E. A. H. Timmermans

    1996-01-01

    The atomic state densities of helium and argon plasmas produced by the microwave driven plasma torch called the torche injection axiale are presented. They are obtained by absolute line intensity measurements of the excited states and by applying the ideal gas law to the ground state. It will be shown that the atomic state distribution function (ASDF) does not

  12. Ballistic pendula for measuring the momentum of a laser-produced plasma

    SciTech Connect

    Grun, J.; Ripin, B.H.

    1982-12-01

    We describe the use of a ballistic pendulum array to measure the momentum of a laser-produced plasma. An in situ calibration method is described and the pendulum results are compared to measurements made with other diagnostics.

  13. Ballistic pendula for measuring the momentum of a laser-produced plasma

    SciTech Connect

    Grun, J.; Ripin, B.H.

    1982-09-17

    We describe the use of a ballistic pendulum array to measure the momentum of a laser-produced plasma. An insitu calibration method is described and the pendulum results are compared to measurements made with other diagnostics.

  14. Enhancing extreme ultraviolet photons emission in laser produced plasmas for advanced lithography

    E-print Network

    Harilal, S. S.

    Enhancing extreme ultraviolet photons emission in laser produced plasmas for advanced lithography T. Sizyuk and A. Hassanein Center for Materials under Extreme Environment, School of Nuclear Engineering sources for the next generation extreme ultraviolet lithography (EUVL) are increasing EUV power

  15. Thomson scattering measurement of a shock in laser-produced counter-streaming plasmas

    SciTech Connect

    Morita, T.; Kuramitsu, Y.; Moritaka, T. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan)] [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Sakawa, Y.; Takabe, H. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan) [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Graduate School of Science, Osaka University, 1-1 Machikane-yama, Toyonaka, Osaka 560-0043 (Japan); Tomita, K.; Nakayama, K.; Inoue, K.; Uchino, K. [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan)] [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan); Ide, T.; Tsubouchi, K. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)] [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Nishio, K.; Ide, H.; Kuwada, M. [Graduate School of Science, Osaka University, 1-1 Machikane-yama, Toyonaka, Osaka 560-0043 (Japan)] [Graduate School of Science, Osaka University, 1-1 Machikane-yama, Toyonaka, Osaka 560-0043 (Japan)

    2013-09-15

    We report the first direct measurement of temporally and spatially resolved plasma temperatures at a shock as well as its spatial structure and propagation in laser-produced counter-streaming plasmas. Two shocks are formed in counter-streaming collisionless plasmas early in time, and they propagate opposite directions. This indicates the existence of counter-streaming collisionless flows to keep exciting the shocks, even though the collisional effects increase later in time. The shock images are observed with optical diagnostics, and the upstream and downstream plasma parameters of one of the shocks are measured using Thomson scattering technique.

  16. Properties of a capillary discharge-produced argon plasma waveguide for shorter wavelength source application

    NASA Astrophysics Data System (ADS)

    Sakai, Shohei; Higashiguchi, Takeshi; Bobrova, Nadezhda; Sasorov, Pavel; Miyazawa, Jun; Yugami, Noboru; Sentoku, Yasuhiko; Kodama, Ryosuke

    2011-10-01

    We report the operation of a discharge-produced argon (Ar) plasma waveguide in an alumina (Al2O3) capillary to guide a 1016-W/cm2 ultrashort laser pulse for shorter wavelength light sources at high repetition rate operation. The electron density in the plasma channel was measured to be 1 1018 cm-3. Modeling with a one-dimensional magnetrohydrodynamic code was used to evaluate the degree of ionization of Ar in the preformed plasma channel. The observed spectrum of the laser pulse after propagation in the argon plasma waveguide was not modified and was well reproduced by a particle in cell simulation.

  17. Properties of a capillary discharge-produced argon plasma waveguide for shorter wavelength source application.

    PubMed

    Sakai, Shohei; Higashiguchi, Takeshi; Bobrova, Nadezhda; Sasorov, Pavel; Miyazawa, Jun; Yugami, Noboru; Sentoku, Yasuhiko; Kodama, Ryosuke

    2011-10-01

    We report the operation of a discharge-produced argon (Ar) plasma waveguide in an alumina (Al(2)O(3)) capillary to guide a 10(16)-W/cm(2) ultrashort laser pulse for shorter wavelength light sources at high repetition rate operation. The electron density in the plasma channel was measured to be 1 10(18) cm(-3). Modeling with a one-dimensional magnetrohydrodynamic code was used to evaluate the degree of ionization of Ar in the preformed plasma channel. The observed spectrum of the laser pulse after propagation in the argon plasma waveguide was not modified and was well reproduced by a particle in cell simulation. PMID:22047296

  18. Computational Interpretation of Megagauss-Magnetic-Field-Induced Metallic Surface Plasma Initiation and Evolution

    SciTech Connect

    Lindemuth, Irvin R.; Siemon, Richard E.; Bauer, Bruno S.; Angelova, Milena A.; Atchison, Walter L. [University of Nevada, Reno, Nevada (United States); Los Alamos National Laboratory, Los Alamos, New Mexico (United States)

    2010-11-05

    Numerical simulations of experiments in which plasma is formed on an aluminum surface by megagauss magnetic fields provide the first computational demonstration of a magnetic-field threshold that must be reached for aluminum plasma to begin to form. The computed times of plasma initiation agree reasonably well with the observations across the full range of rod diameters, leading to the conclusion that plasma formation is a thermal process. Computationally, plasma forms first in low-density material that is resistive enough to expand across the magnetic field and yet conductive enough that Ohmic heating exceeds expansion cooling.

  19. Four-dimensional imaging of the initial stage of fast evolving plasmas

    SciTech Connect

    Zhu Pengfei; Wang Weimin [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Zhang Zhongchao; Chen Long; Zheng Jun; Li Runze; Qian Dong [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Li Junjie; Wang Xuan; Cao Jianming [Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 (United States); Sheng Zhengming; Zhang Jie [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2010-11-22

    Using an ultrafast electron probe capable of four-dimensional diagnosis, the initial stage of fast evolving plasmas produced by a 10{sup 14} W/cm{sup 2} laser irradiation of a metal target was investigated in real time with picosecond time resolution. The associated strong transient electric field was identified to have two components, which either focus or defocus the probe electron beam. The effects of this field on the probe electron beam can be reproduced by a self-expanding charge cloud containing about 5x10{sup 7} suprathermal electrons with the outermost layer expanding at an average speed of 1.2x10{sup 7} m/s.

  20. Characterization of ion emission of an extreme ultraviolet generating discharge produced Sn plasma

    SciTech Connect

    Gielissen, K.; Mullen, J. J. A. M. v. d. [Eindhoven University of Technology, Den Dolech 2, 5600 MB Eindhoven (Netherlands); Sidelnikov, Y. [ISAN Institute of Spectroscopy, Fizicheskaya Str. 5, Troitsk, Moscow Region 142190 (Russian Federation); Glushkov, D.; Banine, V. [ASML, De Run 6501, 5504 DR Veldhoven (Netherlands); Soer, W. A. [Philips Research, High Tech Campus 4, 5656 AE Eindhoven (Netherlands)

    2010-01-15

    The ion emission of a Sn-based discharge produced extreme ultraviolet producing plasma is characterized with the combined use of different time-of-flight techniques. An electrostatic ion spectrometer is employed to measure the average charge distribution of the emitted Sn ions. A dedicated Faraday cup configuration is used to measure the total ion flux from the source for different discharge energies. High-energy Sn ions emitted by the plasma with energies up to 100 keV have been identified. The number of high-energy ions increases for higher electrical input energy into the plasma while the signal associated with the expanding plasma ions does not show such dependence. The ion energy distribution for a bulk of detected ions is calculated based on the Faraday cup measurements and compared with theoretical plasma expansion dynamics.

  1. Emittance of positron beams produced in intense laser plasma interaction

    NASA Astrophysics Data System (ADS)

    Chen, Hui; Sheppard, J. C.; Meyerhofer, D. D.; Hazi, A.; Link, A.; Anderson, S.; Baldis, H. A.; Fedosejev, R.; Gronberg, J.; Izumi, N.; Kerr, S.; Marley, E.; Park, J.; Tommasini, R.; Wilks, S.; Williams, G. J.

    2013-01-01

    The first measurement of the emittance of intense laser-produced positron beams has been made. The emittance values were derived through measurements of positron beam divergence and source size for different peak positron energies under various laser conditions. For one of these laser conditions, we used a one dimensional pepper-pot technique to refine the emittance value. The laser-produced positrons have a geometric emittance between 100 and 500 mm.mrad, comparable to the positron sources used at existing accelerators. With 1010-1012 positrons per bunch, this low emittance beam, which is quasi-monoenergetic in the energy range of 5-20 MeV, may be useful as an alternative positron source for future accelerators.

  2. Emittance of positron beams produced in intense laser plasma interaction

    SciTech Connect

    Chen Hui; Hazi, A.; Link, A.; Anderson, S.; Gronberg, J.; Izumi, N.; Tommasini, R.; Wilks, S. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Sheppard, J. C. [SLAC, Standford University, Menlo Park, California 94025 (United States); Meyerhofer, D. D. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Baldis, H. A.; Marley, E.; Park, J.; Williams, G. J. [Department of Electrical and Computer Engineering, University of California, Davis, California 95616 (United States); Fedosejev, R.; Kerr, S. [Department of Applied Science, University of Alberta, Alberta T6G 2R3 (Canada)

    2013-01-15

    The first measurement of the emittance of intense laser-produced positron beams has been made. The emittance values were derived through measurements of positron beam divergence and source size for different peak positron energies under various laser conditions. For one of these laser conditions, we used a one dimensional pepper-pot technique to refine the emittance value. The laser-produced positrons have a geometric emittance between 100 and 500 mm{center_dot}mrad, comparable to the positron sources used at existing accelerators. With 10{sup 10}-10{sup 12} positrons per bunch, this low emittance beam, which is quasi-monoenergetic in the energy range of 5-20 MeV, may be useful as an alternative positron source for future accelerators.

  3. Initial Operation of the Proto-MPEX High Intensity Plasma Source

    NASA Astrophysics Data System (ADS)

    Caughman, J. B. O.; Goulding, R. H.; Biewer, T. M.; Bigelow, T. S.; Diem, S. J.; Pesavento, P. V.; Rapp, J.; Ray, H. B.; Shaw, G. C.; Luo, G.-N.

    2014-10-01

    The Prototype Materials Plasma Experiment (Proto-MPEX) is a linear high-intensity rf plasma source that combines a high-density helicon plasma generator with electron and ion heating. It is being used to study the physics of heating over-dense plasmas, as well as exploring source interactions with a downstream target. The helicon plasma is produced by coupling 13.56 MHz rf power at levels up to 100 kW. Microwaves at 28 GHz (up to ~200 kW) are coupled to the electrons in the over-dense helicon plasma via Electron Bernstein Waves (EBW). Ion cyclotron heating (~30 kW) is via a magnetic beach approach. Tungsten baffles are used to help control neutral pressure between the helicon source and a tungsten target. Plasma diagnostics include Thomson Scattering and a retarding field energy analyzer to determine plasma parameters near the target, while a microwave interferometer and Langmuir probes are used to determine plasma parameters near the source and elsewhere in the system. High plasma densities have been produced in He (>3 1019/m3) and D (>1.5 1019/m3) , and operation in magnetic field strengths up to 1 T has been demonstrated. Details of the experimental results will be presented, as well as future plans for studying plasma surface interactions and rf antenna plasma interactions. ORNL is managed by UT-Battelle, LLC, for the U.S. DOE under Contract DE-AC-05-00OR22725.

  4. Initial results from the ISEE-1 and -2 plasma wave investigation

    Microsoft Academic Search

    D. A. Gurnett; R. R. Anderson; F. L. Scarf; R. W. Fredricks; E. J. Smith

    1979-01-01

    A survey of initial results from the plasma-wave investigation on the ISEE 1 and 2 spacecraft is presented. The plasma-wave instruments employed are designed to provide measurements of the electric and magnetic fields of plasma waves over the frequency range from about 5 Hz to 300 kHz. Several representative satellite passes are analyzed in detail and discussed. The results considered

  5. Treatment Carbon Dioxide Using Atmospheric Non-thermal Plasma Produced by Surface Discharge

    Microsoft Academic Search

    Nobuya Hayashi; Hiroshi Yoshida; Saburoh Satoh; Chobei Yamabe

    2004-01-01

    Decomposition and fixation of carbon dioxide (CO_2) were studied using a non-thermal plasma produced by the surface discharge. The mixture gas of carbon dioxide and hydrogen or water vapor was introduced to a discharge reactor in order to deoxidize carbon dioxide and produce organic compounds. The effective condition of the treatment was investigated by controlling several parameters such as a

  6. Optimizing laser produced plasmas for efficient extreme ultraviolet and soft X-ray light sources

    NASA Astrophysics Data System (ADS)

    Sizyuk, Tatyana; Hassanein, Ahmed

    2014-08-01

    Photon sources produced by laser beams with moderate laser intensities, up to 1014 W/cm2, are being developed for many industrial applications. The performance requirements for high volume manufacture devices necessitate extensive experimental research supported by theoretical plasma analysis and modeling predictions. We simulated laser produced plasma sources currently being developed for several applications such as extreme ultraviolet lithography using 13.5% 1% nm bandwidth, possibly beyond extreme ultraviolet lithography using 6. nm wavelengths, and water-window microscopy utilizing 2.48 nm (La-?) and 2.88 nm (He-?) emission. We comprehensively modeled plasma evolution from solid/liquid tin, gadolinium, and nitrogen targets as three promising materials for the above described sources, respectively. Results of our analysis for plasma characteristics during the entire course of plasma evolution showed the dependence of source conversion efficiency (CE), i.e., laser energy to photons at the desired wavelength, on plasma electron density gradient. Our results showed that utilizing laser intensities which produce hotter plasma than the optimum emission temperatures allows increasing CE for all considered sources that, however, restricted by the reabsorption processes around the main emission region and this restriction is especially actual for the 6. nm sources.

  7. Injection of a coaxial-gun-produced magnetized plasma into a background helicon plasma

    NASA Astrophysics Data System (ADS)

    Zhang, Yue; Lynn, Alan; Gilmore, Mark; Hsu, Scott

    2014-10-01

    A compact coaxial plasma gun is employed for experimental investigation of plasma bubble relaxation into a lower density background plasma. Experiments are being conducted in the linear device HelCat at UNM. The gun is powered by a 120-uF ignitron-switched capacitor bank, which is operated in a range of 5 to 10 kV and 100 kA. Multiple diagnostics are employed to investigate the plasma relaxation process. Magnetized argon plasma bubbles with velocities 1.2Cs, densities 1020 m-3 and electron temperature 13eV have been achieved. The background helicon plasma has density 1013 m-3, magnetic field from 200 to 500 Gauss and electron temperature 1eV. Several distinct operational regimes with qualitatively different dynamics are identified by fast CCD camera images. Additionally a B-dot probe array has been employed to measure the spatial toroidal and poloidal magnetic flux evolution to identify plasma bubble configurations. Experimental data and analysis will be presented.

  8. A New Floating-Probe for Measurement of Insulated Plasma Produced by Radio-Frequency Power

    NASA Astrophysics Data System (ADS)

    Taniuchi, Yasuyuki; Yamada, Toshinori; Tokieda, Takanori; Utsumi, Michiaki; Isomura, Masao; Shindo, Haruo

    2012-11-01

    The paper provides a new probe method which enables us to measure parameters of plasmas produced in insulated vessel. In particular, the measurements of electron temperature and density are all made in floating condition of probe, so that there is no need to draw net current from plasma. The method is based on measurement of the functional relationship between the floating potential and the heating voltage of emissive probe. In the first place, the measured parameters of plasma produced in the metal vessel are shown, demonstrating how a new probe works. In the second place, the measurement in the quartz discharge tube is shown, and the measured data by the present method are compared with those obtained by the conventional double probe, demonstrating that they are consistent. It is emphasized that the present new method is a first success in floating probe to be able to measure all plasma parameters.

  9. Non-equilibrium plasma produced by intense pulse lasers and relative diagnostics

    NASA Astrophysics Data System (ADS)

    Torrisi, L.

    2013-12-01

    Non-equilibrium plasmas generated by pulsed laser intensities between 1010 and 1016 W cm-2 can be produced in high vacuum conditions. Thick and thin irradiated targets show non-isotropic radiation emission of photons, electrons and ions. High energetic ions, emitted along the normal to the target surface, are driven by high electric fields developed in plasma charge separation. Plasmas are characterized in terms of equivalent temperature, density, particle energy distributions and angular distribution, ion charge state distributions and the ion acceleration driving field. Plasma diagnostic methods are based mainly on time-of-flight techniques using ion collectors, SiC semiconductor detectors and ion energy analysers. Thomson parabola spectrometry, track detection and mass spectrometry give further characterizations. Investigations demonstrated that plasma properties depend strongly on the laser's characteristics, target composition and irradiation conditions. Results relative to ion and proton acceleration appear very interesting for many applications in the field of nuclear physics, matter structure, microelectronics, biology and medicine.

  10. Plasma waves produced by the xenon ion beam experiment on the Porcupine sounding rocket

    NASA Technical Reports Server (NTRS)

    Kintner, P. M.; Kelley, M.

    1982-01-01

    The production of electrostatic ion cyclotron waves by a perpendicular ion beam in the F-region ionosphere is described. The ion beam experiment was part of the Porcupine program and produced electrostatic hydrogen cyclotron waves just above harmonics of the hydrogen cyclotron frequency. The plasma process may be thought of as a magnetized background ionosphere through which an unmagnetized beam is flowing. The dispersion equation for this hypothesis is constructed and solved. Preliminary solutions agree well with the observed plasma waves.

  11. Excitation of the modified Simon-Hoh instability in an electron beam produced plasma

    Microsoft Academic Search

    Y. Sakawa; C. Joshi; P. K. Kaw; F. F. Chen; V. K. Jain

    1993-01-01

    An intermediate frequency (fci?f?fce) electrostatic instability has been observed in an electron beam produced, cylindrical plasma column. This instability has been identified as a new instability, the modified SimonHoh instability (MSHI), which has an instability mechanism similar to the SimonHoh instability (SHI). This instability can occur in a cylindrical collisionless plasma if a radial dc electric field exists and if

  12. Precision closed bomb calorimeter for testing flame and gas producing initiators

    NASA Technical Reports Server (NTRS)

    Carpenter, D. R., Jr.; Taylor, A. C., Jr.

    1972-01-01

    A calorimeter has been developed under this study to help meet the needs of accurate performance monitoring of electrically or mechanically actuated flame and gas producing devices, such as squib-type initiators. A ten cubic centimeter closed bomb (closed volume) calorimeter was designed to provide a standard pressure trace and to measure a nominal 50 calorie output, using the basic components of a Parr Model 1411 calorimeter. Two prototype bombs were fabricated, pressure tested to 2600 psi, and extensively evaluated.

  13. Overdense Plasmas Produced by Electron Cyclotron Heating in a Linear Multipole

    NASA Astrophysics Data System (ADS)

    Fukao, Masayuki; Matsuura, Ken-ichi

    1994-07-01

    A report is given of characteristics of a plasma produced by electron cyclotron heating (ECH) in a linear multipole (LMP) field configuration. The electron density measured by a 6 mm microwave interferometer reached 21012 cm-3, which corresponds to 30 times the cutoff density for the 2.45 GHz RF source. On the basis of the spatial distributions of electron density, electron temperature and space potential measured with Langmuir and emissive probes, the mechanism of overdense plasma production is discussed. Consideration is also given to steady operation of this configuration, which is essential for practical plasma process applications.

  14. On the atomic state densities of plasmas produced by the ``torche injection axiale''

    NASA Astrophysics Data System (ADS)

    Jonkers, J.; Vos, H. P. C.; van der Mullen, J. A. M.; Timmermans, E. A. H.

    1996-04-01

    The atomic state densities of helium and argon plasmas produced by the microwave driven plasma torch called the "torche injection axiale" are presented. They are obtained by absolute line intensity measurements of the excited states and by applying the ideal gas law to the ground state. It will be shown that the atomic state distribution function (ASDF) does not obey the Saha-Boltzmann law: the ASDF cannot be described by one temperature. From the shape of the ASDF it can be concluded that the plasma is ionising. By extrapolating the measured state densities towards the ionisation limit, a minimum value of the electron density can be determined.

  15. A study of subsurface crack initiation produced by rolling contact fatigue

    NASA Technical Reports Server (NTRS)

    Kumar, Arun M.; Hahn, George T.; Rubin, Carol A.

    1993-01-01

    Results of subsurface crack initiation studies produced by pure rolling contact fatigue in 7075-T6 aluminum alloy are presented in this article. Microstructural changes and subsequent crack initiation below the contacting surface in cylindrical test specimens subjected to repeated rolling contact are illustrated. The rolling conditions are simulated in a three-dimensional elastic-plastic finite element model in order to estimate the plastic strains and residual stresses in the test material. The numerically estimated distribution of plastic strains in the model correlate well with the extent of microstructural changes observed in the test specimen. Results also indicate that a combination of plastic strains and low values of residual stresses is conducive to subsurface crack initiation and growth.

  16. Apparatus and method to enhance X-ray production in laser produced plasmas

    DOEpatents

    Augustoni, Arnold L. (Albuquerque, NM); Gerardo, James B. (Albuquerque, NM); Raymond, Thomas D. (Albuquerque, NM)

    1992-01-01

    Method and apparatus for generating x-rays for use in, for instance, x-ray photolithography. The method of generating x-rays includes the steps of providing a target and irradiating the target with a laser system which produces a train of sub-pulses to generate an x-ray producing plasma. The sub-pulses are of both high intensity and short duration. The apparatus for generating x-rays from a plasma includes a vacuum chamber, a target supported within the chamber and a laser system, including a short storage time laser.

  17. A comparison of the emissions, densities, temperatures, and debris features of laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Coons, Ryan William

    Tin and lithium plasmas emit efficiently in the in-band region (13.5 nm with 2% bandwidth) necessary for extreme ultraviolet (EUV) lithography. A detailed comparison of the atomic and ionic debris, as well as the emission features of tin and lithium plasmas has been conducted under identical experimental conditions. Planar slabs of pure tin and lithium were irradiated with 1064 nm, 9 ns neodymium-doped yttrium aluminum garnet (Nd:YAG) laser pulses for producing plasmas. A suite of diagnostics were used to analyze the emission and debris features, including optical emission spectroscopy (OES), a Faraday cup, an EUV pinhole camera, a power tool for the absolute measurement of EUV conversion efficiency (CE), etc. The results show that tin plasmas provide a CE nearly twice that of lithium. However, the kinetic energies of tin ions are considerably higher, though with a lower flux. OES studies have shown that the kinetic energies of neutral species are substantially lower compared to that of the charged particle species. Laser-produced lithium plasmas were also studied in closer detail with 2D OES, conventional 1D OES to determine the electron density throughout the entire plasma from the Stark broadening of the spectral line emissions, along with Nomarski interferometry. The electron temperatures of both neutral and singly-ionized species were estimated through a comparison of the line intensities by using the Boltzmann plot method. These results were then compared to previous studies of tin plasmas under similar conditions. Lithium plasma density was also evaluated using 2D OES in air, argon, and helium buffer gas environments of different pressures. These studies were then repeated along several planes perpendicular to the target surface, to evaluate any radial dependence on lithium plasma electron density.

  18. Shock formation in supersonic cluster jets and its effect on axially modulated laser-produced plasma waveguides.

    PubMed

    Yoon, S J; Goers, A J; Hine, G A; Magill, J D; Elle, J A; Chen, Y-H; Milchberg, H M

    2013-07-01

    We examine the generation of axially modulated plasmas produced from cluster jets whose supersonic flow is intersected by thin wires. Such plasmas have application to modulated plasma waveguides. By appropriately limiting shock waves from the wires, plasma axial modulation periods can be as small as 70 ?m, with plasma structures as narrow as 45 m. The effect of shocks is eliminated with increased cluster size accompanied by a reduced monomer component of the flow. PMID:23842374

  19. Experimental investigation of different structures of a radio frequency produced plasma column

    NASA Astrophysics Data System (ADS)

    Kumar, Rajneesh; Bora, Dhiraj

    2010-04-01

    Experimental results on the observation of spatial structures appearing in a radio frequency (rf) produced plasma column are presented in this paper. A plasma column of length 30 cm is formed in a glass tube by applying rf power from a cw generator. It is observed that by changing the operating parameters, e.g., input power, working pressure, drive frequency, diameter of glass tube, background gases, etc., single plasma column transforms into stationary/moving striations and helical and spiral structures. For a better understanding of these observations, experiments are also carried out to study the electric field profile of these structures in the plasma. Findings of this study reveal that surface wave produced plasma column transversally bifurcates and transforms into stationary striations. With further increase in working pressure, stationary striations become moving striations with linear and rotational motions and finally rotating plasma column bifurcates longitudinally and a helical structure is formed, which can also be transformed into a spiral structure. Electric field profile of each structure is entirely different from that of the other structure.

  20. [Preliminary study of atomic emission spectrometry of Ti (H) plasma produced by vacuum arc ion source].

    PubMed

    Deng, Chun-Feng; Wu, Chun-Lei; Wang, Yi-Fu; Lu, Biao; Wen, Zhong-Wei

    2014-03-01

    In order to study the discharge process of vacuum arc ion source, make a detail description of the discharge plasma, and lay the foundation for further research on ion source, atomic emission spectrometry was used to diagnose the parameters of plasma produced by vaccum arc ion source. In the present paper, two kinds of analysis method for the emission spectra data collected by a spectrometer were developed. Those were based in the stark broadening of spectral lines and Saba-Boltzmann equation. Using those two methods, the electron temperature, electron number density and the ion temperature of the plasma can be determined. The emission spectroscopy data used in this paper was collected from the plasma produced by a vacuum are ion source whose cathode was made by Ti material (which adsorbed hydrogen during storage procedure). Both of the two methods were used to diagnose the plasma parameters and judge the thermal motion state of the plasma. Otherwise, the validity of the diagnostic results by the two methods were analyzed and compared. In addition, the affection from laboratory background radiation during the spectral acquisition process was discussed. PMID:25208416

  1. Dynamics of neutrals and ions in an ultrafast laser produced Zn plasma

    NASA Astrophysics Data System (ADS)

    Smijesh, N.; Rao, Kavya H.; Philip, Reji

    2015-03-01

    Optical time of flight dynamics of neutrals and ions in an ultrafast laser produced zinc plasma generated by irradiating a solid zinc target using 100 fs laser pulses is investigated. An acceleration of ions is observed which arises from internal Coulomb forces acting between charged species in the plasma. Some of the fast ions recombine with electrons in the plasma and generate fast neutrals. Plasma plume imaging performed at various ambient pressures indicates adiabatic expansion at lower pressures and plume front deceleration at higher pressures: at lower pressures the plume front-time (R-t) plot displays a linear expansion, shock wave model fits to the data at 5 Torr and at higher pressures the data fits better to the drag model. Furthermore, around an intermediate pressure of 10 Torr, the R-t plot fits to the shock wave model at earlier stages of plasma expansion, while it fits to the drag model at the later stages. These investigations provide relevant information on the acceleration of ions and neutrals in an expanding zinc plasma plume produced by ultrafast laser pulses.

  2. Experimental study of XUV laser produced plasma sheet for microwave agile mirror application

    SciTech Connect

    Shen, W.; Scharer, J.E.; Porter, B.G.; Lam, N.T.; Kelly, K.L. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Electrical and Computer Engineering

    1995-12-31

    An excimer-laser ({lambda} = 193 nm, {tau} = 17 nS, E = 20 mJ) along with a cylindrical lens system is utilized to produce a sheet plasma in an organic gas (TMAE). The plasma has a peak density of 3.5 {times} 10{sup 13} cm{sup {minus}3} and a ``sheet`` like profile of 0.2--0.7 cm x 8 cm x 20 cm. The effect of the lens system on the plasma sheet thickness is examined. The triple probe measured plasma temperature agrees with the postulation of single-photon absorption-ionization process. The plasma density spatial decay along the laser beam, which is associated with TMAE photon absorption length, is measured. The absorption length is found to be a function of base pressure of the neutral working gas. The authors have obtained an optimal window of TMAE base pressure at 50--150 mTorr. Within this optimal pressure range a plasma formation can have a long absorption length, relatively high plasma density, and lifetime of 5 {micro}s. A 1-D plasma diffusion model is proposed and solved both analytically and numerically. Comparison of the modeling and the measured results yields accurate values for the plasma diffusion and recombination coefficients. The electron-ion recombination coefficient is determined to be 2.4 {times} 10{sup {minus}6} cm{sup 3} s{sup {minus}1}. This is within 30% of that previously reported measurement without a lens system. The study indicates that plasma dynamics is dominated by the recombination process except for a very short period after the laser pulse is turned off.

  3. X-ray Laser Satellites from Subpicosecond Laser-Produced Plasma

    Microsoft Academic Search

    A. Maksimchuk; M. Nantel; G. Ma; D. Umstadter; S. A. Pikuz; I. Yu. Skobelev; A. Ya. Faenov

    1998-01-01

    We measure experimentally previously unobserved x-ray lines that are produced during the interaction high-intensity subpicosecond laser pulses (400 fs, 2J, 10^18 W\\/cm^2) with solid targets. These satellites are the result of the nonlinear interaction of the intense laser field with the plasma, which produces new spectral line in keV region around parity-forbidden transitions B^* arrow B of the multiply charged

  4. Single-walled carbon nanotubes produced by plasma-enhanced chemical vapor deposition

    Microsoft Academic Search

    Toshiaki Kato; Goo-Hwan Jeong; Takamichi Hirata; Rikizo Hatakeyama; Kazuyuki Tohji; Kenichi Motomiya

    2003-01-01

    Single-walled carbon nanotubes (SWNTs) are produced for the first time using plasma-enhanced chemical vapor deposition method. In this method, not only SWNTs in the form of thin bundles but also individually grown SWNTs are produced at a quite low-synthesis temperature (550 C). According to analyses by field emission gun transmission electron microscopy and Raman scattering spectroscopy, it is conjectured that

  5. Two-dimensional evaluation of an ion plasma produced by pulsed lasers extracted by non-parallel collectors

    NASA Astrophysics Data System (ADS)

    Mahdieh, M. H.; Gavili, A.

    2003-11-01

    Two-dimensional hydrodynamics of ion extraction from quasi-neutral plasmas has been calculated numerically for non-parallel ion extractors, and the results compared with those for the parallel case. The ions were assumed to be initially uniform with a very steep density profile at the boundaries, and held between two non-parallel metal plates as cathode and anode with fixed potentials. Experimentally, tunable pulsed lasers through stepwise photo-excitation and photo-ionization or multi-photo-ionization processes can produce such plasma. Poisson's equation was solved simultaneously with the equations of mass and momentum, assuming the Maxwell-Boltzmann distribution for electrons. Ordinary Cartesian co-ordinates are not suitable for the rotated extractor geometry; therefore using the `algebraic method' a transformation from the physical domain into the computational rectangular plane is applied for analysing the irregular boundaries. Such a technique provides adequate resolution for the boundary layer. Using a first-order explicit upwind differencing in an appropriate transformed Cartesian co-ordinate system, the hydrodynamics of the plasma ions between the two non-parallel electrodes was evaluated. In these calculations electric potential, ion density between the two electrodes, and the extraction time were assessed, considering three separate regions for the plasma, i.e. the ion sheath where (ni?neapprox0), the transition region (pre-sheath) (ni = ne), and the quasi-neutral plasma (ni-ne?ni). The results were compared with those for parallel electrodes. A significant discrepancy was found between the two results. From the calculation, the non-uniform asymmetric potential contour, and the ion density contour across the plasma, were obtained for the non-parallel electrodes. For comparison with the parallel extractors, we have also obtained almost the same extraction time for the non-parallel extractors.

  6. Characterization of laser-produced plasma density profiles using grid image refractometry

    SciTech Connect

    Craxton, R.S.; Turner, F.S.; Hoefen, R. (Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States)); Darrow, C. (Lawrence Livermore National Laboratory, P.O. Box 5508, Livermore, California 94550 (United States)); Gabl, E.F.; Busch, G.E. (KMS Fusion Inc., 700 KMS Place, Ann Arbor, Michigan 48106 (United States))

    1993-12-01

    Grid image refractometry (GIR) is proposed as a technique for determining the two-dimensional density profiles of long scale-length laser-produced plasmas. Its distinctive feature is that an optical probe beam is broken up into rays'' by being passed through a grid before traversing the plasma. The refraction angles of the rays are measured by imaging the plasma at two or more object planes and are integrated to yield the phase front. For cylindrically symmetric plasmas the density profile is then determined using Abel inversion. The feasibility of GIR is illustrated by an experiment in which a thick CH target was irradiated with [similar to]100 J of 527 nm radiation and diagnosed with a 20 ps, 263 nm probe. The resulting density profile is substantially larger than any that have previously been reported using interferometry and compares quite closely with hydrodynamic simulations.

  7. Techniques for soft x-ray absorption in laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Burkhalter, P. G.; Mehlman, G.; Newman, D. A.; Ripin, B. H.

    1990-10-01

    Interest in x-ray absorption derives from soft x-ray transport studies to characterize laser-solid-interaction effects. The object of this work was to determine whether x-ray absorption features were measurable in laser-produced plasmas from solid targets. X-ray emission was made using high-atomic-number microsphere targets irradiated with a focused beam of the Pharos laser while the laser-solid-interaction plasmas were generated by a second beam in Al foil targets. High-resolution, spatially resolved x-ray spectra were collected with instrumentation and geometry similar to previous tracer-dot spectroscopy measurements of plasma profile parameters. Soft x-ray absorption lines, observed at different distances from the aluminum target surface, may be related to density gradients in the laser-generated plasmas.

  8. First experiments probing the collision of parallel magnetic fields using laser-produced plasmas

    DOE PAGESBeta

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

    2015-04-01

    Novel experiments to study the strongly-driven collision of parallel magnetic fields in ?~10, laser-produced plasmas have been conducted using monoenergetic proton radiography. These experiments were designed to probe the process of magnetic flux pileup, which has been identified in prior laser-plasma experiments as a key physical mechanism in the reconnection of anti-parallel magnetic fields when the reconnection inflow is dominated by strong plasma flows. In the present experiments using colliding plasmas carrying parallel magnetic fields, the magnetic flux is found to be conserved and slightly compressed in the collision region. Two-dimensional (2D) particle-in-cell (PIC) simulations predict a stronger flux compressionmoreand amplification of the magnetic field strength, and this discrepancy is attributed to the three-dimensional (3D) collision geometry. Future experiments may drive a stronger collision and further explore flux pileup in the context of the strongly-driven interaction of magnetic fields.less

  9. First experiments probing the collision of parallel magnetic fields using laser-produced plasmas

    DOE PAGESBeta

    Rosenberg, M. J. [Plasma Science and Fusion Center and Massachusetts Institute of Technology, Cambridge, MA (United States); Li, C. K. [Plasma Science and Fusion Center and Massachusetts Institute of Technology, Cambridge, MA (United States); Fox, W. [Princeton Plasma Physics Laboratory, Princeton, NJ (United States)] (ORCID:000000016289858X); Igumenshchev, I. [University of Rochester, NY (United States). Laboratory for Laser Energetics; Seguin, F. H. [Plasma Science and Fusion Center and Massachusetts Institute of Technology, Cambridge, MA (United States); Town, R. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Frenje, J. A. [Plasma Science and Fusion Center and Massachusetts Institute of Technology, Cambridge, MA (United States)] (ORCID:0000000168460378); Stoeckl, C. [University of Rochester, NY (United States). Laboratory for Laser Energetics; Glebov, V. [University of Rochester, NY (United States). Laboratory for Laser Energetics; Petrasso, R. D. [Plasma Science and Fusion Center and Massachusetts Institute of Technology, Cambridge, MA (United States)] (ORCID:0000000258834054)

    2015-04-01

    Novel experiments to study the strongly-driven collision of parallel magnetic fields in ?~10, laser-produced plasmas have been conducted using monoenergetic proton radiography. These experiments were designed to probe the process of magnetic flux pileup, which has been identified in prior laser-plasma experiments as a key physical mechanism in the reconnection of anti-parallel magnetic fields when the reconnection inflow is dominated by strong plasma flows. In the present experiments using colliding plasmas carrying parallel magnetic fields, the magnetic flux is found to be conserved and slightly compressed in the collision region. Two-dimensional (2D) particle-in-cell (PIC) simulations predict a stronger flux compression and amplification of the magnetic field strength, and this discrepancy is attributed to the three-dimensional (3D) collision geometry. Future experiments may drive a stronger collision and further explore flux pileup in the context of the strongly-driven interaction of magnetic fields.

  10. Angular distribution of ions and extreme ultraviolet emission in laser-produced tin droplet plasma

    NASA Astrophysics Data System (ADS)

    Chen, Hong; Wang, Xinbing; Duan, Lian; Lan, Hui; Chen, Ziqi; Zuo, Duluo; Lu, Peixiang

    2015-05-01

    Angular-resolved ion time-of-flight spectra as well as extreme ultraviolet radiation in laser-produced tin droplet plasma are investigated experimentally and theoretically. Tin droplets with a diameter of 150 ?m are irradiated by a pulsed Nd:YAG laser. The ion time-of-flight spectra measured from the plasma formed by laser irradiation of the tin droplets are interpreted in terms of a theoretical elliptical Druyvesteyn distribution to deduce ion density distributions including kinetic temperatures of the plasma. The opacity of the plasma for extreme ultraviolet radiation is calculated based on the deduced ion densities and temperatures, and the angular distribution of extreme ultraviolet radiation is expressed as a function of the opacity using the Beer-Lambert law. Our results show that the calculated angular distribution of extreme ultraviolet radiation is in satisfactory agreement with the experimental data.

  11. Analysis of atomic and ion debris features of laser-produced Sn and Li plasmas

    SciTech Connect

    Coons, R. W.; Harilal, S. S.; Campos, D.; Hassanein, A. [School of Nuclear Engineering and Center for Materials Under Extreme Environment, Purdue University, West Lafayette, Indiana 47907 (United States)

    2010-09-15

    Tin and lithium plasmas emit efficiently in the in-band region (13.5 nm with 2% bandwidth) necessary for extreme ultraviolet (EUV) lithography. We have made a detailed comparison of the atomic and ionic debris, as well as the emission features of Sn and Li plasmas under identical experimental conditions. Planar slabs of pure Sn and Li were irradiated with 1064 nm, 9 ns neodymium-doped yttrium aluminum garnet laser pulses for producing plasmas. A suite of diagnostics were used to analyze the emission and debris features, including optical emission spectroscopy (OES), a Faraday cup, an EUV pinhole camera, the absolute measurement of EUV conversion efficiency (CE), etc. Our results show that Sn plasmas provide a CE nearly twice that of Li. However, the kinetic energies of Sn ions are considerably higher, though with a lower flux. OES studies have showed that the kinetic energies of neutral species are substantially lower compared to that of the charged particle species.

  12. Application of escape probability to line transfer in laser-produced plasmas

    SciTech Connect

    Lee, Y.T.; London, R.A.; Zimmerman, G.B. (Lawrence Livermore National Laboratory, Livermore, CA (USA)); Hagelstein, P.L. (Massachusetts Institute of Technology, Cambridge, MA (USA))

    1990-11-01

    The application of an escape probability method to treat transfer of optically thick lines in laser-produced plasmas in plane-parallel geometry is described. The escape probability calculated is valid in a plasma with any locally linear velocity profile. It reduces to the standard result for a static plasma and to the result of Sobolev (Sov. Astron. Astrophys. J. {bold 1}, 678 (1957)) for large ion velocity gradients. As examples, escape probability is applied to model the effect of optically thick line trapping in both exploding foil and ablating massive slab targets. Compared to detailed numerical calculations for the line transfer in these targets, the escape probability gives quite accurate estimates. This can be understood in terms of the large Doppler shifts in the line profiles that are generated by the ion velocity in the plasmas.

  13. Properties of a capillary discharge-produced argon plasma waveguide for shorter wavelength source application

    SciTech Connect

    Sakai, Shohei; Miyazawa, Jun [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Higashiguchi, Takeshi; Yugami, Noboru [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Bobrova, Nadezhda; Sasorov, Pavel [Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya str. 25, 117218 Moscow (Russian Federation); Sentoku, Yasuhiko [Department of Physics, University of Nevada, Mail Stop 220, Reno, Nevada 89506 (United States); Kodama, Ryosuke [Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Graduate School of Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2011-10-15

    We report the operation of a discharge-produced argon (Ar) plasma waveguide in an alumina (Al{sub 2}O{sub 3}) capillary to guide a 10{sup 16}-W/cm{sup 2} ultrashort laser pulse for shorter wavelength light sources at high repetition rate operation. The electron density in the plasma channel was measured to be 1 x 10{sup 18} cm{sup -3}. Modeling with a one-dimensional magnetrohydrodynamic code was used to evaluate the degree of ionization of Ar in the preformed plasma channel. The observed spectrum of the laser pulse after propagation in the argon plasma waveguide was not modified and was well reproduced by a particle in cell simulation.

  14. Ion shock acceleration by large amplitude slow ion acoustic double layers in laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Eliasson, B.

    2014-02-01

    A kinetic model for the shock acceleration of ions in laser-produced plasmas is developed. A fraction of the warm ions are accelerated by the large amplitude monotonic potential of the shock created due the plasma compression and electron heating by the laser. The kinetic model for the monotonic shock is based on the slow ion acoustic double layer (SIADL). It is found that the amplitude of the large amplitude SIADL is almost uniquely defined by the electron temperature. Therefore, a balance between electron heating and plasma compression is needed for optimal ion acceleration by this scheme. Typical Mach numbers of the monotonic shocks are close to 1.5. The scheme could potentially produce monoenergetic ions with a relative energy spread of less than 1%. The model is compared with recent simulations and experiments, where efficient shocks acceleration and production of monoenergetic protons have been observed. Similarities and differences with other shock models are pointed out and discussed.

  15. Ion shock acceleration by large amplitude slow ion acoustic double layers in laser-produced plasmas

    SciTech Connect

    Eliasson, B. [SUPA, Physics Department, University of Strathclyde, John Anderson Building, Glasgow G4 0NG (United Kingdom)] [SUPA, Physics Department, University of Strathclyde, John Anderson Building, Glasgow G4 0NG (United Kingdom)

    2014-02-15

    A kinetic model for the shock acceleration of ions in laser-produced plasmas is developed. A fraction of the warm ions are accelerated by the large amplitude monotonic potential of the shock created due the plasma compression and electron heating by the laser. The kinetic model for the monotonic shock is based on the slow ion acoustic double layer (SIADL). It is found that the amplitude of the large amplitude SIADL is almost uniquely defined by the electron temperature. Therefore, a balance between electron heating and plasma compression is needed for optimal ion acceleration by this scheme. Typical Mach numbers of the monotonic shocks are close to 1.5. The scheme could potentially produce monoenergetic ions with a relative energy spread of less than 1%. The model is compared with recent simulations and experiments, where efficient shocks acceleration and production of monoenergetic protons have been observed. Similarities and differences with other shock models are pointed out and discussed.

  16. Experimental studies of stimulated Raman scattering in reactor-size, laser-produced plasmas

    SciTech Connect

    Darrow, C.B.; Drake, R.P.; Montgomery, D.S.; Young, P.E.; Estabrook, K.; Kruer, W.L. (Lawrence Livermore National Laboratory, Livermore, California 94550 (USA)); Johnston, T.W. (Institut National de la Recherche Scientifique-Energie, Varennes, Quebec JOL 2PO, Canada (CA))

    1991-06-01

    In this paper the results of experiments designed to provide information regarding the scaling of the stimulated Raman scattering (SRS) instability in long-scale-length, inertial- confinement-fusion-reactor-size plasmas are described. Reactor-scale plasma conditions were experimentally simulated by exploding thin CH foils with nine beams of the Nova laser (Rev. Sci. Instrum. {bold 57}, 2101 (1986)). Using a one-dimensional hydro model, the target and irradiation parameters were chosen to produce the largest-possible scale length plasma consistent with the energy and pulse width capabilities of Nova. The SRS emissions, driven by both the nine plasma-production beams and a tightly focused and delayed tenth beam, were recorded using an angularly resolved photodiode array and a temporally resolved optical spectrometer. These measurements verified the production of a reactor-size plasma ({ital L}/{lambda} {approx} 5000) and indicated that the absolute levels of SRS backscatter detected in the present experiments have not increased relative to those measured in previous experiments despite a calculated sevenfold increase in the plasma density-gradient scale length. Inverse bremsstrahlung absorption of the scattered light is believed to be the dominant mechanism for this {ital apparent} saturation and, in this parameter regime, may enhance the effective thermal coupling between the incident laser and plasma densities below 0.15{ital n}{sub crit} where absorption of the incident laser light is typically weak.

  17. Reflectivity profiles of phase conjugate waves produced via four-wave mixing in laser plasmas

    SciTech Connect

    Gupta, G.P.; Sinha, B.K. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India)] [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India)

    1996-10-01

    Theoretical profiles of power reflectivity of a phase conjugate electromagnetic wave generated by nearly degenerate four-wave mixing in a carbon plasma via parametric decay instability (PDI) are studied. The plasma is considered to be produced by irradiating a carbon slab target with an Nd:glass high-power laser pulse at an intensity above the PDI threshold. The plasma refractive index corresponding to the PDI region is taken into account in the wave equations. Two electromagnetic pump waves counterpropagating in the plasma are Nd:glass laser light waves and a weak electromagnetic probe wave incident upon the plasma, which is very slightly frequency upshifted relative to the pump waves. The effects of the frequency and angular detuning between the pump and probe waves, pump wave intensity, and plasma parameters on the reflectivity profiles have been investigated. It is noted that the plasma refractive index significantly affects the reflectivity profiles of the phase conjugate wave. {copyright} {ital 1996 American Institute of Physics.}

  18. Experiments on radiation-driven waves produced during the production of a radially confined plasma column

    Microsoft Academic Search

    D. Dufresne; P. A. Pincosy; J.-P. Caressa; P. Bournot; M. Autric

    1978-01-01

    A plasma column radially confined by a magnetic field was produced in hydrogen by the light energy of a CO2 laser (200 J and a pulse length of 2 microsec). The absorption zone which normally propagates toward the laser from the focal spot was eliminated to permit the study, in an approximately constant column diameter, of front propagation regimes as

  19. Possibility of deexcitation of isomeric nuclei in plasmas produced by subpicosecond laser pulses

    SciTech Connect

    Afonin, V. I. [Russian Federal Nuclear Center, Zababakhin All-Russia Research Institute of Technical Physics (Russian Federation)

    2009-02-15

    Possible schemes of X-ray-activated deexcitation of isomers of rhodium, silver, tellurium, and bismuth are considered. It is shown that conditions necessary for deexcitation of rhodium isomer can, in principle, be achieved in a high-temperature solid-body-density plasma produced by an ultrashort laser pulse.

  20. Gas dynamic effects on formation of carbon dimers in laser-produced plasmas

    E-print Network

    Harilal, S. S.

    Gas dynamic effects on formation of carbon dimers in laser-produced plasmas K. F. Al-Shboul, S. S. Harilal,a) and A. Hassanein School of Nuclear Engineering and Center for Materials Under Extreme and nitrogen pressures on the dynamics of molecular species formation during laser ablation of carbon

  1. Indentation hardness of rough surfaces produced by plasma-based ion implantation processes

    Microsoft Academic Search

    Gelson Biscaia de Souza; Alexandre Mikowski; Carlos Maurcio Lepienski; Carlos Eugnio Foerster

    2010-01-01

    The thickness of layers produced by plasma based ion implantation (PBII) range from nano to micrometers. Consequently, mechanical properties of such layers demand the use of instrumented indentation (II). However, PBII processes promote roughness, which has strong influence on the reliability of hardness and elastic modulus measurements. In the present study, hardness was obtained by two different methods using II

  2. Currents and shear Alfven wave radiation generated by an exploding laser-produced plasma: Perpendicular incidence

    E-print Network

    California at Los Angles, University of

    Currents and shear Alfven wave radiation generated by an exploding laser-produced plasma be limited by large ambipolar fields. This charge separation results in the creation of current structures. This paper is an investigation of the reproducible current structures and shear Alfven wave radiation

  3. Influence of laser satellite transitions on spectroscopy of high-intensity laser-produced plasmas

    Microsoft Academic Search

    A. L. Osterheld; B. K. F. Young; J. Dunn; R. E. Stewart; I. Yu. Skobelev; A. Ya. Faenov; A. I. Magunov

    1997-01-01

    The oscillating electromagnetic field of an intense laser pulse can significantly affect the emission properties of ions in a plasma. For sufficiently intense laser fields, induced second order processes produce discrete radiative transitions. In addition, these induced radiative processes alter the level population kinetics, and the spectrum of spontaneous transitions. We discuss the effects of these processes on the n

  4. Spatial and spectral characterization of a laser produced plasma source for extreme ultraviolet metrology

    Microsoft Academic Search

    H. Legall; H. Stiel; U. Vogt; H. Schoennagel; P.-V. Nickles; J. Tuemmler; F. Scholz; F. Scholze

    2004-01-01

    We present a laser produced plasma (LPP) source optimized for metrology and the results of its radiometric characterization. The presented (LPP) source can be used for reflectometry and spectroscopy in the soft x-ray range. For these applications, stable operation with high spectral photon yields high reliability in continuous operation and, to reach high spectral resolution, a small source size and

  5. Intense electron emission due to picosecond laser-produced plasmas in high gradient electric fields

    Microsoft Academic Search

    X. J. Wang; T. Tsang; H. Kirk; T. Srinivasan-Rao; J. Fischer; K. Batchelor; P. Russell; R. C. Fernow

    1992-01-01

    Picosecond laser pulses at a wavelength of 266 nm have been focused onto a solid metal cathode in coincidence with high-gradient electric fields to produce high brightness electron beams. At power densities exceeding 10 exp 9 W\\/sq cm, a solid density plasma is formed and intense bursts of electrons are emitted from the target accompanied by macroscopic surface damage. An

  6. Picosecond 14.7 nm interferometry of high intensity laser-produced plasmas

    E-print Network

    Rocca, Jorge J.

    Picosecond 14.7 nm interferometry of high intensity laser-produced plasmas JAMES DUNN,1 JORGE 28 October 2004! Abstract We have developed a compact, 14.7 nm, sub-5 ps X-ray laser source development of the technique includ- ing utilizing a shorter wavelength, 4v harmonic at 266 nm wavelength

  7. Space and time-resolved soft x-ray emission from laser-produced magnesium plasma

    Microsoft Academic Search

    S. S. Harilal; C. V. Bindhu; H.-J. Kunze

    2001-01-01

    Soft x-ray emission from plasmas produced by ablation from a magnesium target employing a ruby laser is studied using a grazing incidence spectrograph in the spectral region 3-12 nm. Emission intensities are investigated for different ionic lines as a function of position, time after the maximum of the laser pulse and laser irradiance. A gated pinhole camera is employed for

  8. Ion acoustic instability driven by a temperature gradient in laser-produced plasmas

    Microsoft Academic Search

    A. V. Brantov; V. Yu. Bychenkov; W. Rozmus

    2001-01-01

    The return current instability excited in laser-produced plasmas by a temperature gradient has been studied using a nonlocal theory of electron transport. The transport model is applicable for an arbitrary ratio of the temperature inhomogeneity scale length to the collisional mean free path. It is demonstrated that nonlocal thermal effects have a significant impact on the ion acoustic instability growth

  9. Temporal evolution of the electric field intensity in pulsed surface-wave-produced plasmas

    Microsoft Academic Search

    A. Gamero; A. Sola; J. Cotrino; V. Colomer

    1989-01-01

    The authors present a study about the temporal evolution of the electric field intensity during the plasma formation process. The experimental measurements have been performed in argon gas at low pressure and using pulsed microwave power at 2.45 GHz to produce the discharge. From the electric field radial distribution of the surface wave and with experimental measurements of the electron

  10. Electron density and temperature measurements in a laser produced carbon plasma

    E-print Network

    Harilal, S. S.

    electron temperature and density at several sections located in front of the target surface. LineElectron density and temperature measurements in a laser produced carbon plasma S. S. Harilal, C. V intensities of successive ionization states of carbon were used for electron temperature calculations. Stark

  11. Laser-Produced Plasma Diagnostics by a Combination of Schlieren Method and Mach-Zehnder Interferometry

    NASA Astrophysics Data System (ADS)

    Iwase, O.; S, W.; Hoffmann, D. H. H.; Roth, M.; Stckl, C.; Geissel, M.; Seelig, W.; Bock, R.

    1998-12-01

    An optical method for laser-produced plasma diagnostics, for which a crucial study is a shock-wave phenomena, is newly suggested as a combination of the well-known Schlieren method to study shock-wave phenomena and Mach-Zehnder interferometry for evaluating the electron density.

  12. Synthesis of oxide nanoparticles via microwave plasma decomposition of initial materials

    Microsoft Academic Search

    Jong Hun Kim; Yong Cheol Hong; Han Sup Uhm

    2007-01-01

    Vanadium pentoxide (V2O5) and zinc oxide (ZnO) powders were synthesized by making use of an atmospheric microwave plasma torch. Zn granules for ZnO and vanadium oxytrichloride (VOCl3) in liquid for V2O5 were used as initial materials. A sample for V2O5 consisted of nano- and micro-structured particles aligned with the plasma reactor structure. A sample for ZnO was typical nanorods with

  13. Plasma reforming and partial oxidation of hydrocarbon fuel vapor to produce synthesis gas and/or hydrogen gas

    DOEpatents

    Kong, Peter C.; Detering, Brent A.

    2003-08-19

    Methods and systems for treating vapors from fuels such as gasoline or diesel fuel in an internal combustion engine, to form hydrogen gas or synthesis gas, which can then be burned in the engine to produce more power. Fuel vapor, or a mixture of fuel vapor and exhaust gas and/or air, is contacted with a plasma, to promote reforming reactions between the fuel vapor and exhaust gas to produce carbon monoxide and hydrogen gas, partial oxidation reactions between the fuel vapor and air to produce carbon monoxide and hydrogen gas, or direct hydrogen and carbon particle production from the fuel vapor. The plasma can be a thermal plasma or a non-thermal plasma. The plasma can be produced in a plasma generating device which can be preheated by contact with at least a portion of the hot exhaust gas stream, thereby decreasing the power requirements of the plasma generating device.

  14. Plasma Reforming And Partial Oxidation Of Hydrocarbon Fuel Vapor To Produce Synthesis Gas And/Or Hydrogen Gas

    DOEpatents

    Kong, Peter C. (Idaho Falls, ID); Detering, Brent A. (Idaho Falls, ID)

    2004-10-19

    Methods and systems are disclosed for treating vapors from fuels such as gasoline or diesel fuel in an internal combustion engine, to form hydrogen gas or synthesis gas, which can then be burned in the engine to produce more power. Fuel vapor, or a mixture of fuel vapor and exhaust gas and/or air, is contacted with a plasma, to promote reforming reactions between the fuel vapor and exhaust gas to produce carbon monoxide and hydrogen gas, partial oxidation reactions between the fuel vapor and air to produce carbon monoxide and hydrogen gas, or direct hydrogen and carbon particle production from the fuel vapor. The plasma can be a thermal plasma or a non-thermal plasma. The plasma can be produced in a plasma generating device which can be preheated by contact with at least a portion of the hot exhaust gas stream, thereby decreasing the power requirements of the plasma generating device.

  15. Transient loss of plasma from a theta pinch having an initially reversed magnetic field

    SciTech Connect

    Heidrich, J. E.

    1981-01-01

    The results of an experimental study of the transient loss of plasma from a 25-cm-long theta pinch initially containing a reversed trapped magnetic field are presented. The plasma, amenable to MHD analyses, was a doubly ionized helium plasma characterized by an ion density N/sub i/ = 2 x 10/sup 16/ cm/sup -3/ and an ion temperature T/sub i/ = 15 eV at midcoil and by N/sub i/ = 0.5 x 10/sup 16/ cm/sup -3/ and T/sub i/ = 6 eV at a position 2.5 cm beyond the end of the theta coil.

  16. Visual and Electrical Evidence Supporting a Two-Plasma Mechanism of Vacuum Breakdown Initiation

    SciTech Connect

    Castano-Giraldo, C. [University of Illinois, Urbana-Champaign; Aghazarian, Maro [ORNL; Caughman, John B [ORNL; Ruzic, D. N. [University of Illinois, Urbana-Champaign

    2012-01-01

    The energy available during vacuum breakdown between copper electrodes at high vacuum was limited using resistors in series with the vacuum gap and arresting diodes. Surviving features observed with SEM in postmortem samples were tentatively correlated with electrical signals captured during breakdown using a Rogowski coil and a high-voltage probe. The visual and electrical evidence is consistent with the qualitative model of vacuum breakdown by unipolar arc formation by Schwirzke [1, 2]. The evidence paints a picture of two plasmas of different composition and scale being created during vacuum breakdown: an initial plasma made of degassed material from the metal surface, ignites a plasma made up of the electrode material.

  17. Study of Unsteady Flow Actuation Produced by Surface Plasma Actuator on 2-D Airfoil

    NASA Astrophysics Data System (ADS)

    Phan, Minh Khang; Shin, Jichul

    2014-10-01

    Effect of flow actuation driven by low current continuous or pulsed DC surface glow discharge plasma actuator is studied. Schlieren image of induced flow on flat plate taken at a high repetition rate reveals that the actuation is mostly initiated near the cathode. Assuming that the actuation is mostly achieved by ions in the cathode sheath region, numerical model for the source of flow actuation is obtained by analytical estimation of ion pressure force created in DC plasma sheath near the cathode and added in momentum equation as a body force term. Modeled plasma flow actuator is simulated with NACA0012 airfoil oscillating over a certain range of angle of attack (AoA) at specific reduced frequencies of airfoil. By changing actuation authority according to the change in AoA, stabilization of unsteady flow field is improved and hence steady aerodynamic performance can be maintained. Computational result shows that plasma actuation is only effective in modifying aerodynamic characteristics of separated flow. It turns out that plasma pulse frequency should be tuned for optimal performance depending on phase angle and rotating speed. The actuation authority can be parameterized by a ratio between plasma pulse frequency and reduced frequency.

  18. Using Plasma-Activated High Performance Fibers with Nanocrystalline Structure in Producing New Reinforced Composite Materials

    NASA Astrophysics Data System (ADS)

    Kudinov, V.; Korneeva, N.

    2008-08-01

    A wet-pull-out method for investigation of interaction between the high performance polyethylene (HPPE) fiber and polymer matrix is discussed. The paper concerns a cold plasma technique for improving the bond of the HPPE fibers to the matrices and the fibers impregnation with the matrix. Controlled parameters are pull-out force and the height of the matrix capillary lifting along the fiber both in air and in vacuum, in combination with plasma activation of the fibers. The method allows one to estimate the wetting and impregnation of multi-filament fiber with the matrix and simultaneously measure the joint strength. Coupled action of plasma treatment and vacuum impregnation of the fibers improves the joint strength by a factor of 3. Plasma activated HPPE fibers impregnated in air show the value of shear strength ? of 4 Kg/mm2. To understand the effect of treatment initial and plasma-activated fibers were used to fabricate composite materials (CM). The properties and failure modes were compared to those of CM reinforced with untreated fibers. The failure mode of CM reinforced with plasma-activated fibers points to a high strength of the bond between the fibers and the matrix.

  19. System to continuously produce carbon fiber via microwave assisted plasma processing

    DOEpatents

    White, Terry L. (Knoxville, TN) [Knoxville, TN; Paulauskas, Felix L. (Knoxville, TN) [Knoxville, TN; Bigelow, Timothy S. (Knoxville, TN) [Knoxville, TN

    2010-11-02

    A system to continuously produce fully carbonized or graphitized carbon fibers using microwave-assisted plasma (MAP) processing comprises an elongated chamber in which a microwave plasma is excited in a selected gas atmosphere. Fiber is drawn continuously through the chamber, entering and exiting through openings designed to minimize in-leakage of air. There is a gradient of microwave power within the chamber with generally higher power near where the fiber exits and lower power near where the fiber enters. Polyacrylonitrile (PAN), pitch, or any other suitable organic/polymeric precursor fibers can be used as a feedstock for the inventive system. Oxidized or partially oxidized PAN or pitch or other polymeric fiber precursors are run continuously through a MAP reactor in an inert, non-oxidizing atmosphere to heat the fibers, drive off the unwanted elements such as oxygen, nitrogen, and hydrogen, and produce carbon or graphite fibers faster than conventionally produced carbon fibers.

  20. Initial plasma of a magnetically insulated ion diode in bipolar-pulse mode

    SciTech Connect

    Xin, J. P.; Zhu, X. P.; Lei, M. K. [Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China)

    2008-12-15

    Initial anode plasma formation in a magnetically insulated ion diode (MID) of bipolar-pulse mode with self-magnetic field is studied for high-intensity pulsed ion beam generation in TEMP-6-type apparatus [X. P. Zhu, M. K. Lei, and T. C. Ma, Rev. Sci. Instrum. 73, 1728 (2002)]. The field emission characteristics on graphite anode, the self-magnetic field, the perveance, and the impedance of the MID are obtained by analysis of the time-dependent diode voltage-current characteristics during the initial negative pulse stage of 100 ns, with peak values of 250 kV and 30 kA, respectively. The anode plasma is initiated by explosive emission on the anode due to a significant field enhancement effect up to four orders of magnitude, and the subsequent merging and movement of the anode plasma are affected by the superimposing space-charge effect and magnetic insulation of the self-magnetic field. The formation process of the initial anode plasma in the MID corresponds to the diode response under the initial negative pulse of the bipolar pulse.

  1. The rapidly evolving field of decadal climate prediction, using initialized climate models to produce time-evolving predictions of regional climate, is producing new results for

    E-print Network

    The rapidly evolving field of decadal climate prediction, using initialized climate models to produce time-evolving predictions of regional climate, is producing new results for predictions, predictability, and prediction skill. DECADAL CLIMATE PREDICTION An Update from the Trenches by Gerald a. Meehl

  2. The diagnostics of ultra-short pulse laser-produced plasma

    NASA Astrophysics Data System (ADS)

    Roth, Markus

    2011-09-01

    Since the invention of the laser, coherent light has been used to break down solid or gaseous material and transform it into a plasma. Over the last three decades two things have changed. Due to multiple advancements and design of high power lasers it is now possible to increase the electric and magnetic field strength that pushed the electron motion towards the regime of relativistic plasma physics. Moreover, due to the short pulse duration of the driving laser the underlying physics has become so transient that concepts like thermal equilibrium (even a local one) or spatial isotropy start to fail. Consequently short pulse laser-driven plasmas have become a rich source of new phenomena that we are just about beginning to explore. Such phenomena, like particle acceleration, nuclear laser-induced reactions, the generation of coherent secondary radiation ranging from THz to high harmonics and the production of attosecond pulses have excited an enormous interest in the study of short pulse laser plasmas. The diagnostics of such ultra-short pulse laser plasmas is a challenging task that involves many and different techniques compared to conventional laser-produced plasmas. While this review cannot cover the entire field of diagnostics that has been developed over the last years, we will try to give a summarizing description of the most important techniques that are currently being used.

  3. Studies of extreme ultraviolet emission from laser produced plasmas, as sources for next generation lithography

    NASA Astrophysics Data System (ADS)

    Cummins, Thomas

    The work presented in this thesis is primarily concerned with the optimisation of extreme ultraviolet (EUV) photoemission around 13.5 nm, from laser produced tin (Sn) plasmas. EUV lithography has been identified as the leading next generation technology to take over from the current optical lithography systems, due to its potential of printing smaller feature sizes on integrated circuits. Many of the problems hindering the implementation of EUV lithography for high volume manufacturing have been overcome during the past 20 years of development. However, the lack of source power is a major concern for realising EUV lithography and remains a major roadblock that must be overcome. Therefore in order to optimise and improve the EUV emission from Sn laser plasma sources, many parameters contributing to the make-up of an EUV source are investigated. Chapter 3 presents the results of varying several different experimental parameters on the EUV emission from Sn laser plasmas. Several of the laser parameters including the energy, gas mixture, focusing lens position and angle of incidence are changed, while their effect on the EUV emission is studied. Double laser pulse experiments are also carried out by creating plasma targets for the main laser pulse to interact with. The resulting emission is compared to that of a single laser pulse on solid Sn. Chapter 4 investigates tailoring the CO2 laser pulse duration to improve the efficiency of an EUV source set-up. In doing so a new technique for shortening the time duration of the pulse is described. The direct effects of shortening the CO2 laser pulse duration on the EUV emission from Sn are then studied and shown to improve the efficiency of the source. In Chapter 5 a new plasma target type is studied and compared to the previous dual laser experiments. Laser produced colliding plasma jet targets form a new plasma layer, with densities that can be optimised for re-heating with the main CO2 laser pulse. Chapter 6 will present some experiments carried out on laser produced gadolinium plasmas, with its photoemission around 6.7 nm seen as a potential beyond EUV source. Three different laser pulse durations and a range of laser intensities are utilised in experiments to try to optimise the in-band emission, while also observing the effect on ion emission from the plasma. Finally, the experiments presented in thesis and their results are summarised in Chapter 7, along with presenting possible future work.

  4. Directional elliptically polarized terahertz emission from air plasma produced by circularly polarized intense femtosecond laser pulses

    SciTech Connect

    Jahangiri, Fazel; Hashida, Masaki; Tokita, Shigeki; Sakabe, Shuji [Advanced Research Center for Beam Science, ICR, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan and Department of Physics, GSS, Kyoto University, Kitashirakawa, Sakyo, Kyoto 606-7501 (Japan); Nagashima, Takeshi; Hangyo, Masanori [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2011-10-17

    We have observed directional elliptically polarized terahertz (THz) waves emitted from air plasma produced by circularly polarized femtosecond laser pulses. The spatial distribution of the THz waves shows that the radiation is strongly directed forward with a peak around the laser propagation direction. Measured THz power shows a square dependence on laser energy. We consider the parametric decay of laser light to R-waves in plasma in the presence of a spontaneous magnetic field as a possible explanation for the polarization, power dependence, and direction of the THz beam.

  5. Superradiant Amplification in Laser Produced Plasma by KrF laser

    NASA Astrophysics Data System (ADS)

    Takahashi, Eiichi; Kato, Susumu; Owadano, Yoshiro

    2002-10-01

    Superradiant amplification (SRA) in laser produced plasmas by KrF laser system for the use of large pump energy is examined by one-dimensional particle in cell simulation code. Its ultra-violet laser wavelength has many advantages for SRA. The simulation code predicts that the required signal pulse width is shorter than 100fs for out supposed conditions if the seed signal pulse shape is gaussian. Transient Raman scattering wavelength conversion in gaseous media can create truncated leading edge pulse. The simulation code showed the pulse can form leading edge spike by the amplification in plasmas.

  6. Radiation-Hydrodynamics, Spectral, and Atomic Physics Modeling of Laser-Produced Plasma EUV Lithography Light Sources

    Microsoft Academic Search

    J. J. MacFarlane; C. L. Rettig; P. Wang; I. E. Golovkin; P. R. Woodruff

    Tin, lithium, and xenon laser-produced plasmas are attractive candidates as light sources for extreme ultraviolet lithography (EUVL). Simulation of the dynamics and spectral properties of plasmas created in EUVL experiments plays a crucial role in analyzing and interpreting experimental measurements, and in optimizing the 13.5 nm radiation from the plasma source. Developing a good understanding of the physical processes in

  7. Investigation of a Gas Jet-Produced Hollow Plasma Wakefield Accelerator

    SciTech Connect

    Kirby, N; Blumenfeld, I.; Hogan, M.J.; Siemann, R.H.; Walz, D.R.; /SLAC; Davidson, A.W.; Huang, C.; /UCLA

    2009-05-21

    The effect of ion motion and the need for practical positron propagation in a plasma wakefield accelerator (PWFA) have incited interest in hollow plasma channels. These channels are typically assumed to be cylindrically symmetric; however, a different geometry might be easier to achieve. The introduction of an obstruction into the outlet of a high Mach number gas jet can produce two parallel slabs of gas separated by a density depression. Here, there is a detailed simulation study of the density depression created in such a system. This investigation reveals that the density depression is insufficient at the desired plasma density. However, insights from the simulations suggest another avenue for the creation of the hollow slab geometry.

  8. Application of electrostatic Langmuir probe to atmospheric arc plasmas producing nanostructures

    NASA Astrophysics Data System (ADS)

    Shashurin, A.; Li, J.; Zhuang, T.; Keidar, M.; Beilis, I. I.

    2011-07-01

    The temporal evolution of a high pressure He arc producing nanotubes was considered and the Langmuir probe technique was applied for plasma parameter measurements. Two modes of arc were observed: cathodic arc where discharge is supported by erosion of cathode material and anodic arc which is supported by ablation of the anode packed with carbon and metallic catalysts in which carbon nanotubes are synthesized. Voltage-current (V-I) characteristics of single probes were measured and unusually low ratio of saturation current on positively biased probe to that on negatively biased of about 1-4 was observed. This effect was explained by increase of measured current at the negatively biased probe above the level of ion saturation current due to secondary electron emission from the probe surface. Since utilization of standard collisionless approach to determine plasma parameters from the measured V-I characteristic is not correct, the electron saturation current was used to estimate the plasma density.

  9. Photopumping and fluorescence in a laser-produced plasma. I. Experimental results

    NASA Astrophysics Data System (ADS)

    Back, C. A.; Chenais-Popovics, C.; Lee, R. W.

    1991-11-01

    A complete series of three experiments dedicated to the study of a photopumping and resonance fluorescence scheme is presented. An aluminum plasma is preformed in the heliumlike ground state by a 2-J 1.06-?m laser beam, then this plasma is photopumped by an x-ray source ~1 ns later. The pump is a spatially distinct laser-produced plasma that emits intense emission of the heliumlike resonance lines in the 4-8- region. The pump is line coincident with the transitions to be photopumped. The resulting perturbation is studied by the fluorescence, which is directly observed and absolutely quantified. The separate characterization of each component of this system is discussed in detail, with an emphasis on the experimental quantities that will be compared with numerical calculations.

  10. A comparison of kinetic and multifluid simulations of laser-produced colliding plasmas

    SciTech Connect

    Rambo, P.W.; Procassini, R.J. [University of California, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)] [University of California, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)

    1995-08-01

    The amount of interpenetration and stagnation in counterstreaming laser-produced plasmas is investigated via a kinetic model and a multifluid model in one-dimensional planar geometry. Each of these models can evolve multiple ion species in the self-consistent electrostatic field with Coulomb collisional interaction. The two approaches are applied to various colliding plasma systems, ranging from simple homogeneous slowing-down and temperature-equilibration problems to colliding plasmas characteristic of laser irradiated thin foils and thick disks. In particular, direct comparisons are made between the kinetic formulation and the multifluid model with various approximations for the multifluid collisional coupling coefficients. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  11. The reflection of an electromagnetic wave from the self-produced plasma

    SciTech Connect

    Mirzaie, M. [Department of Physics, Shahid Beheshti University, G. C., Evin, 1983963113 Tehran (Iran, Islamic Republic of); Shokri, B. [Department of Physics and Laser-Plasma Research Inst., Shahid Beheshti University, G. C., Evin, 1983963113 Tehran (Iran, Islamic Republic of); Rukhadze, A. A. [General Physics Institute, 38-117942 Vavilova St., Moscow (Russian Federation)

    2010-01-15

    The dynamic behavior of a high power microwave beam propagating through a gaseous medium, which is ionized in the wave field is investigated. By solving the wave equation, the reflection index of the produced plasma is obtained. It is shown that the cut off condition is different from that of the steady state approximation. The reflection index is less than unity when the plasma density reaches the critical value estimated in the steady state approximation. So, the wave can still propagate through the plasma. By comparing the reflection indexes in the presence and absence of the time delay of the ionization process at different points of the medium, it is shown that it becomes unity much later in the first case. Therefore, the wave propagation takes much more time and consequently the medium is ionized much more.

  12. Temporal characteristics of backscattered light from a KrF laser-produced plasma

    SciTech Connect

    Fujita, M.; Offenberger, A.A.; Capjack, C.E. (Department of Electrical Engineering, University of Alberta, Edmonton, Alberta, T6G 2G7 (Canada))

    1994-09-01

    We report measurements of the time-resolved spectra of backscattered light, near the incident laser wavelength (0.25 [mu]m), from aluminum plasmas produced by nanosecond pulse KrF laser radiation at an intensity [congruent]10[sup 14] W/cm[sup 2]. The redshifted scattered light shows the characteristic temporal and spectral features of stimulated Brillouin scattering. The observed spectral linewidth ([congruent]0.3 A) can be accounted for by inhomogeneity in the plasma flow velocity and density. The experimental results are compared with model predictions of the spectral shift using a two-dimensional hydrodynamic simulation computer code (CASTOR). The dynamics of the spectral shift show a strong correlation with the laser pulse shape, indicating the importance of inverse bremsstrahlung absorption for short wavelength laser radiation and heat transport in a highly collisional plasma.

  13. Diamond Like Carbon Coating Produced by Plasma Source Ion Implantation as a Corrosion Barrier for Steels in Marine Environments

    E-print Network

    Diamond Like Carbon Coating Produced by Plasma Source Ion Implantation as a Corrosion Barrier Laboratory Los Alamos, NM 87545 June 20, 1997 Abstract A36 steel samples coated with diamond like carbon (DLC) produced by plasma source ion implantation (PSII) were examined in ASTM artificial ocean water (ASTM AOW

  14. Enhancement of x-ray line emission from plasmas produced by short high-intensity laser double pulses

    E-print Network

    Limpouch, Jiri

    Enhancement of x-ray line emission from plasmas produced by short high-intensity laser double laser-produced plasmas are bright ultrafast line x-ray sources potentially suitable for different onto a solid target into the x-ray emission is significantly enhanced when a laser prepulse precedes

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

    SciTech Connect

    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.

  16. Numerical modeling of initiation of lightning leaders from tall structures by sprite-producing lightning discharges

    NASA Astrophysics Data System (ADS)

    Pasko, V. P.

    2011-12-01

    It is well established by now that large charge transfers between cloud and ground in positive cloud-to-ground lightning discharges (+CGs) can lead to transient electric field enhancements at mesospheric and lower ionospheric altitudes. In these events the electric field can exceed the conventional breakdown field and lead to formation of transient luminous events referred to as sprites and sprite halos [e.g., Qin et al., JGR, 116, A06305, 2011, and references therein]. Stanley and Heavner [Proc. 12th International Conference on Atmospheric Electricity, Versailles, France, 2003] reported that the large and rapid charge transfer of +CGs producing sprites can also initiate upward positive leaders from tall structures. These authors also presented data analysis indicating that structures with >400 m height have a significantly enhanced probability of launching upward positive leaders that may culminate in a -CG return stroke to the structure. The effect can be understood by considering the field intensification at the top of the tall structure combined with fast application of the field preventing formation and shielding effects of ion corona [Brook et al., JGR, 66, 3967, 1961]. In the present work we utilize the most recent modeling approaches developed at Penn State [e.g., Riousset et al., JGR, 115, A00E10, 2010] to quantify the conditions leading to initiation of positive leaders from tall structures following sprite-producing +CGs. Experiments show that the streamer zone transforms into leader when voltage drop along the streamer zone exceeds 400 kV [e.g., Aleksandrov et al., J. Phys. D: Appl. Phys., 38, 1225, 2005]. For a formed leader half of the voltage drops in the streamer zone, and another half in free space ahead of the streamer zone [Bazelyan and Raizer, Lightning physics and lightning protection, p. 62, 2000]. In our analysis therefore we assume that minimum voltage at the tip of the tower should exceed 800 kV for sustainment of upward propagating leader. The results indicate, in particular, that a charge moment change of 390 C km in a +CG can lead to leader initiation from a 457 m tower approximately 15 km from the +CG, in good agreement with observations reported in [Stanley and Heavner, 2003]. We report detailed relationships, including analytical estimates and numerical modeling results, providing information on the charge moment charges versus tower height and radial position with respect to +CG required for initiation of upward leaders.

  17. Pilot scale test of a produced water-treatment system for initial removal of organic compounds

    SciTech Connect

    Sullivan, Enid J [Los Alamos National Laboratory; Kwon, Soondong [UT-AUSTIN; Katz, Lynn [UT-AUSTIN; Kinney, Kerry [UT-AUSTIN

    2008-01-01

    A pilot-scale test to remove polar and non-polar organics from produced water was performed at a disposal facility in Farmington NM. We used surfactant-modified zeolite (SMZ) adsorbent beds and a membrane bioreactor (MBR) in combination to reduce the organic carbon content of produced water prior to reverse osmosis (RO). Reduction of total influent organic carbon (TOC) to 5 mg/L or less is desirable for efficient RO system operation. Most water disposed at the facility is from coal-bed gas production, with oil production waters intermixed. Up to 20 gal/d of produced water was cycled through two SMZ adsorbent units to remove volatile organic compounds (BTEX, acetone) and semivolatile organic compounds (e.g., napthalene). Output water from the SMZ units was sent to the MBR for removal of the organic acid component of TOC. Removal of inorganic (Mn and Fe oxide) particulates by the SMZ system was observed. The SMZ columns removed up to 40% of the influent TOC (600 mg/L). BTEX concentrations were reduced from the initial input of 70 mg/L to 5 mg/L by the SMZ and to an average of 2 mg/L after the MBR. Removal rates of acetate (input 120-170 mg/L) and TOC (input up to 45 mg/L) were up to 100% and 92%, respectively. The water pH rose from 8.5 to 8.8 following organic acid removal in the MBR; this relatively high pH was likely responsible for observed scaling of the MBR internal membrane. Additional laboratory studies showed the scaling can be reduced by metered addition of acid to reduce the pH. Significantly, organic removal in the MBR was accomplished with a very low biomass concentration of 1 g/L throughout the field trial. An earlier engineering evaluation shows produced water treatment by the SMZ/MBR/RO system would cost from $0.13 to $0.20 per bbl at up to 40 gpm. Current estimated disposal costs for produced water are $1.75 to $4.91 per bbl when transportation costs are included, with even higher rates in some regions. Our results suggest that treatment by an SMZ/MBR/RO system may be a feasible alternative to current methods for produced water treatment and disposal.

  18. High-quality electron beam from laser wake-field acceleration in laser produced plasma plumes

    SciTech Connect

    Sanyasi Rao, Bobbili; Moorti, Anand; Rathore, Ranjana; Ali Chakera, Juzer; Anant Naik, Prasad; Dass Gupta, Parshotam [Laser Plasma Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)] [Laser Plasma Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)

    2013-06-10

    Generation of highly collimated ({theta}{sub div}{approx}10 mrad), quasi-monoenergetic electron beam with peak energy 12 MeV and charge {approx}50 pC has been experimentally demonstrated from self-guided laser wake-field acceleration (LWFA) in a plasma plume produced by laser ablation of solid nylon (C{sub 12}H{sub 22}N{sub 2}O{sub 2}){sub n} target. A 7 TW, 45 fs Ti:sapphire laser system was used for LWFA, and the plasma plume forming pulse was derived from the Nd:YAG pump laser of the same system. The results show that a reproducible, high quality electron beam could be produced from this scheme which is simple, low cost and has the capability for high repetition rate operation.

  19. Astrophysics of magnetically collimated jets generated from laser-produced plasmas.

    PubMed

    Ciardi, A; Vinci, T; Fuchs, J; Albertazzi, B; Riconda, C; Ppin, H; Portugall, O

    2013-01-11

    The generation of astrophysically relevant jets, from magnetically collimated, laser-produced plasmas, is investigated through three-dimensional, magnetohydrodynamic simulations. We show that for laser intensities I?10(12)-10(14)?W?cm(-2), a magnetic field in excess of ?0.1??MG, can collimate the plasma plume into a prolate cavity bounded by a shock envelope with a standing conical shock at its tip, which recollimates the flow into a supermagnetosonic jet beam. This mechanism is equivalent to astrophysical models of hydrodynamic inertial collimation, where an isotropic wind is focused into a jet by a confining circumstellar toruslike envelope. The results suggest an alternative mechanism for a large-scale magnetic field to produce jets from wide-angle winds. PMID:23383908

  20. Pressure-driven, resistive magnetohydrodynamic interchange instabilities in laser-produced high-energy-density plasmas.

    PubMed

    Li, C K; Frenje, J A; Petrasso, R D; Sguin, F H; Amendt, P A; Landen, O L; Town, R P J; Betti, R; Knauer, J P; Meyerhofer, D D; Soures, J M

    2009-07-01

    Recent experiments using proton backlighting of laser-foil interactions provide unique opportunities for studying magnetized plasma instabilities in laser-produced high-energy-density plasmas. Time-gated proton radiograph images indicate that the outer structure of a magnetic field entrained in a hemispherical plasma bubble becomes distinctly asymmetric after the laser turns off. It is shown that this asymmetry is a consequence of pressure-driven, resistive magnetohydrodynamic (MHD) interchange instabilities. In contrast to the predictions made by ideal MHD theory, the increasing plasma resistivity after laser turn-off allows for greater low-mode destabilization (m>1) from reduced stabilization by field-line bending. For laser-generated plasmas presented herein, a mode-number cutoff for stabilization of perturbations with m> approximately [8pibeta(1+D_{m}k_{ perpendicular};{2}gamma_{max};{-1})];{1/2} is found in the linear growth regime. The growth is measured and is found to be in reasonable agreement with model predictions. PMID:19658823

  1. Analysis of dust particles produced due to interaction between graphite and deuterium helicon plasmas

    NASA Astrophysics Data System (ADS)

    Iwashita, Shinya; Koga, Kazunori; Shiratani, Masaharu

    2008-10-01

    Formation mechanisms of dust particles due to interaction between carbon walls and plasmas in fusion devices have attracted considerable attention, because they pose two potential problems: they can contain a large amount of tritium and their existence in fusion devices may lead to deterioration of plasma confinement. To obtain information on formation mechanisms of dust particles of nm in size in fusion devices, we have generated deuterium helicon discharge plasmas which simulate divertor plasmas in fusion devices and then we have collected and analyzed dust particles produced due to interaction between graphite and the plasmas. Dust particles are made of carbon and can be classified into three kinds: small dust particles below 1 ?m in size, large flakes above 1 ?m in size, and agglomerates which consist of primary particles of 10 nm. These three kinds suggest three formation mechanisms, that is, CVD growth, carbon films peeled from walls, and agglomeration [1]. There exist a large number of small dust particles below 1 ?m in size. All of these features are quite close to those of dust particles collected during the main discharges of LHD. [1] Y. Watanabe, et al. J. Vac. Sci. Technol., A14, 540 (1996).

  2. Single films and heat mirrors produced by plasma ion assisted deposition

    Microsoft Academic Search

    J. K. Fu; G. Atanassov; Y. S. Dai; F. H. Tan; Z. Q. Mo

    1997-01-01

    Single TiO2, MgF2, Ag and TiN thin films and heat mirrors are produced by plasma ion assisted deposition (PIAD) in a vacuum system (Leybold APS 904). Experimental results for the optical properties, stress and topography are reported. The obtained refractive indices at wavelength 550 nm of both TiO2 and MgF2 thin films deposited by PIAD are 2.40 0.02 and

  3. Measurement of density-sensitive electric quadrupole transitions in neonlike laser-produced plasmas

    SciTech Connect

    Young, B.K.F.; Osterheld, A.L.; Walling, R.S.; Goldstein, W.H.; Phillips, T.W.; Stewart, R.E.; Charatis, G.; Busch, G.E.

    1989-03-13

    We report on the measurement of density-sensitive electric quadrupole transitions in neonlike molybdenum and silver laser-produced plasmas. These observations are unique in that they represent data which are simultaneously space and time resolved. The electron densities were determined using holographic interferometry. We test the predicted density sensitivity of the electric quadrupole transitions and find excellent agreement with calculations using a detailed, steady-state, collisional-radiative model of the neonlike charge state.

  4. Observation of laser satellites in a plasma produced by a femtosecond laser pulse

    Microsoft Academic Search

    S. A. Pikuz; A. Maksimchuk; D. Umstadter; M. Nantel; I. Yu. Skobelev; A. Ya. Faenov; A. Osterheld

    1997-01-01

    Laser satellites are detected in the emission spectra of magnesium and aluminum plasmas produced by femtosecond laser pulses.\\u000a This is made possible by the realization of picosecond time resolution in a high-luminosity x-ray spectrograph with a spherically\\u000a curved mica crystal. The temporal characteristics of these newly recorded spectral lines show unequivocally that they are\\u000a formed as a result of nonlinear

  5. Instabilities in self-focused electron beams. [produced by self-generated plasma

    NASA Technical Reports Server (NTRS)

    Gibson, R. A.; Bennett, W. H.

    1974-01-01

    The appearance of large amplitude oscillations and attenuation of beam current have been observed in high perveance electrically self-focused beams. These phenomena are shown to be due to instabilities produced by the interaction of the beam with its self-generated plasma. The critical current which must be exceeded for the instabilities to appear and the frequencies of the oscillations have been related to beam and background parameters and the dimensions of the experimental system.

  6. Spectra of Mo XXX, XXXI, and XXXII from a laser-produced plasma

    Microsoft Academic Search

    P. G. Burkhalter; Joseph Reader; Robert D. Cowan

    1977-01-01

    Spectra of highly charged Mo ions generated in a laser-produced plasma were observed from 10 to 190 A with a 3 m grazing- incidence spectrograph. Line identifications in Mo XXX-- XXXII were made with the help of relativistic Hartree-Fock calculations. In Mo XXXI (Mg-like) the 3s² ¹S--3s3p ¹P resonance line was found to be at 115.944 A. In Mo XXXII

  7. Measurements of radial heat wave propagation in laser-produced exploding-foil plasmas

    Microsoft Academic Search

    D. S. Montgomery; O. L. Landen; R. P. Drake; K. G. Estabrook; H. A. Baldis; S. H. Batha; K. S. Bradley; R. J. Procassini

    1994-01-01

    Time-resolved, 2D images of x-ray emission from thin, laser-irradiated titanium foils are presented. The foils are irradiated with 0.35 mum light at intensities of 11015 W\\/cm2 which produces a plasma with electron densities <=1022 cm-3 and electron temperature of 3-4 keV. X-ray emission that is characteristic of the thermal heat front is observed to propagate radially outward from the heated

  8. Self-generated magnetic fields in laser-produced plasmas for metallic targets

    Microsoft Academic Search

    D. F. Edwards; V. V. Korobkin; S. L. Motilev; R. V. Serov

    1977-01-01

    Direct experimental evidence obtained at magnetic-field intensities of 1000 G or less is reported which indicates that the self-generated magnetic field associated with the laser-produced plasma from metal targets (iron, copper, aluminum) consists of two identifiable components having different radial and background pressure dependences as well as different propagation rates. Two independent temporal rates of change in magnetic induction are

  9. Analysis of the x-ray spectrum emitted by laser-produced plasma of dysprosium

    SciTech Connect

    Marcus, Gilad; Louzon, Einat; Henis, Zohar; Maman, Shlomo; Mandelbaum, Pinchas [Soreq Research Center, 81800 Yavne (Israel); Jerusalem College of Engineering, Ramat Beth Hakerem, 91035 Jerusalem (Israel)

    2007-05-15

    A detailed analysis of the x-ray spectrum (5-10.2 A ring ) emitted by laser-produced plasma of dysprosium (Dy) is given using ab initio calculations with the HULLAC relativistic code and isoelectronic trends. Resonance 3d-4p, 3d-nf (n=4 to 7), 3p-4s, and 3p-4d transitions of Ni I-like Dy XXXIX and neighboring ion satellite transitions (from Dy XXXIV to Dy XL) are identified.

  10. Sub-keV, subnanosecond measurements of X-ray spectra from laser-produced plasmas

    Microsoft Academic Search

    H. N. Kornblum; L. N. Koppel; V. W. Livinsky; S. S. Glaros; H. G. Ahlstrom; J. T. Larsen

    1977-01-01

    X-ray spectral measurements of laser-produced plasmas were made for photon energies down to 100 eV with a time response of 0.5 nsec. Fast, windowless X-ray diodes were used in conjunction with critical angle reflecting mirrors and thin filters for energy definition for two channels 300 to 600 eV and 800 to 1300 eV. A third channel, using only an X-ray

  11. Measurement of electron density utilizing the H ?-line from laser produced plasma in air

    Microsoft Academic Search

    A. M. El Sherbini; H. Hegazy; Th. M. El Sherbini

    2006-01-01

    The electron density in a laser produced plasma experiment was measured utilizing the Stark broadening of the H?-line at 656.27nm. This line results from the interaction of the Nd:YAG laser at the fundamental wavelength of 1.06?m with a plane solid aluminum target in a humid air. The measurements were repeated at several delay times (010?s) and at a fixed gate

  12. TiB\\/sub 2\\/Cu interpenetrating phase composites produced by spark-plasma sintering

    Microsoft Academic Search

    Dina V. Dudina; Oleg I. Lomovsky; Michail A. Korchagin; Young-Soon Kwon

    2003-01-01

    Interpenetrating phase composites of TiB\\/sub 2\\/-Cu system were produced via spark-plasma sintering (SPS) of nanocomposite powders. Under simultaneous action of pressure, temperature and electric current the titanium diboride nanoparticles distributed in copper matrix move, agglomerate and form a fine-grained skeleton. Increasing SPS-temperature and holding time promote densification due to local melting of copper matrix. When copper melting is avoided, the

  13. Laser-produced plasma EUV source using a colloidal microjet target containing tin dioxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Higashiguchi, Takeshi; Dojyo, Naoto; Sasaki, Wataru; Kubodera, Shoichi

    2006-10-01

    We realized a low-debris laser-produced plasma extreme ultraviolet (EUV) source by use of a colloidal microjet target, which contained low-concentration (6 wt%) tin-dioxide nanoparticles. An Nd:YAG laser was used to produce a plasma at the intensity on the order of 10^11 W/cm^2. The use of low concentration nanoparticles in a microjet target with a diameter of 50 ?m regulated the neutral debris emission from a target, which was monitored by a silicon witness plate placed 30 cm apart from the source in a vacuum chamber. No XPS signals of tin and/or oxygen atoms were observed on the plate after ten thousand laser exposures. The low concentration nature of the target was compensated and the conversion efficiency (CE) was improved by introducing double pulses of two Nd:YAG lasers operated at 532 and 1064 nm as a result of controlling the micro-plasma characteristics. The EUV CE reached its maximum of 1.2% at the delay time of approximately 100 ns with the main laser intensiy of 2 x10^11 W/cm^2. The CE value was comparable to that of a tin bulk target, which, however, produced a significant amount of neutral debris.

  14. PLASMA CELL NEOPLASIA IN A SINGLE HOST: A MOSAIC OF DIFFERENT PROTEIN-PRODUCING CELL TYPES

    PubMed Central

    Potter, Michael

    1962-01-01

    The peritoneal plasma cell neoplasias that develop in strain BALB/c mice after the injection of adjuvant-staphylococcus mixtures or mineral oil alone appear in the form of multiple nodules in the mesentery and on peritoneal surfaces. Experiments were done to determine if these nodules were metastases or multiple primary neoplasms. Nodules or pieces of masses were transplanted subcutaneously by the trochar method or by insertion of tissue under the kidney capsule from 6 primary cases and parallel transplant lines were established. The serum and urinary protein abnormality (a stable heritable characteristic) of each of the various transplant lines was characterized by agar gel electrophoresis and immunoelectrophoresis. Different protein-producing lines were found in 3 cases; in one case 5 different protein-producing lines were isolated. Two different lines were found for each of the other 2 cases. When transplantation studies were begun early, it was demonstrated that the nodules were multiple primary plasma cell neoplasms; when delayed, only one protein-producing plasma cell neoplasm was found. PMID:14488298

  15. ELM simulation experiments using transient heat and particle load produced by a magnetized coaxial plasma gun

    NASA Astrophysics Data System (ADS)

    Shoda, K.; Sakuma, I.; Iwamoto, D.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

    2011-10-01

    It is considered that thermal transient events such as type I edge-localized modes (ELMs) and disruptions will limit the lifetime of plasma-facing components (PFCs) in ITER. It is predicted that the heat load onto the PFCs during type I ELMs in ITER is 0.2-2MJ/m2 with pulse length of ~0.1-1ms. We have investigated interaction between transient heat and particle load and the PFCs by using a magnetized coaxial plasma gun (MCPG) at University of Hyogo. In the experiment, a pulsed plasma with duration of ~0.5ms, incident ion energy of ~30eV, and surface absorbed energy density of ~0.3-0.7MJ/m2 was produced by the MCPG. However, no melting occurred on a tungsten surface exposed to a single plasma pulse of ~0.7MJ/m2, while cracks clearly appeared at the edge part of the W surface. Thus, we have recently started to improve the performance of the MCPG in order to investigate melt layer dynamics of a tungsten surface such as vapor cloud formation. In the modified MCPG, the capacitor bank energy for the plasma discharge is increased from 24.5 kJ to 144 kJ. In the preliminary experiments, the plasmoid with duration of ~0.6 ms, incident ion energy of ~ 40 eV, and the surface absorbed energy density of ~2 MJ/m2 was successfully produced at the gun voltage of 6 kV.

  16. The determination of parameters of recombining laser-produced plasmas by means of X-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Boiko, V. A.; Faenov, A. Ia.; Hachalin, S. Ia.; Pikuz, S. A.; Shilov, K. A.; Skobelev, I. Iu.

    1983-02-01

    The investigation of expanding laser-produced plasmas has been carried out. X-ray spectra of multicharged F VIII and F IX ions were observed in the wavelength range of 11-17 A for the regions of expanding plasma, remote from the target surface by up to 10 mm. The calculations of resonance and intercombination line relative intensities were made, taking into account recombination of the population of ion levels in the case of sharply nonequilibrium plasma ionization states. The results of the calculation are utilized for an investigation of expanding laser-produced fluorine plasmas.

  17. Start broadened profiles with self-consistent radiation transfer and atomic kinetics in plasmas produced by high intensity lasers

    SciTech Connect

    Olson, G.L.; Comly, J.C.; La Gattuta, J.K.; Kilcrease, D.P.

    1993-03-01

    Spectral line shapes and line strengths have long been used to diagnose plasma temperatures and densities. In dense plasmas, the additional broadening due to Stark effects give additional information about the plasma density. We present calculations that are self-consistent in that the radiation fields of the line transitions and the atomic kinetics are iterated to convergence. Examples are given for simple plasmas with temperature gradients, density gradients, and velocity fields. Then a more complex example of a laser produced plasma is presented.

  18. Start broadened profiles with self-consistent radiation transfer and atomic kinetics in plasmas produced by high intensity lasers

    SciTech Connect

    Olson, G.L.; Comly, J.C.; La Gattuta, J.K.; Kilcrease, D.P.

    1993-01-01

    Spectral line shapes and line strengths have long been used to diagnose plasma temperatures and densities. In dense plasmas, the additional broadening due to Stark effects give additional information about the plasma density. We present calculations that are self-consistent in that the radiation fields of the line transitions and the atomic kinetics are iterated to convergence. Examples are given for simple plasmas with temperature gradients, density gradients, and velocity fields. Then a more complex example of a laser produced plasma is presented.

  19. Theory of Raman sidescattering for a laser-produced plasma with an exponential density profile

    SciTech Connect

    Kutty, A.P.G.; Sinha, B.K.

    1986-04-01

    Equations for the stimulated Raman sidescattering from a laser-produced plasma with an exponential density profile have been derived. They have been solved by using the WKB method, and the resulting Bohr--Sommerfeld condition has been solved numerically for the growth rates of the absolute instability and the frequency shifts as a function of the laser intensity, the density gradient scale length, and the plasma frequency. The results have been discussed and compared with the previously reported work on the plasma with linear density profile. Instability growth rates are found to be nearly the same for both cases, except for very steep density profiles, for which the difference can become appreciable. The two theories, one of which considers a hot plasma, lead to significantly different frequency shifts. It is found that, for high laser powers, the instability persists even for very steep profiles. Furthermore, for such profiles the maximum of the growth rate occurs far away from the quarter critical layer, for moderately high power lasers.

  20. Laser-intensity scaling experiments in long-scalelength, laser-produced plasmas

    SciTech Connect

    Drake, R.P.; Young, P.E.; Williams, E.A.; Estabrook, K.; Kruer, W.L.; Lasinski, B.F.; Darrow, C.B.; Baldis, H.A.; Johnston, T.W.

    1988-06-01

    An experimental technique is demonstrated that allows variation of the average laser intensity by more than two orders of magnitude while producing much smaller changes in the other parameters that determine the laser--plasma interactions. By irradiating exploding-foil targets with 0.35 ..mu..m laser light in flat-topped pulses of variable duration, the high-power Nova laser (Rev. Sci. Instrum. 57, 2101 (1986)) produced plasmas with electron temperatures of order 1 keV and with scale lengths of the (radial and axial) electron-density gradients of order 1000 laser wavelengths. By using a constant target thickness and systematically decreasing the pulse length and spot size as laser intensity increased, the changes in the temperature and in the scale lengths were minimized. The time-resolved spectrum of the Raman-scattered light was used to measure both the electron temperature and the maximum density of the expanding plasmas. In this paper, these measurements are compared to both 1-D models and 2-D simulations. The expected trends of slower burnthrough and lower temperature with lower laser intensity were observed. However, the inferred temperatures are lower and the burnthrough of the target (at high laser intensities) is slower than the modeling predicts. Possible sources of these discrepancies are discussed.

  1. Kinetic effects and nonlinear heating in intense x-ray-laser-produced carbon plasmas

    NASA Astrophysics Data System (ADS)

    Sentoku, Y.; Paraschiv, I.; Royle, R.; Mancini, R. C.; Johzaki, T.

    2014-11-01

    The x-ray laser-matter interaction for a low-Z material, carbon, is studied with a particle-in-cell code that solves the photoionization and x-ray transport self-consistently. Photoionization is the dominant absorption mechanism and nonthermal photoelectrons are produced with energy near the x-ray photon energy. The photoelectrons ionize the target rapidly via collisional impact ionization and field ionization, producing a hot plasma column behind the laser pulse. The radial size of the heated region becomes larger than the laser spot size due to the kinetic nature of the photoelectrons. The plasma can have a temperature of more than 10 000 K (>1 eV ), an energy density greater than 104 J /cm3 , an ion-ion Coulomb coupling parameter ? ?1 , and electron degeneracy ? ?1 , i.e., strongly coupled warm dense matter. By increasing the laser intensity, the plasma temperature rises nonlinearly from tens of eV to hundreds of eV, bringing it into the high energy density matter regime. The heating depth and temperature are also controllable by changing the photon energy of the incident laser light.

  2. Kinetic effects and nonlinear heating in intense x-ray-laser-produced carbon plasmas.

    PubMed

    Sentoku, Y; Paraschiv, I; Royle, R; Mancini, R C; Johzaki, T

    2014-11-01

    The x-ray laser-matter interaction for a low-Z material, carbon, is studied with a particle-in-cell code that solves the photoionization and x-ray transport self-consistently. Photoionization is the dominant absorption mechanism and nonthermal photoelectrons are produced with energy near the x-ray photon energy. The photoelectrons ionize the target rapidly via collisional impact ionization and field ionization, producing a hot plasma column behind the laser pulse. The radial size of the heated region becomes larger than the laser spot size due to the kinetic nature of the photoelectrons. The plasma can have a temperature of more than 10000 K (>1eV), an energy density greater than 10^{4} J/cm^{3}, an ion-ion Coulomb coupling parameter ??1, and electron degeneracy ??1, i.e., strongly coupled warm dense matter. By increasing the laser intensity, the plasma temperature rises nonlinearly from tens of eV to hundreds of eV, bringing it into the high energy density matter regime. The heating depth and temperature are also controllable by changing the photon energy of the incident laser light. PMID:25493733

  3. Initial plasma disappearance and tissue uptake of 131I-albumin in normal rabbits

    SciTech Connect

    Bent-Hansen, L. (Department of Medicine B, Rigshospitalet, University of Copenhagen (Denmark))

    1991-05-01

    The simultaneous plasma disappearance curves of 131I-albumin and 125I-fibrinogen were recorded in normal rabbits for 1 hr. Using fibrinogen as a plasma reference, the disappearance curves of albumin were shown to contain two separate phases of efflux: one fast from zero to 10 min. comprising 8% of the total tracer; and one slow appearing in the interval of 10 to 60 min. containing another 9% of the tracer. Total albumin escape was analyzed to yield an initial slope of 0.024 {plus minus} 0.004 min-1, corresponding to a wholebody unidirectional albumin clearance (Cl(0)) of 0.090 {plus minus} 0.009 ml(min{asterisk}100 g)-1. The distribution of efflux was assessed by biopsy uptakes using the same tracers in spleen, kidney, heart, lung, liver, intestine, skin, muscle, and brain. The disappearance curve generally reflects a biphasic pattern of uptake in peripheral tissue, predominantly by muscle and lung. The rapid phase has contributions from the fast near equilibration of liver, and intestine and skin are significant codeterminants of the slow phase. Due to their low body masses highly perfused organs such as kidney, spleen, and heart have little influence on the plasma disappearance. In accordance, the Cl(0) determined for the wholebody was higher than initial clearances found in skin (0.053 ml(min{asterisk}100 g)-1) and muscle (0.054 ml(min{asterisk}100 g)-1), but much lower than those found in the highly perfused organs. The initial (unidirectional) rates of peripheral albumin transfer demonstrated, ranged from 10 to 30 times higher than estimates of lymphatic return, suggesting that transcapillary albumin exchange is mediated by high-rate bidirectional diffusion. The rapid decrease of net albumin exchange rates suggests a second, highly significant barrier located within the interstitial matrix, which restricts plasma escape and reduces plasma to lymph albumin transport.

  4. Supersonic propagation of ionization waves in an under-dense, laser-produced plasma

    SciTech Connect

    Constantin, C; Back, C A; Fournier, K B; Gregori, G; Landen, O L; Glenzer, S H; Dewald, E L; Miller, M C

    2004-10-22

    We observe a laser-driven supersonic ionization wave heating a mm-scale plasma of sub-critical density up to 2-3 keV electron temperatures. Propagation velocities initially 10 times the sound speed were measured by means of time-resolved x-ray imaging diagnostics. The measured ionization wave trajectory is modeled analytically and by a 2D radiation-hydrodynamics code. The comparison to the modeling suggests that nonlocal heat transport effects may contribute to the attenuation of the heat wave propagation.

  5. Emission spectroscopy studies of volatile species produced by plasma arc vitrification of a mixed waste surrogate

    SciTech Connect

    Bauman, L.E.; Monts, D.L.; Wang, W. [Mississippi State Univ., Mississippi State, MS (United States). Diagnostic Instrumentation and Analysis Lab.] [and others

    1995-12-31

    Emission spectroscopy has been used to characterize the time histories of volatile species produced by the plasma hearth vitrification of a Savannah River mixed waste surrogate. Relationships have been sought between emission intensity (and hence concentration) of gas-phase species present and operational parameters (melt surface temperature, torch current, torch height). Boiling of the molten glass in the vicinity of the plasma arc attachment area appears to contribute significantly to the volatilization of species in this test. This suggests that operational procedures that minimize boiling can reduce the concentration of toxic species emitted to the off gas system and hence to the environment. These results demonstrate the utility of emission spectroscopy as a monitor of volatile species and provide the foundation for future work to verify and extend the results of this investigation.

  6. Investigation of nanoparticle formation in a plasma produced by femtosecond laser ablation of gold

    SciTech Connect

    Spiga, P.; Hermann, J.; Itina, T.; Grojo, D. [LP3, UMR 6182 CNRS-Faculte des Sciences de Luminy, Case 917, F-13288 Marseille (France); Neamtu, D. [NILPRP- Laser Department, P.O. Box MG-36, R-76900 Bucharest (Romania); Pailharey, D.; Marine, W. [CRMCN, UPR CNRS 7251-Faculte des Sciences de Luminy, Case 901, F-13288 Marseille (France)

    2005-10-31

    The formation of nanoparticles in a plasma produced by the interaction of ultrashort laser pulses with gold has been investigated. Three different experimental techniques were employed. (i) The plume expansion was characterized using fast imaging with the aid of an intensified charge-coupled device. (ii) The plasma composition was analyzed using time- and space-resolved optical emission spectroscopy. (iii) The ablated material was deposited on mica substrates and analyzed by means of atomic force microscopy. As a result, the size-distribution and the overall number of nanoparticles were determined as a function of the laser energy density incident on the target surface. The detection of particles with sizes in the nanometer range supports theoretical modeling according to which phase explosion is the dominant mechanism of metal ablation by ultrashort laser pulses.

  7. Study of nanosecond laser-produced plasmas in atmosphere by spatially resolved optical emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Wei, Wenfu; Wu, Jian; Li, Xingwen; Jia, Shenli; Qiu, Aici

    2013-09-01

    We investigate the evolution of the species from both the target and the air, and the plasma parameter distribution of the nanosecond laser-produced plasmas in atmospheric air. The technique used is spatially resolved optical emission spectroscopy. It is argued that the N II from the air, which is distributed over a wider region than the target species in the early stages of the discharge, is primarily formed by the shock wave. The ionized species have a larger expansion velocity than the excited atoms in the first 100 ns, providing direct evidence for space-charge effects. The electron density decreases with the distance from the target surface in the early stages of the discharge, and both the electron density and the excited temperature variation in the axial direction are found to become insignificant at later stages.

  8. In-package nonthermal plasma degradation of pesticides on fresh produce.

    PubMed

    Misra, N N; Pankaj, S K; Walsh, Tony; O'Regan, Finbarr; Bourke, Paula; Cullen, P J

    2014-04-30

    In-package nonthermal plasma (NTP) technology is a novel technology for the decontamination of foods and biological materials. This study presents the first report on the potential of the technology for the degradation of pesticide residues on fresh produce. A cocktail of pesticides, namely azoxystrobin, cyprodinil, fludioxonil and pyriproxyfen was tested on strawberries. The concentrations of these pesticides were monitored in priori and post-plasma treatment using GC-MS/MS. An applied voltage and time dependent degradation of the pesticides was observed for treatment voltages of 60, 70 and 80 kV and treatment durations ranging from 1 to 5 min, followed by 24h in-pack storage. The electrical characterisation revealed the operation of the discharge in a stable filamentary regime. The discharge was found to generate reactive oxygen and excited nitrogen species as observed by optical emission spectroscopy. PMID:24598029

  9. X-ray generation for medical applications from a laser-produced plasma

    NASA Astrophysics Data System (ADS)

    Grtz, Matthias; Tillman, Carl; Mercer, Ian; Svanberg, Sune

    1996-04-01

    We present investigations on the generation of X-ray radiation suitable for different types of medical imaging. Pulses from a 10 Hz terawatt laser system with a duration of 150 fs are focused onto a solid high-Z material target, with focal spot intensities reaching 10 18 W/cm 2. The produced plasma emits broadband X-ray radiation with photon energies up to the MeV region. The application of this X-ray radiation offers new features for medical radiography. Our source allows magnification imaging as well as ultrashort single-shot exposures. New contrast imaging techniques making use of an enhanced characteristic line emission are investigated. The experimental set-up also allows the study of ablation phenomena from sub-picosecond laser pulses by means of particle deposition on thin glass plates. Deposition patterns were studied dependent on different plasma-generation parameters.

  10. Fundamentals of Discharge Initiation in Pulsed Plasma Thrusters: Threshold Criteria for Undervoltage Breakdown

    Microsoft Academic Search

    James E. Cooley; Edgar Y. Choueiri

    2007-01-01

    In an eort to understand the basic mechanism behind discharge initiation in gas-fed pulsed plasma thsuters, the conditions under which an externally supplied pulse of electrons will induce breakdown in an undervoltaged, low-gain discharge gap are experimentally and theoretically explored. The minimum number of injected electrons required to achieve breakdown in a parallel-plate gap is measured in argon at pd

  11. Laser-produced molybdenum plasma analysis with a Collisional-Radiative model included in the hydrodynamic code med103

    NASA Astrophysics Data System (ADS)

    Wang, Shou-Jun; Dong, Quan-Li; Zhang, Lei; Zhang, Jie

    2010-08-01

    The Collisinal-Radiative (CR) model with fine atomic data included in the hydrodynamic code MED103 is used for the soft x-ray spectra analysis of laser-produced molybdenum plasmas. The charge distribution drawn from the soft x-ray spectra can be used to determine the pre-plasma conditions for the plasma-based molybdenum soft x-ray lasers (SXRLs).

  12. Atmospheric cold plasma inactivation of Escherichia coli, Salmonella enterica serovar Typhimurium and Listeria monocytogenes inoculated on fresh produce.

    PubMed

    Ziuzina, D; Patil, S; Cullen, P J; Keener, K M; Bourke, P

    2014-09-01

    Atmospheric cold plasma (ACP) represents a potential alternative to traditional methods for non-thermal decontamination of foods. In this study, the antimicrobial efficacy of a novel dielectric barrier discharge ACP device against Escherichia coli, Salmonella enterica Typhimurium and Listeria monocytogenes inoculated on cherry tomatoes and strawberries, was examined. Bacteria were spot inoculated on the produce surface, air dried and sealed inside a rigid polypropylene container. Samples were indirectly exposed (i.e. placed outside plasma discharge) to a high voltage (70kVRMS) air ACP and subsequently stored at room temperature for 24h. ACP treatment for 10, 60 and 120s resulted in reduction of Salmonella, E.coli and L.monocytogenes populations on tomato to undetectable levels from initial populations of 3.1, 6.3, and 6.7 log10 CFU/sample, respectively. However, an extended ACP treatment time was necessary to reduce bacterial populations attached on the more complex surface of strawberries. Treatment time for 300s resulted in reduction of E.coli, Salmonella and L.monocytogenes populations by 3.5, 3.8 and 4.2 log10 CFU/sample, respectively, and also effectively reduced the background microflora of tomatoes. PMID:24929725

  13. SiC/C nanocable structure produced in silicon carbide by arc plasma heating

    NASA Astrophysics Data System (ADS)

    Nayak, B. B.

    2012-01-01

    Defect-free and long SiC/C nanocables have been produced by heating SiC powder at 3000C by employing dc arc plasma (Ar) in a specially designed configuration of graphite arc. Microstructural characterizations of the heat-treated powder carried out by TEM, HRTEM, SAED, EDS, and micro Raman spectroscopy showed the nanocables to consist of a SiC shell/sheath stuffed with wire type solid C core. A possible mechanism is discussed to explain the cable-type growth.

  14. Measurements of radial heat wave propagation in laser-produced exploding-foil plasmas

    Microsoft Academic Search

    D. S. Montgomery; O. L. Landen; R. P. Drake; K. G. Estabrook; H. A. Baldis; S. H. Batha; K. S. Bradley; R. J. Procassini

    1994-01-01

    Time-resolved, 2D images of x-ray emission from thin, laser-irradiated titanium foils are presented. The foils are irradiated with 0.35 [mu]m light at intensities of 1[times]10[sup 15] W\\/cm[sup 2] which produces a plasma with electron densities [le]10[sup 22] cm[sup [minus]3] and electron temperature of 3--4 keV. X-ray emission that is characteristic of the thermal heat front is observed to propagate radially

  15. Rapidly Solidified Thick Nickel Base Alloy Deposit with Carbide Particles Produced by Plasma Spraying

    Microsoft Academic Search

    Yasuhiro Hoshiyama; Kentaro Hirano; Kenji Murakami; Hidekazu Miyake

    2007-01-01

    Ni-1.5wt.% C, Ni-1.5wt.%C-14wt.%Cr, and Ni-1.5wt.%C-29wt.%Cr alloy powders were low-pressure plasma sprayed to produce\\u000a nickel-base composite deposits with dispersed carbide particles. The constituent of the as-sprayed deposit formed on a water-cooled\\u000a substrate from the Ni-1.5wt.%C alloy powder is a nickel phase that is supersaturated with carbon. The deposit heat-treated\\u000a at 673K in vacuum consists of a nickel phase, nickel carbide, and

  16. Numerical Simulation of the Thomson Scattering Experiment Performed with 0.351mum Laser-Produced Aluminum Plasmas

    Microsoft Academic Search

    Bin Zhao; Hong Li; Zhebin Wang; Bo Bai; Changxuan Yu; Jian Zheng; Xiaohua Jiang; Wenhong Li; Xiaodong Yuan; Zhijian Zheng

    2006-01-01

    The evolutions of the electron temperatures of aluminum plasmas produced with 0.351 mum laser are simulated by means of one-dimensional hydrodynamic code. The simulations show that the plasma geometry has strong influence on the electron temperature's evolution while the effect of the flux limiter is not so significant. The simulations are in good agreement with the experiments only at some

  17. Spectroscopic diagnostics of ionization balance and electron density in 20 picosecond laser-produced aluminum and magnesium plasmas

    SciTech Connect

    Osterheld, A.L.; Shepherd, R.L.; Eder, D.; Walling, R.S.; Keane, C.; Matthews, D.; Young, B.K.F.; Goldstein, W.H.; Stewart, R.E.; Charatis, G.

    1991-01-01

    A quasi-steady state, collisional-radiative model is used to analyze spectra from aluminum and magnesium plasmas produced by irradiation with 20 picosecond pulses of 0.53{mu} laser light. The model infers the ionization balance and electron density of a plasma from the relative intensities of H-like and He-like x-ray transitions.

  18. The study of time dependent, broadband X-ray emission from ultra-short pulse laser produced plasmas

    SciTech Connect

    Shepherd, R.; Booth, R.; Price, D.; Walling, R.; More, R.; Guethlein, G.; Young, B.; Dunn, J.; Osterheld, A.; Goldstein, W.; Stewart, R. (Lawrence Livermore National Laboratory, P.O. 808, Livermore, California 94550 (United States))

    1994-10-05

    The dynamics of X-ray spectra emitted by an ultrashort laser produced plasma is studied using a 100 fs 800 nm pulses. The broadband emission is used to estimate the time dependent plasma temperature. Experimental results are in a good agreement with hydrodynamic calculations. (AIP) [copyright] 1994 [ital American] [ital Institute] [ital of] [ital Physics

  19. X-ray imaging of laser produced plasmas by a compound 3D x-ray lens

    NASA Astrophysics Data System (ADS)

    Garanin, R. V.; Pavlov, G. A.; Suslov, N. A.; Treushnikov, V. M.; Treushnikov, V. V.; Zhidkov, N. V.

    2015-04-01

    Pilot scheme for the study of plasma under extreme condition is implemented using a compound 3D X-ray lens. Hard X-ray image of laser plasma produced by irradiating of copper foil by intense laser pulse was recorded using this lens.

  20. Note: Characterization of the plasma parameters of a capillary discharge-produced plasma channel waveguide to guide an intense laser pulse

    SciTech Connect

    Higashiguchi, Takeshi; Yugami, Noboru [Department of Advanced Interdisciplinary Sciences and Center for Optical Research and Education (CORE), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Hikida, Masafumi; Terauchi, Hiromitsu; Bai Jinxiang [Department of Advanced Interdisciplinary Sciences and Center for Optical Research and Education (CORE), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Kikuchi, Takashi [Department of Electrical Engineering, Nagaoka University of Technology, Kami-tomiokamachi 1603-1, Nagaoka, Niigata 940-2188 (Japan); Tao Yezheng [Center for Energy Research, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0438 (United States)

    2010-04-15

    We demonstrated the production of an optical waveguide in a capillary discharge-produced plasma using a cylindrical capillary. Plasma parameters of its waveguide were characterized by use of both a Nomarski laser interferometer and a hydrogen plasma line spectrum. A space-averaged maximum temperature of 3.3 eV with electron densities of the order of 10{sup 17} cm{sup -3} was observed at a discharge time of 150 ns and a maximum discharge current of 400 A. An ultrashort, intense laser pulse was guided by use of this plasma channel.

  1. Excimer laser produced plasmas in copper wire targets and water droplets

    NASA Technical Reports Server (NTRS)

    Song, Kyo-Dong; Alexander, D. R.

    1994-01-01

    Elastically scattered incident radiation (ESIR) from a copper wire target illuminated by a KrF laser pulse at lambda = 248 nm shows a dinstinct two-peak structure which is dependent on the incident energy. The time required to reach the critical electron density (n(sub c) approximately = 1.8 x 10(exp 22) electrons/cu cm) is estimated at 11 ns based on experimental results. Detailed ESIR characteristics for water have been reported previously by the authors. Initiation of the broadband emission for copper plasma begins at 6.5 +/- 1.45 ns after the arrival of the laser pulse. However, the broadband emission occurs at 11 +/- 0.36 ns for water. For a diatomic substance such as water, the electron energy rapidly dissipates due to dissociation of water molecules, which is absent in a monatomic species such as copper. When the energy falls below the excitation energy of the lowest electron state for water, it becomes a subexcitation electron. Lifetimes of the subexcited electrons to the vibrational states are estimated to be of the order of 10(exp -9) s. In addition, the ionization potential of copper (440-530 nm) is approximately 6 eV, which is about two times smaller than the 13 eV ionization potential reported for water. The higher ionization potential contributes to the longer observed delay time for plasma formation in water. After initiation, a longer time is required for copper plasma to reach its peak value. This time delay in reaching the maximum intensity is attributed to the energy loss during the interband transition in copper.

  2. Investigation of the optical characteristics of a laser-produced plasma cloud expanding into a background gas

    SciTech Connect

    Annenkov, A I; Bessarab, A V; Galakhov, I V; Garanin, Sergey G; Gusakov, A V; Zhidkov, N V; Zhmailo, V A; Izgorodin, V M; Kovalenko, V P; Krotov, V A; Mis'ko, V V; Novikova, E A; Starodubtsev, V A; Starodubtsev, K V; Statsenko, V P; Sungatullin, R R; Tachaev, G V; Sheremet'ev, Yu N [Russian Federal Nuclear Center 'All-Russian Research Institute of Experimental Physics', Sarov, Nizhnii Novgorod region (Russian Federation)

    2010-12-09

    An investigation is made of the dynamics and visible-range luminosity of the plasma cloud produced behind the front of a shock wave in air at a pressure of 1 Torr. The shock wave was produced on introducing the radiation of the twelve-channel Iskra-5 laser facility with a total energy of {approx}2300 J into a hollow spherical plastic target of mass {approx}10{sup -4} g. Experimental data are compared with simulations. (laser plasma)

  3. Brilliance improvement of laser-produced soft x-ray plasma by a barrel shock

    NASA Astrophysics Data System (ADS)

    Mey, Tobias; Rein, Martin; Gromann, Peter; Mann, Klaus

    2012-07-01

    A method is presented for improving the brilliance of laser-produced soft x-ray sources that are based on pulsed gas jets as the targets. The conversion efficiency of laser energy into soft x-ray radiation is enhanced by locally increasing the particle density of the target species. This is achieved by applying a small background pressure to the supersonic flow emanating from a nozzle. In this manner, a supersonic jet with a so-called barrel shock system is formed. On passing the shocks, particles become locally concentrated, forming high-density regions that are used as the targets. An estimate of possible increases in particle densities is provided. The jet flow is then analyzed experimentally by Schlieren imaging, thus visualizing the spatial shock structure. Additionally, a quantitative measurement of the gas density is made using a Hartmann-Shack wavefront sensor. The beneficial effect of the applied background gas on plasma generation is clearly more prominent than its absorbing effect on the photons originating from the plasma. This is shown for a nitrogen target with helium as the background gas. A plasma, generated behind the barrel shock in the nitrogen jet, emits monochromatic photons at a wavelength of 2.88 nm. The peak brilliance of the source is increased by an order of magnitude, resulting in 3.15 1016 photons (mm2 mrad2 s)-1.

  4. Ion flux enhancements and oscillations in spatially confined laser produced aluminum plasmas

    NASA Astrophysics Data System (ADS)

    Singh, S. C.; Fallon, C.; Hayden, P.; Mujawar, M.; Yeates, P.; Costello, J. T.

    2014-09-01

    Ion signals from laser produced plasmas (LPPs) generated inside aluminum rectangular cavities at a fixed depth d = 2 mm and varying width, x = 1.0, 1.6, and 2.75 mm were obtained by spatially varying the position of a negatively biased Langmuir probe. Damped oscillatory features superimposed on Maxwellian distributed ion signals were observed. Depending on the distance of the probe from the target surface, three to twelve fold enhancements in peak ion density were observed via confinement of the LPP, generated within rectangular cavities of varying width which constrained the plasma plume to near one dimensional expansion in the vertical plane. The effects of lateral spatial confinement on the expansion velocity of the LPP plume front, the temperature, density and expansion velocity of ions, enhancement of ion flux, and ion energy distribution were recorded. The periodic behavior of ion signals was analyzed and found to be related to the electron plasma frequency and electron-ion collision frequency. The effects of confinement and enhancement of various ion parameters and expansion velocities of the LPP ion plume are explained on the basis of shock wave theory.

  5. Initial reaction of hafnium oxide deposited by remote plasma atomic layer deposition method

    SciTech Connect

    Won, Youngdo; Park, Sangwook; Koo, Jaehyoung; Kim, Seokhoon; Kim, Jinwoo; Jeon, Hyeongtag [Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of); Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2005-12-26

    A remote plasma atomic layer deposition (RPALD) method has been applied to grow a hafnium oxide thin film on the Si substrate. The deposition process was monitored by in situ XPS and the as-deposited structure and chemical bonding were examined by TEM and XPS. The in situ XPS measurement showed the presence of a hafnium silicate phase at the initial stage of the RPALD process up to the 20th cycle and indicated that no hafnium silicide was formed. The initial hafnium silicate was amorphous and grew to a thickness of approximately 2 nm. Based on these results and model reactions for silicate formation, we proposed an initial growth mechanism that includes adatom migration at nascent step edges. Density functional theory calculations on model compounds indicate that the hafnium silicate is thermodynamically favored over the hafnium silicide by as much as 250 kJ/mol.

  6. Identification of hydrogenlike and heliumlike transitions in the spectrum of laser-produced magnesium plasmas

    NASA Technical Reports Server (NTRS)

    Moreno, J. C.; Goldsmith, S.; Griem, H. R.; Cohen, Leonard; Knauer, J.

    1990-01-01

    Nonresonance spectral lines of Mg XII and Mg XI emitted by magnesium laser-produced plasmas have been observed in the extreme-vacuum-ultraviolet region and their transitions classified. As many as eight beams of the Omega laser system of the Laboratory for Laser Energetics at the University of Rochester were linearly focused onto magnesium-coated flat targets to produce linear plasma radiation sources from 3 to 6 mm long. The spectra were photographed end-on with a grazing-incidence spectrograph. The identified Mg XII lines are classified as 2s-3p, 2p-3d, 2s-4p, 2p-4d, and 3d-4f transitions. The identified Mg XI lines are classified as 1s2s-1s3p, 1s2p-1s3d, 1s2p-1s4d, 1s3p-1s4d, and 1s3d-1s4f.

  7. Diamond-like carbon produced by plasma source ion implantation as a corrosion barrier

    SciTech Connect

    Lillard, R.S.; Butt, D.P.; Taylor, T.N.; Walter, K.C.; Nastasi, M.

    1998-03-01

    There currently exists a broad range of applications for which the ability to produce an adherent, hard, wear and, corrosion-resistant coating plays a vital role. These applications include engine components, orthopedic devices, textile manufacturing components, hard disk media, optical coatings, and cutting and machining tools (e.g., punches, taps, scoring dies, and extrusion dies). Ion beam processing can play an important role in all of these technologies. Plasma source ion implantation (PSII) is an emerging technology which has the potential to overcome the limitations of conventional ion implantation by: (1) reducing the time and expense for implanting onto complex shapes and large areas and (2) extending the thickness of the modification zone through ion beam enhanced plasma growth of surface coatings. In PSII, targets are placed directly in a plasma source and then pulse biased to produce a non-line-of-sight process for complex-shaped targets without complex fixturing. If the pulse bias is a relatively high negative potential (20 to 100 kV) ion implantation will result. If however, a low voltage (50--1,200 eV) high duty cycle pulse bias is applied, film deposition from the chamber gas will result, thereby increasing the extent of the surface modification into the 1--10 micron regime. To evaluate the potential for DLC to be used as a corrosion barrier, Electrochemical Impedance Spectroscopy (EIS) and traditional electrochemistry techniques were used to investigate the breakdown mechanism in chloride and nonchloride containing environments. The effect of surface preparation on coating breakdown was also evaluated.

  8. Time of flight emission spectroscopy of laser produced nickel plasma: Short-pulse and ultrafast excitations

    SciTech Connect

    Smijesh, N.; Chandrasekharan, K. [Laser and Nonlinear Optics Laboratory, Department of Physics, National Institute of Technology Calicut, Calicut 673601 (India); Joshi, Jagdish C.; Philip, Reji, E-mail: reji@rri.res.in [Ultrafast and Nonlinear Optics Lab, Light and Matter Physics Group, Raman Research Institute, Bangalore 560080 (India)

    2014-07-07

    We report the experimental investigation and comparison of the temporal features of short-pulse (7 ns) and ultrafast (100 fs) laser produced plasmas generated from a solid nickel target, expanding into a nitrogen background. When the ambient pressure is varied in a large range of 10??Torr to 10Torr, the plume intensity is found to increase rapidly as the pressure crosses 1 Torr. Time of flight (TOF) spectroscopy of emission from neutral nickel (Ni I) at 361.9 nm (3d?(D) 4p ? 3d?(D) 4s transition) reveals two peaks (fast and slow species) in short-pulse excitation and a single peak in ultrafast excitation. The fast and slow peaks represent recombined neutrals and un-ionized neutrals, respectively. TOF emission from singly ionized nickel (Ni II) studied using the 428.5 nm (3p?3d?(P) 4s? 3p?3d? 4s) transition shows only a single peak for either excitation. Velocities of the neutral and ionic species are determined from TOF measurements carried out at different positions (i.e., at distances of 2 mm and 4 mm, respectively, from the target surface) on the plume axis. Measured velocities indicate acceleration of neutrals and ions, which is caused by the Coulomb pull of the electrons enveloping the plume front in the case of ultrafast excitation. Both Coulomb pull and laser-plasma interaction contribute to the acceleration in the case of short-pulse excitation. These investigations provide new information on the pressure dependent temporal behavior of nickel plasmas produced by short-pulse and ultrafast laser pulses, which have potential uses in applications such as pulsed laser deposition and laser-induced nanoparticle generation.

  9. Specific aquaporins facilitate Nox-produced hydrogen peroxide transport through plasma membrane in leukaemia cells.

    PubMed

    Vieceli Dalla Sega, Francesco; Zambonin, Laura; Fiorentini, Diana; Rizzo, Benedetta; Caliceti, Cristiana; Landi, Laura; Hrelia, Silvana; Prata, Cecilia

    2014-04-01

    In the last decade, the generation and the role of reactive oxygen species (ROS), particularly hydrogen peroxide, in cell signalling transduction pathways have been intensively studied, and it is now clear that an increase of ROS level affects cellular growth and proliferation pathways related to cancer development. Hydrogen peroxide (H2O2) has been long thought to permeate biological membranes by simple diffusion since recent evidence challenged this notion disclosing the role of aquaporin water channels (AQP) in mediating H2O2 transport across plasma membranes. We previously demonstrated that NAD(P)H oxidase (Nox)-generated ROS sustain glucose uptake and cellular proliferation in leukaemia cells. The aim of this study was to assess whether specific AQP isoforms can channel Nox-produced H2O2 across the plasma membrane of leukaemia cells affecting downstream pathways linked to cell proliferation. In this work, we demonstrate that AQP inhibition caused a decrease in intracellular ROS accumulation in leukaemia cells both when H2O2 was produced by Nox enzymes and when it was exogenously added. Furthermore, AQP8 overexpression or silencing resulted to modulate VEGF capacity of triggering an H2O2 intracellular level increase or decrease, respectively. Finally, we report that AQP8 is capable of increasing H2O2-induced phosphorylation of both PI3K and p38 MAPK and that AQP8 expression affected positively cell proliferation. Taken together, the results here reported indicate that AQP8 is able to modulate H2O2 transport through the plasma membrane affecting redox signalling linked to leukaemia cell proliferation. PMID:24440277

  10. High-order harmonic generation during propagation of femtosecond pulses through the laser-produced plasmas of semiconductors

    NASA Astrophysics Data System (ADS)

    Ganeev, R. A.; Suzuki, M.; Yoneya, S.; Kuroda, H.

    2015-01-01

    The generation of high-order harmonics of the ultrashort pulses of Ti:sapphire laser in the plasma plumes produced during laser ablation of various semiconductors (Te, Se, Si, As, Sb, and Ge) is reported. Application of two-color pump allowed the generation of enhanced odd and even harmonics. The resonance-induced enhancement of single harmonics was observed in the Ge, Se, Sb, As, and Te plasmas. The enhanced 35th harmonic obtained from selenium plasma was twelve times stronger than the neighboring harmonics. We also demonstrate the quasi-phase-matching of the harmonics generated in the As plasma.

  11. Initiation of atomic layer deposition of metal oxides on polymer substrates by water plasma pretreatment

    SciTech Connect

    Steven Brandt, E.; Grace, Jeremy M. [Eastman Kodak Company, 1999 Lake Avenue, Rochester, New York 14650-2022 (United States)

    2012-01-15

    The role of surface hydroxyl content in atomic layer deposition (ALD) of aluminum oxide (AO) on polymers is demonstrated by performing an atomic layer deposition of AO onto a variety of polymer types, before and after pretreatment in a plasma struck in water vapor. The treatment and deposition reactions are performed in situ in a high vacuum chamber that is interfaced to an x-ray photoelectron spectrometer to prevent adventitious exposure to atmospheric contaminants. X-ray photoelectron spectroscopy is used to follow the surface chemistries of the polymers, including theformation of surface hydroxyls and subsequent growth of AO by ALD. Using dimethyl aluminum isopropoxide and water as reactants, ALD is obtained for water-plasma-treated poly(styrene) (PS), poly(propylene) (PP), poly(vinyl alcohol) (PVA), and poly(ethylene naphthalate) (PEN). For PS, PP, and PEN, initial growth rates of AO on the native (untreated) polymers are at least an order of magnitude lower than on the same polymer surface following the plasma treatment. By contrast, native PVA is shown to initiate ALD of AO as a result of the presence of intrinsic surface hydroxyls that are derived from the repeat unit of this polymer.

  12. Flux-dependent Chemical Erosion of Graphite in Deuterium Plasmas: Initial Results from PISCES-B

    NASA Astrophysics Data System (ADS)

    Tynan, George; Brooks, Jeff; Doerner, Russell; Luckhardt, Stan; Seraydarian, Ray

    1998-11-01

    The erosion of carbon from graphite surfaces in hydrogenic plasmas leads to the re-deposition of hydrogenated carbon layers, reduces plasma-facing component lifetime, and is a primary source of carbon impurities in the core plasma of fusion devices. In tritium-containing fusion experiments the redeposited layers can contain high concentrations of tritium and thus directly impact the total tritium inventory of the device. Thus recent evidence (H. Grote et al. 1998 PSI Conference, to be published) of a reduction in the chemical sputtering yield of graphite by hydrogenic plasmas at an elevated ion flux is of interest. Experiments are underway in the PISCES-B http://pisces.ucsd.edu facility to examine this possibility. Initial experiments have been carried out for ion fluxes ranging from 10^21 up to 6x10^22 ions/m^2/sec for incident ion energies of 20-30 eV. Preliminary results suggest a reduction in net sputter yield at the highest fluxes. Spectroscopic measurements and modeling are currently being used to evaluate the significance of redeposition in these experiments. In addition, recent measurements of the abundance of molecular hydrogen ions (J. Zhang, this conference) in similar discharges suggest significant variations in H_2^+ and H_3^+ molecular ion densities for the largest ion fluxes. The significance of these effects on net sputtering will be discussed along with plans for future work.

  13. Plans for Conditioning Plasma-Facing Components at Initiation of NSTX-U Operations

    NASA Astrophysics Data System (ADS)

    Kaita, R.; Blanchard, W.; Cai, D.; Gerhardt, S.; Jaworski, M. A.; Lucia, M.; Rossi, S.; Skinner, C. H.; Allain, J.-P.; Bedoya, F.

    2014-10-01

    The conditioning of plasma-facing components (PFCs) has been critical to the achievement of high performance plasmas in fusion devices. The NSTX-U PFCs will initially consist of graphite. Well-established PFC conditioning will be applied, including high temperature bakeout and glow discharge cleaning (GDC). As in NSTX, the center stack (CS) will be electrically-isolated from the outer vacuum vessel in NSTX-U for coaxial helicity injection (CHI), and this also permits high currents to pass through the CS for baking. Other conditioning techniques are required to further reduce the dominant impurities, which are expected to be carbon and oxygen. Boronization will first be performed, where helium glow discharge cleaning (GDC) is followed by GDC with a mixture of 95% helium and 5% deuterated trimethyl boron (TMB), and another period of helium GDC. This is to be compared with lithiumization, where lithium vapor is evaporated directly on PFC surfaces. The effectiveness of both conditioning techniques has been inferred from plasma measurements subsequent to their application, but the link between them and actual PFC conditions has not been made. The new Materials Analysis and Particle Probe (MAPP) is intended to do this with in situ analysis of PFC samples exposed to NSTX-U plasmas. Work supported by DOE Contract No. DE-AC02-09CH11466 and DE-SC0010717.

  14. Initial confinement studies of ohmically heated plasmas in the Tokamak Fusion Test Reactor

    SciTech Connect

    Efthimion, P.C.; Bell, M.; Blanchard, W.R.; Bretz, N.; Cecchi, J.L.; Coonrod, J.; Davis, S.; Dylla, H.F.; Fonck, R.; Furth, H.P.

    1984-06-01

    Initial operation of the Tokamak Fusion Test Reactor (TFTR) has concentrated upon confinement studies of ohmically heated hydrogen and deuterium plasmas. Total energy confinement times (tau/sub E/) are 0.1 to 0.2 s for a line-average density range (anti n/sub e/) of 1 to 2.5 x 10/sup 19/ m/sup -3/ with electron temperatures of T/sub e/(o) approx. 1.2 to 2.2 keV, ion temperatures of T/sub i/(o) approx. 0.9 to 1.5 keV, and Z/sub eff/ approx. 3. A comparison of PLT, PDX, and TFTR plasma confinement supports a dimension-cubed scaling law.

  15. Report Initial Work on Developing Plasma Modeling Capability in WARP for NDCX Experiments

    SciTech Connect

    Friedman, A; Cohen, R H; Grote, D P; Vay, J

    2007-12-14

    This milestone has been accomplished. The Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) has developed and implemented an initial beam-in-plasma implicit modeling capability in Warp; has carried out tests validating the behavior of the models employed; has compared the results of electrostatic and electromagnetic models when applied to beam expansion in an NDCX-I relevant regime; has compared Warp and LSP results on a problem relevant to NDCX-I; has modeled wave excitation by a rigid beam propagating through plasma; and has implemented and begun testing a more advanced implicit method that correctly captures electron drift motion even when timesteps too large to resolve the electron gyro-period are employed. The HIFS-VNL is well on its way toward having a state-of-the-art source-to-target simulation capability that will enable more effective support of ongoing experiments in the NDCX series and allow more confident planning for future ones.

  16. Excitation wavelength dependence of water-window line emissions from boron-nitride laser-produced plasmas

    E-print Network

    Harilal, S. S.

    . Plasmas are produced by focusing 1064 nm and harmonically generated 532 and 266 nm radiation from a Nd as laser wavelength is shortened. Filtered photodiode measurements of angular dependence showed that 266 and 532 nm laser wavelengths produce uniform emission. VC 2012 American Institute of Physics. [doi:10

  17. The Ulysses solar wind plasma investigation: Description and initial in-ecliptic results

    SciTech Connect

    Bame, S.J.; Phillips, J.L.; McComas, D.J.; Gosling, J.T. (Los Alamos National Lab., NM (United States)); Goldstein, B.E. (Jet Propulsion Lab., Pasadena, CA (United States))

    1991-01-01

    During the in-ecliptic flight of Ulysses from the Earth toward its encounter with Jupiter, the Los Alamos solar wind plasma experiment has performed well. Briefly described, the instrumentation contains two independent electrostatic analyzers, one for ions and one for electrons. Initial analysis of solar wind electron core temperatures obtained between 1.15 and 3.76 AU yields a gradient of T {proportional to} R{sup {minus}0.7} which is flatter than expected for adiabatic expansion of a single-temperature Maxwellian velocity distribution and steeper than that obtained from Mariner-Voyager.

  18. Nanocluster Formation within the Vapor Plume, Produced by Nanosecond-Laser Ablation: Effect of Initial Density and Pressure Distributions

    Microsoft Academic Search

    Masahiro Kuwata; Boris Luk'yanchuk; Takashi Yabe

    2001-01-01

    The condensation of vapor in the expanding plume produced by ns-laser ablation is discussed within the framework of the Zeldovich and Raizer theory of condensation. The spherical plume expansion is described by a numerical solution of the hydrodynamic equations by the cubic interpolated pseudo-particle (CIP) method. This permits us to analyze the role of initial distributions of density and pressure

  19. Nanocluster formation within the vapor plume produced by nanosecond laser ablation: effect of the initial density and pressure distributions

    Microsoft Academic Search

    Y. Kuwata; Boris S. Luk'yanchuk; Takashi Yabe

    2000-01-01

    The condensation of vapor within the expanding plume produced by ns-laser ablation is discussed in the framework of Zeldovich and Raizer theory of condensation. The spherical plume expansion is described by numerical solution of hydrodynamic equations by CIP method. This permits to analyze the role of initial distributions in density and pressure onto the size distribution function for nanoclusters. With

  20. Combinatorial plasma polymerization approach to produce thin films for testing cell proliferation.

    PubMed

    Antonini, V; Torrengo, S; Marocchi, L; Minati, L; Dalla Serra, M; Bao, G; Speranza, G

    2014-01-01

    Plasma enhanced physical vapor depositions are extensively used to fabricate substrates for cell culture applications. One peculiarity of the plasma processes is the possibility to deposit thin films with reproducible chemical and physical properties. In the present work, a combinatorial plasma polymerization process was used to deposit thin carbon based films to promote cell adhesion, in the interest of testing cell proliferation as a function of the substrate chemical properties. Peculiarity of the combinatorial approach is the possibility to produce in just one deposition experiment, a set of surfaces of varying chemical moieties by changing the precursor composition. A full characterization of the chemical, physical and thermodynamic properties was performed for each set of the synthesized surfaces. X-ray photoelectron spectroscopy was used to measure the concentration of carboxyl, hydroxyl and amine functional groups on the substrate surfaces. A perfect linear trend between polar groups' density and precursors' concentration was found. Further analyses reveled that also contact angles and the correspondent surface energies of all deposited thin films are linearly dependent on the precursor concentration. To test the influence of the surface composition on the cell adhesion and proliferation, two cancer cell lines were utilized. The cell viability was assessed after 24 h and 48 h of cell culture. Experiments show that we are able to control the cell adhesion and proliferation by properly changing the thin film deposition conditions i.e. the concentration and the kind of chemical moiety on the substrate surface. The results also highlight that physical and chemical factors of biomaterial surface, including surface hydrophobicity and free energy, chemical composition, and topography, can altered cell attachment. PMID:24121075

  1. Laser produced plasma sources for nanolithography--Recent integrated simulation and benchmarking

    NASA Astrophysics Data System (ADS)

    Hassanein, A.; Sizyuk, T.

    2013-05-01

    Photon sources for extreme ultraviolet lithography (EUVL) are still facing challenging problems to achieve high volume manufacturing in the semiconductor industry. The requirements for high EUV power, longer optical system and components lifetime, and efficient mechanisms for target delivery have narrowed investigators towards the development and optimization of dual-pulse laser sources with high repetition rate of small liquid tin droplets and the use of multi-layer mirror optical system for collecting EUV photons. We comprehensively simulated laser-produced plasma sources in full 3D configuration using 10-50 ?m tin droplet targets as single droplets as well as, for the first time, distributed fragmented microdroplets with equivalent mass. The latter is to examine the effects of droplet fragmentation resulting from the first pulse and prior to the incident second main laser pulse. We studied the dependence of target mass and size, laser parameters, and dual pulse system configuration on EUV radiation output and on atomic and ionic debris generation. Our modeling and simulation included all phases of laser target evolution: from laser/droplet interaction, energy deposition, target vaporization, ionization, plasma hydrodynamic expansion, thermal and radiation energy redistribution, and EUV photons collection as well as detail mapping of photons source size and location. We also simulated and predicted the potential damage to the optical mirror collection system from plasma thermal and energetic debris and the requirements for mitigating systems to reduce debris fluence. The debris effect on mirror collection system is analyzed using our three-dimensional ITMC-DYN Monte Carlo package. Modeling results were benchmarked against our CMUXE laboratory experimental studies for the EUV photons production and for debris and ions generation.

  2. Structure and surface correlations to the optical properties of nonthermal plasma-produced silicon nanoparticles

    NASA Astrophysics Data System (ADS)

    Anthony, Rebecca Joy

    Nanomaterials have diverse capabilities to enable new technology and to deepen our understanding of our world, providing exciting prospects for scientists and the public alike in a vast span of uses. In the past decade, however, the potential held by nanotechnology has been reframed in the context of helping to slow global climate change and to alter the ways in which we use our energy to reflect more efficient technology and renewable energy sources. Silicon is a standout material in this new framework: as a nanomaterial, silicon can emit light when exposed to an applied voltage or ultraviolet optical excitation source. Silicon nanocrystals also exhibit size-dependent light emission, due to quantum confinement. This thesis is an exploration of the synthesis and processing parameters that affect the optical performance of silicon nanocrystals produced in a nonthermal plasma reactor. The efficiency of this light emission is sensitive to both synthesis environment and post-synthesis treatment. The work presented here is an attempt to deepen our understanding of the effects of different reactor and treatment parameters on the light emission efficiency from silicon nanoparticles, such that the luminescence behavior of the nanoparticles can be specifically engineered. Being able to fine-tune the structure, surface, and optical characteristics of the silicon nanocrystals is key in maximizing their use in luminescence applications. For all of the experiments described here, a nonthermal plasma flow-through reactor has been used to create the silicon nanoparticles. Silane gas is dissociated in the plasma and fragments come together to form silicon clusters, then grow to create nanoparticles. The nanoparticles were collected from the reactor for further processing, characterization, and experiments. The first discovery in this project was that by adjusting the power to the plasma reactor, the crystallinity of the silicon particles can be tuned: low power results in amorphous silicon nanoparticles, and high power yields crystalline nanoparticles. Even more important, the crystallinity of a nanoparticle ensemble relates directly to the photoluminescence (PL) efficiency, or quantum yield, from the ensemble: crystalline silicon nanoparticle samples, after alkyl functionalization, exhibit PL efficiencies of 40% or greater, while amorphous samples emit light with very poor efficiency (<2%). Additional studies of the plasma reactor revealed the importance of injecting a flow of hydrogen gas into the afterglow of the plasma, which turns out to have dramatic implications for the ultimate PL quantum yields of the nanocrystals. This injection scheme was systematically studied by varying the injected gas and its position. Hydrogen injected directly into the plasma afterglow was found to be vital for achieving high quantum-yield silicon nanocrystals, likely due to a reduction in surface trap states due to additional hydrogen passivation at the nanocrystal surface. Further investigations into the nanocrystal surface and how it relates to PL quantum yield showed that the photoluminescence from silicon nanocrystals is not only dependent on synthesis parameters, but also on processing temperatures and procedures following synthesis. While the highest PL efficiencies are found for silicon nanocrystals capped with alkyl chains, the PL efficiency of a nanocrystal ensemble can also be improved simply by heating the sample to temperatures between 150-200 C. This heating step also leads to a change in the hydride structure at the nanocrystal surface, which appears to be brought about by the effusion of silyl (or disilane) groups. Finally, details of the construction of a silicon-nanocrystal-based LED will be discussed. The LED project is part of a collaboration, and while the majority of device-specific aspects of the project were carried out in the lab of Professor R. Holmes by his Ph.D. student Kai-Yuan Cheng, the processing and alterations made to the nanocrystals used in the LED were all the responsibility of the author. The details of the pr

  3. Magnetic reconnection in high-energy-density laser-produced plasmas

    SciTech Connect

    Fox, W.; Bhattacharjee, A.; Germaschewski, K. [Center for Integrated Computation and Analysis of Reconnection and Turbulence, and Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, University of New Hampshire, Durham, New Hampshire 03824 (United States)

    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.

  4. Plasma waves produced by an ion beam: Observations by the VLF experiment on Porcupine

    NASA Astrophysics Data System (ADS)

    Jones, D.

    1980-06-01

    Results are presented from the VLF electric field experiments flown on Porcupine flights F3 and F4, which also had ejectable xenon ion sources. The xenon ion beam was found to produce plasma instabilities whose frequencies could be linked to the local proton gyrofrequency. The main energy in the instabilities lies at 3kHz for events when the Xe+ source is close to the rocket, and at 7kHz when the source is farther away. Theory predicts that these frequencies should be the lower-hybrid-resonance and this implies that Xe+ is the dominant ion in the first case and that it is the ambient plasma that dominates later. There is no discernable antenna spin-modulation during the Xe events which indicates that the wave k-vectors are not unidirectional. A theory is cited based on the setting up of the proton cyclotron harmonic waves by the Xe+ or 0+ cyclotron harmonic waves. The second Xe+ event on both flights exhibited an, as yet, unexplained harmonic structure related to half the local proton gyrofrequency.

  5. Kinetics of ion and prompt electron emission from laser-produced plasma

    SciTech Connect

    Farid, N. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States) [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China); Harilal, S. S.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)] [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Ding, H. [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China)] [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China)

    2013-07-15

    We investigated ion emission dynamics of laser-produced plasma from several elements, comprised of metals and non-metals (C, Al, Si, Cu, Mo, Ta, W), under vacuum conditions using a Faraday cup. The estimated ion flux for various targets studied showed a decreasing tendency with increasing atomic mass. For metals, the ion flux is found to be a function of sublimation energy. A comparison of temporal ion profiles of various materials showed only high-Z elements exhibited multiple structures in the ion time of flight profile indicated by the observation of higher peak kinetic energies, which were absent for low-Z element targets. The slower ions were seen regardless of the atomic number of target material propagated with a kinetic energy of 15 keV, while the fast ions observed in high-Z materials possessed significantly higher energies. A systematic study of plasma properties employing fast photography, time, and space resolved optical emission spectroscopy, and electron analysis showed that there existed different mechanisms for generating ions in laser ablation plumes. The origin of high kinetic energy ions is related to prompt electron emission from high-Z targets.

  6. Kinetics of ion and prompt electron emission from laser-produced plasma

    NASA Astrophysics Data System (ADS)

    Farid, N.; Harilal, S. S.; Ding, H.; Hassanein, A.

    2013-07-01

    We investigated ion emission dynamics of laser-produced plasma from several elements, comprised of metals and non-metals (C, Al, Si, Cu, Mo, Ta, W), under vacuum conditions using a Faraday cup. The estimated ion flux for various targets studied showed a decreasing tendency with increasing atomic mass. For metals, the ion flux is found to be a function of sublimation energy. A comparison of temporal ion profiles of various materials showed only high-Z elements exhibited multiple structures in the ion time of flight profile indicated by the observation of higher peak kinetic energies, which were absent for low-Z element targets. The slower ions were seen regardless of the atomic number of target material propagated with a kinetic energy of 1-5 keV, while the fast ions observed in high-Z materials possessed significantly higher energies. A systematic study of plasma properties employing fast photography, time, and space resolved optical emission spectroscopy, and electron analysis showed that there existed different mechanisms for generating ions in laser ablation plumes. The origin of high kinetic energy ions is related to prompt electron emission from high-Z targets.

  7. Thermophysical property measurement at high temperatures by laser-produced plasmas

    SciTech Connect

    Kim, Y.W. [Lehigh Univ., Bethehem, PA (United States)

    1993-05-01

    Excitation by a high-power laser pulse of a material surface generates a sequence of plasma, fluid flow, and acoustic events. These are well separated in time, and their detection and analysis can lead to determination of material properties of the condensed phase target. We have developed a new methodology for real-time determination of molten metal composition by time-resolved spectroscopy of laser-produced plasmas (LPP). If the laser pulse is shaped in such a way that the movement of the bulk surface due to evaporation is kept in pace with the thermal diffusion front advancing into the interior of the target, the LPP plume becomes representative of the bulk in elemental composition. In addition, the mass loss due to LPP ablation is very well correlated with the thermal diffusivity of the target matter. For several elemental solid specimens, we show that the product of the ablation thickness and heat of formation is proportional to the thermal diffusivity per unit molecular weight. Such measurements can be extended to molten metal specimens if the mass loss by ablation, density, heat of formation, and molecular weight can be determined simultaneously. The results from the solid specimen and the progress with a levitation-assisted molten metal experiment are presented.

  8. Simulation of particle velocity in a laser-produced tin plasma extreme ultraviolet source

    SciTech Connect

    Masnavi, Majid; Nakajima, Mitsuo; Horioka, Kazuhiko [Department of Energy Sciences, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Araghy, Homaira Parchamy [Plasma Physics Research Center, Azad University, Tehran (Iran, Islamic Republic of); Endo, Akira [Friedrich-Schiller University, Institute of Applied Physics, Jena (Germany)

    2011-06-15

    In connection with fast heating in a laser produced plasma (LPP) extreme ultraviolet (EUV) source, the superheating behavior of bulk tin (Sn) at high heating rates is investigated. A constant temperature and pressure molecular dynamics simulation using modified Lennard-Jones and Coulomb potentials suitable for studying the liquid structure of Sn is employed in order to derive the caloric curves of the solid and liquid phases. The results have shown transient effects on the phase transitions. Superheating is observed during the melting and vaporizing processes. The velocity distribution of Sn particles against typical laser fluence in a LPP EUV light source has been numerically investigated using a simplified method including a one-dimensional, two-temperature, molecular dynamics, and steady-state ionization model. In the framework of our model, it was found that ejected Sn particles have a maximum velocity on the order of 10 to 40 km/s in plasma created using a nanosecond pre-pulse neodymium-doped yttrium aluminum garnet (Nd:YAG, 1.06 {mu}m) laser in EUV lithography experiments.

  9. Simulation of particle velocity in a laser-produced tin plasma extreme ultraviolet source

    NASA Astrophysics Data System (ADS)

    Masnavi, Majid; Nakajima, Mitsuo; Horioka, Kazuhiko; Araghy, Homaira Parchamy; Endo, Akira

    2011-06-01

    In connection with fast heating in a laser produced plasma (LPP) extreme ultraviolet (EUV) source, the superheating behavior of bulk tin (Sn) at high heating rates is investigated. A constant temperature and pressure molecular dynamics simulation using modified Lennard-Jones and Coulomb potentials suitable for studying the liquid structure of Sn is employed in order to derive the caloric curves of the solid and liquid phases. The results have shown transient effects on the phase transitions. Superheating is observed during the melting and vaporizing processes. The velocity distribution of Sn particles against typical laser fluence in a LPP EUV light source has been numerically investigated using a simplified method including a one-dimensional, two-temperature, molecular dynamics, and steady-state ionization model. In the framework of our model, it was found that ejected Sn particles have a maximum velocity on the order of 10 to 40 km/s in plasma created using a nanosecond pre-pulse neodymium-doped yttrium aluminum garnet (Nd:YAG, 1.06 ?m) laser in EUV lithography experiments.

  10. Probe measurements of the electron distribution function in an electron-beam-produced ytterbium plasma

    SciTech Connect

    Bobrova, A. A.; Dubinov, A. E.; Esin, M. I.; Zolotov, S. V.; Maksimov, A. N.; Selemir, V. D.; Sidorov, I. I.; Shubin, A. Yu. [Russian Federal Nuclear Center, All-Russia Research Institute of Experimental Physics (Russian Federation)

    2011-01-15

    A nonequilibrium anisotropic plasma produced by an electron beam in the residual air with a low content of ytterbium vapor was investigated by the probe method. It is found that a minor (at a level of a few ppm) admixture of ytterbium to low-pressure air substantially modifies the electron energy distribution function (EEDF): the main peak corresponding to thermal electrons broadens, and new peaks appear. It is shown that the observed change in the EEDF is caused by the low ionization energy of ytterbium, due to which one beam electron can ionize several ytterbium atoms. The new peaks in the EEDF correspond to the final energies of a beam electron after each subsequent ionizing collision with ytterbium atoms.

  11. Ultrafine grained high density manganese zinc ferrite produced using polyol process assisted by Spark Plasma Sintering

    NASA Astrophysics Data System (ADS)

    Gaudisson, T.; Beji, Z.; Herbst, F.; Nowak, S.; Ammar, S.; Valenzuela, R.

    2015-08-01

    We report the synthesis of Mn-Zn ferrite (MZFO) nanoparticles (NPs) by the polyol process and their consolidation by Spark Plasma Sintering (SPS) technique at relatively low temperature and short time, namely 500 C for 10 min. NPs were obtained as perfectly epitaxied aggregated nanoclusters forming a kind of spherical pseudo-single-crystals of about 40 nm in size. The results on NPs consolidation by SPS underlined the importance of this clustering on the grain growth mechanism. Grain growth proceeds by coalescing nanocrystalline aggregates into single grain of almost the same average size, thus leading to a high density ceramic. Due to magnetic exchange interactions between grains, the produced ceramic does not exhibit thermal relaxation whereas their precursor polyol-made NPs are superparamagnetic.

  12. Optical and Electrical Properties of Heterogeneous Coatings Produced by Aluminum Powder and Boehmite Suspension Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Brousse-Pereira, E.; Wittmann-Teneze, K.; Bianchi, V.; Longuet, J. L.; Del Campo, L.

    2012-12-01

    Spectral selective materials have attracted an increasing interest because of Concentration Solar Power Plant. Those materials are expected to exhibit specific optical properties at temperatures higher than 450 C. Plasma-spraying process is commonly used to manufacture high-temperature coatings. In this study, heterogeneous coatings made of aluminum and alumina were produced by spraying both powder and suspension of boehmite clusters. Both optical and electrical properties were measured because, according to the Hagen-Ruben's law, the higher the resistivity the lower the reflectivity. The reflectivity was assessed by spectrometry at 10 m and the resistivity by the four-points technique. The results were combined with the diameter of flattened lamellae and the volume fraction of alumina in the coatings. Then the highest reflectivity is achieved with a metallic coating exhibiting high flattening degree, while the coatings containing a large amount of alumina exhibit the lowest reflectivity and the highest resistivity.

  13. Moisture resistant and anti-reflection optical coatings produced by plasma polymerization of organic compounds

    NASA Technical Reports Server (NTRS)

    Hollahan, J. R.; Wydeven, T.

    1975-01-01

    The need for protective coatings on critical optical surfaces, such as halide crystal windows or lenses used in spectroscopy, has long been recognized. It has been demonstrated that thin, one micron, organic coatings produced by polymerization of flourinated monomers in low temperature gas discharge (plasma) exhibit very high degrees of moisture resistence, e.g., hundreds of hours protection for cesium iodide vs. minutes before degradation sets in for untreated surfaces. The index of refraction of these coatings is intermediate between that of the halide substrate and air, a condition for anti-reflection, another desirable property of optical coatings. Thus, the organic coatings not only offer protection, but improved transmittance as well. The polymer coating is non-absorbing over the range 0.4 to 40 microns with an exception at 8.0 microns, the expected absorption for C-F bonds.

  14. High bandwidth data recording systems for pulsed power and laser produced plasma experiments

    SciTech Connect

    May, M. J.; Clancy, T.; Fittinghoff, D.; Halvorson, C.; Mills, T.; Nikitin, A.; Perry, T.; Roberson, G. P.; Smith, D.; Teruya, A.; Miller, E. K.; Trainham, C. [Lawrence Livermore National Laboratory, 7000 East Avenue Livermore, California 94550 (United States); Special Technologies Laboratory, Bechtel Nevada, 5520 Ekwill Street, Suite B, Santa Barbara, California 93111 (United States)

    2006-10-15

    We present two high bandwidth data transmission and recording systems for the measurement of transient signals during pulsed power and laser produced plasmas. These systems use fiber optic cables to transmit analog data over long distances to high bandwidth digitizing oscilloscopes. One system is based on the direct modulation of a laser diode and has a bandwidth of 1.5 GHz. The other system is based upon a Mach-Zehnder modulator and has a bandwidth of 12 GHz, and is limited by the photoreceiver. The signals are recorded on commercial digitizing oscilloscopes that have approximately six effective bits. The transmission systems use many off-the-shelf components from the telecommunications industry and thus have a high reliability and a moderate cost. Investigation of the reduction in optical transmission of the fibers during exposure to high dose radiation will also be discussed.

  15. High Bandwidth Data Recording Systems for Pulsed Power and Laser Produced Plasma Experiments.

    SciTech Connect

    May, M J; Clancy, T; Fittinghoff, D; Halvorson, C; MIlls, T; Nikitin, A; Perry, T; Roberson, P; Smith, D; Teruya, A; Miller, K; Trainham, C

    2006-05-02

    We present two high bandwidth data transmission and recording systems for the measurement of transient signals during pulsed power and laser produced plasmas. These systems use fiber optic cables to transmit analog data over long distances to high bandwidth digitizing oscilloscopes. One system is based on the direct modulation of a laser diode and has a bandwidth of 1.5 GHz. The other system is based upon a fiber-optic Mach-Zehnder modulator and has a bandwidth of 12 GHz, and is limited by the photo receiver. The signals are recorded on commercial digitizing oscilloscopes that have approximately 6 effective bits. The transmission systems use many off-the-shelf components from the telecommunications industry and thus have a high reliability and a moderate cost. Results from recent measurements will be presented. Investigation of the reduction in optical transmission by the fibers during exposure to high dose radiation will also be discussed.

  16. Influence of spot size on propagation dynamics of laser-produced tin plasma

    SciTech Connect

    Harilal, S. S. [Center for Energy Research, University of California San Diego, La Jolla, California 92093 (United States)

    2007-12-15

    The plume dynamics in the presence of an ambient gas is very intriguing physics. The expansion of a laser-produced plasma in the presence of an ambient gas leads to internal plume structures, plume splitting, sharpening, confinement, etc. We investigated propagation dynamics of an expanding tin plume for various spot sizes using a fast visible plume imaging and Faraday cup diagnostic tools. Our results indicate that the sharpening of the plume depends strongly on the spot size. With a smaller spot size, the lateral expansion is found to be higher and the plume expansion is spherical while with a larger spot size the plume expansion is more cylindrical. Analysis of time resolved imaging also showed internal structures inside the plume.

  17. Measurements of radial heat wave propagation in laser-produced exploding-foil plasmas

    SciTech Connect

    Montgomery, D.S.; Landen, O.L.; Drake, R.P.; Estabrook, K.G.; Baldis, H.A.; Batha, S.H.; Bradley, K.S.; Procassini, R.J. (Lawrence Livermore National Laboratory, Livermore, California 94551 (United States) Plasma Physics Research Institute, University of California Davis, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States) Department of Applied Science, University of California Davis, Davis, California 95616 (United States))

    1994-10-10

    Time-resolved, 2D images of x-ray emission from thin, laser-irradiated titanium foils are presented. The foils are irradiated with 0.35 [mu]m light at intensities of 1[times]10[sup 15] W/cm[sup 2] which produces a plasma with electron densities [le]10[sup 22] cm[sup [minus]3] and electron temperature of 3--4 keV. X-ray emission that is characteristic of the thermal heat front is observed to propagate radially outward from the heated region. Comparison of these measurements with 2D hydrodynamic simulations of the experiment suggests the radial heat flux to be about 3% of the free-streaming heat flux.

  18. High average power, highly brilliant laser-produced plasma source for soft X-ray spectroscopy.

    PubMed

    Mantouvalou, Ioanna; Witte, Katharina; Grtzsch, Daniel; Neitzel, Michael; Gnther, Sabrina; Baumann, Jonas; Jung, Robert; Stiel, Holger; Kanngiesser, Birgit; Sandner, Wolfgang

    2015-03-01

    In this work, a novel laser-produced plasma source is presented which delivers pulsed broadband soft X-radiation in the range between 100 and 1200 eV. The source was designed in view of long operating hours, high stability, and cost effectiveness. It relies on a rotating and translating metal target and achieves high stability through an on-line monitoring device using a four quadrant extreme ultraviolet diode in a pinhole camera arrangement. The source can be operated with three different laser pulse durations and various target materials and is equipped with two beamlines for simultaneous experiments. Characterization measurements are presented with special emphasis on the source position and emission stability of the source. As a first application, a near edge X-ray absorption fine structure measurement on a thin polyimide foil shows the potential of the source for soft X-ray spectroscopy. PMID:25832284

  19. Plasma-initiated laser deposition of polycrystalline and monocrystalline silicon films

    SciTech Connect

    Gee, J.M.; Hargis, P.J. Jr.; Carr, M.J.; Tallant, D.R.; Light, R.W.

    1983-01-01

    This paper reports a new method of silicon deposition using the interaction between the radiation from a pulsed ultraviolet excimer laser and the plasma species produced in a glow discharge in silicane (SiH/sub 4/). Examination of the deposited film by laser Raman spectroscopy and by transmission electron microscopy revealed that the morphology ranged from polycrystalline silicon at laser fluences of 0.13 to 0.17 J/cm/sup 2/ to epitaxial silicon at fluences of 0.4 to 0.6 J/cm/sup 2/. Growth rates of 100 nm/min for polycrystalline silicon and 30 nm/min for monocrystalline silicon were achieved.

  20. Rayleigh-Taylor-Induced Electromagnetic Fields in Laser-Produced Plasmas

    NASA Astrophysics Data System (ADS)

    Manuel, Mario J.-E.

    Spontaneous electromagnetic fields can be important to the dynamic evolution of a plasma by directing heat flow as well as providing additional pressures on the conducting fluids through the Lorentz force. Electromagnetic fields are predicted to affect fluid behavior during the core-collapse of supernovae through generation of fields due to hydrodynamic instabilities. In the coronae of stars, self-generated magnetic fields lead to filamentary structure in the hot plasma. Recent experiments by Gregori et al. investigated sources of protogalactic magnetic fields generated by laser-produced shock waves. In inertial confinement fusion experiments, self-generated electromagnetic fields can also play a role and have recently become of great interest to the community. Present day laser facilities provide a unique opportunity to study spontaneous field-generation in these extreme environments under controlled conditions. Instability-induced electromagnetic fields were investigated using a novel monoenergetic-proton radiography system. Fusion protons generated by an 'exploding-pusher' implosion were used to probe laser-irradiated plastic foils with various preimposed surface perturbations. Imaging protons are sensitive to electromagnetic fields and density modulations in the plasma through the Lorentz force and Coulomb collisions, respectively. Corresponding x-ray radiographs of these targets provided mass density distributions and Coulomb effects on protons were assessed using a Monte Carlo code written using the Geant4 framework. Proton fluence distributions were recorded on CR-39 detectors and Fourier analyzed to infer path-integrated field strengths. Rayleigh-Taylor (RT) growth of preimposed surface perturbations generated magnetic fields by the RT-induced Biermann battery and were measured for the first time. Good data were obtained during linear growth and when compared to ideal calculations, demonstrated that field diffusion near the source played an important role. At later times in the plasma evolution, 3-D cellular structures were observed for all foil types. These features were found to be analogous to previously observed filamentary field structures by Seguin et al. in laser-driven spherical targets. Face-on images of these field structures provided good data to quantitatively analyze the size of these features, not previously attainable due to the complexity of the 3-D spherical data. Work presented here demonstrates that these field structures are likely caused by the magnetothermal instability in the underdense corona. (Copies available exclusively from MIT Libraries, libraries.mit.edu/docs - docs mit.edu)

  1. From the regulatory functions of B cells to the identification of cytokine-producing plasma cell subsets.

    PubMed

    Dang, Van Duc; Hilgenberg, Ellen; Ries, Stefanie; Shen, Ping; Fillatreau, Simon

    2014-06-01

    B lymphocytes have a unique role as antibody-producing cells. Antibodies are key mediators of humoral immunity against infections, and are thought to account for the protection afforded by successful vaccines. B cells can also secrete cytokines and subsequently regulate immune responses mediated by T and innate cells. Remarkably, recent studies identified plasma blasts/plasma cells as the main types of activated B cells producing the cytokines interleukin (IL)-10, IL-35, tumor necrosis factor (TNF)-?, IL-17, and GM-CSF in various contexts in mice. Here, we discuss these observations, which suggest the existence of various subsets of plasma blast/plasma cells distinguishable through their cytokine expression pattern. PMID:24637161

  2. Initial Thomson Scattering Survey of Local Helicity Injection and Ohmic Plasmas at the Pegasus Toroidal Experiment

    NASA Astrophysics Data System (ADS)

    Schlossberg, D. J.; Bodner, G. M.; Bongard, M. W.; Fonck, R. J.; Winz, G. R.

    2014-10-01

    A multipoint Thomson scattering diagnostic has recently been installed on the Pegasus ST. The system utilizes a frequency-doubled Nd:YAG laser (?0 ~ 532 nm), spectrometers with volume phase holographic gratings, and a gated, intensified CCD camera. It provides measurements of Te and ne at 8 spatial locations for each spectrometer once per discharge. A new multiple aperture and beam dump system has been implemented to mitigate interference from stray light. This system has provided initial measurements in the core region of plasmas initiated by local helicity injection (LHI), as well as conventional Ohmic L- and H-mode discharges. Multi-shot averages of low-density (ne ~ 3 1018 m-3) , Ip ~ 0 . 1 MA LHI discharges show central Te ~ 75 eV at the end of the helicity injection phase. Ip ~ 0 . 13 MA Ohmic plasmas at moderate densities (ne ~ 2 1019 m-3) have core Te ~ 150 eV in L-mode. Generally, these plasmas do not reach transport equilibrium in the short 25 ms pulse length available. After an L-H transition, strong spectral broadening indicates increasing Te, to values above the range of the present spectrometer system with a high-dispersion VPH grating. Near-term system upgrades will focus on deploying a second spectrometer, with a lower-dispersion grating capable of measuring the 0.1-1.0 keV range. The second spectrometer system will also increase the available number of spatial channels, enabling study of H-mode pedestal structure. Work supported by US DOE Grant DE-FG02-96ER54375.

  3. Absolute soft x-ray calibration of laser produced plasmas using a focusing crystal von Hamos spectrometer

    NASA Astrophysics Data System (ADS)

    Weeks, Tyler; Shevelko, Alexander

    2005-05-01

    Absolute x-ray calibration of laser-produced plasmas was performed using a focusing crystal von Hamos spectrometer. The plasmas were created by a high repetition rate Nd-YAG laser (0.53 ?m/200 mJ/3 ns/10 Hz) on massive solid targets (Mg, Al, Fe, Cu, Mo, Ta). Cylindrical mica crystal (radius of curvature R=20 mm) and a CCD linear array as a detector (Toshiba model TCD 1304AP) were used in the spectrometer. Both the mica crystal and CCD linear array were absolutely calibrated in a spectral range of ?=7-15 . The spectrometer was used for absolute spectral measurements and the determination of the plasma parameters. High spectrometer efficiency allows for the monitoring of absolute x-ray spectra, x-ray yield and plasma parameters in each laser shot. This spectrometer is promising for absolute spectral measurements and for monitoring of laser-plasma sources intended for proximity print lithography.

  4. Prediction of pregnancy viability in bovine in vitro-produced embryos and recipient plasma with Fourier transform infrared spectroscopy

    PubMed Central

    Muoz, M.; Uyar, A.; Correia, E.; Dez, C.; Fernandez-Gonzalez, A.; Caamao, J. N.; Martnez-Bello, D.; Trigal, B.; Humblot, P.; Ponsart, C.; Guyader-Joly, C.; Carrocera, S.; Martin, D.; Marquant Le Guienne, B.; Seli, E.; Gomez, E.

    2014-01-01

    We analyzed embryo culture medium (CM) and recipient blood plasma using Fourier transform infrared (FTIR) metabolomics to predict pregnancy outcome. Individually cultured, in vitro-produced (IVP) blastocysts were transferred to recipients as fresh and vitrified-warmed. Spent CM and plasma samples were evaluated using FTIR. The discrimination capability of the classifiers was assessed for accuracy, sensitivity (pregnancy), specificity (nonpregnancy), and area under the receiver operator characteristic curve (AUC). Within all IVP fresh embryos (birth rate = 52%), high AUC were obtained at birth, especially with expanded blastocysts (CM: 0.80 0.053; plasma: 0.89 0.034). The AUC of vitrified IVP embryos (birth rate = 31%) were 0.607 0.038 (CM, expanded blastocysts) and 0.672 0.023 (plasma, all stages). Recipient plasma generally predicted pregnancy outcome better than did embryo CM. Embryos and recipients with improved pregnancy viability were identified, which could increase the economic benefit to the breeding industry. PMID:24997663

  5. Evidence of filamentation \\/self-focusing\\/ of a laser beam propagating in a laser-produced aluminium plasma

    Microsoft Academic Search

    V. del Pizzo; B. Luther-Davies

    1979-01-01

    The thresholds for self-focusing of a laser beam in a laser-produced plasma computed for propagation of a nanosecond duration pulses in short, high density multiply ionized absorbing plasmas are reported. Theoretical treatment of self-focusing used a computational model TRSF (Siegrist, 1976) to calculate the self-focusing behavior of a laser beam which is Gaussian in time and space and propagating through

  6. Optical emission from laser-produced chromium and magnesium plasma under the effect of two sequential laser pulses

    Microsoft Academic Search

    V. N. Rai; F. Y Yueh; J. P. Singh

    2005-01-01

    Parametric study of optical emission from two successive laser pulses produced chromium and magnesium plasma is presented. The line emission from chromium and magnesium plasma showed an increase by more than six times for double laser pulse excitation than for single-pulse excitation. An optimum increase in emission intensity was noted for inter-pulse delay of sim2-3 mus for all the elements.

  7. Optical emission from laser-produced chromium and magnesium plasma under the effect of two sequential laser pulses

    Microsoft Academic Search

    V. N. Rai; F. Y. Yueh; J. P. Singh

    2005-01-01

    Parametric study of optical emission from two successive laser pulses produced chromium and magnesium plasma is presented.\\u000a The line emission from chromium and magnesium plasma showed an increase by more than six times for double laser pulse excitation\\u000a than for single-pulse excitation. An optimum increase in emission intensity was noted for inter-pulse delay of ?23 ?s for\\u000a all the elements.

  8. An experimental investigation of refraction-induced distortions in harmonic-light images of laser-produced plasmas

    Microsoft Academic Search

    C. Darrow; D. S. Montgomery; K. Estabrook; R. P. Drake; G. E. Busch; E. F. Gabl

    1990-01-01

    In this paper the results of a simple experiment designed to study refraction-induced distortion of images of narrow-band-light-emitting regions in a laser-produced plasma are described. Source regions were formed by relaying the image of a backlit pinhole array into the plasma (25 μm-diam. pinhole; 30-ps, 0.25-μm backlighter beam). Images of these source regions were recorded on film and compared with

  9. An experimental investigation of refraction-induced distortions in harmonic-light images of laser-produced plasmas

    Microsoft Academic Search

    C. Darrow; D. S. Montgomery; K. Estabrook; R. P. Drake; G. E. Busch; E. F. Gabl

    1990-01-01

    In this paper the results of a simple experiment designed to study refraction-induced distortion of images of narrow-band-light-emitting regions in a laser-produced plasma are described. Source regions were formed by relaying the image of a backlit pinhole array into the plasma (25 ?m-diam. pinhole; 30-ps, 0.25-?m backlighter beam). Images of these source regions were recorded on film and compared with

  10. Excitation and Nonlinear Evolution of the Modified Simon-Hoh Instability in AN Electron Beam Produced Plasma Column

    Microsoft Academic Search

    Youichi Sakawa

    1992-01-01

    An intermediate frequency (f_{ci } < f < f_{ce}) electrostatic instability has been observed in an electron beam produced, cylindrical plasma column. We have identified this instability as a new instability, the Modified Simon-Hoh instability (MSHI), which has an instability mechanism similar to the Simon-Hoh instability (SHI). This instability can occur in a cylindrical collisionless plasma if a radial DC

  11. Initial design for an experimental investigation of strongly coupled plasma behavior in the Atlas facility

    SciTech Connect

    Munson, C.P.; Benage, J.F. Jr.; Taylor, A.J.; Trainor, R.J. Jr.; Wood, B.P.; Wysocki, F.J.

    1999-07-01

    Atlas is a high current ({approximately} 30 MA peak, with a current risetime {approximately} 4.5 {micro}sec), high energy (E{sub stored} = 24 MJ, E{sub load} = 3--6 MJ), pulsed power facility which is being constructed at Los Alamos National Laboratory with a scheduled completion date in the year 2000. When operational, this facility will provide a platform for experiments in high pressure shocks (> 20 Mbar), adiabatic compression ({rho}/{rho}{sub 0} > 5, P > 10 Mbar), high magnetic fields ({approximately} 2,000 T), high strain and strain rates ({var_epsilon} > 200%, d{var_epsilon}/dt {approximately} 10{sup 4} to 10{sup 6} s{sup {minus}1}), hydrodynamic instabilities of materials in turbulent regimes, magnetized target fusion, equation of state, and strongly coupled plasmas. For the strongly coupled plasma experiments, an auxiliary capacitor bank will be used to generate a moderate density (< 0.1 solid), relatively cold ({approximately} 1 eV) plasma by ohmic heating of a conducting material of interest such as titanium. This stargate plasma will be compressed against a central column containing diagnostic instrumentation by a cylindrical conducting liner that is driven radially inward by current from the main Atlas capacitor bank. The plasma is predicted to reach densities of {approximately} 1.1 times solid, achieve ion and electron temperatures of {approximately} 10 eV, and pressures of {approximately} 4--5 Mbar. This is a density/temperature regime which is expected to experience strong coupling, but only partial degeneracy. X-ray radiography is planned for measurements of the material density at discrete times during the experiments; diamond Raman measurements are anticipated for determination of the pressure. In addition, a neutron resonance spectroscopic technique is being evaluated for possible determination of the temperature (through low percentage doping of the titanium with a suitable resonant material). Initial target plasma formation experiments are being planned on an existing pulsed power facility at LANL and will be completed before the start of operation of Atlas.

  12. Modification of Nanofiltration Membranes by Surface-Initiated Atom Transfer Radical Polymerization for Produced Water Filtration

    Microsoft Academic Search

    Namrata Tomer; Subrata Mondal; Daniel Wandera; S. Ranil Wickramasinghe; Scott M. Husson

    2009-01-01

    Poly(N-isopropylacrylamide) and poly(N-isopropylacrylamide-block-ethylene glycol methacrylate) were grafted from commercial polyamide thin-film composite nanofiltration membranes using surface-initiated atom transfer radical polymerization. The results from Fourier-transform infrared spectroscopy confirmed the successful grafting of both polymers from the membrane surfaces. Contact angle measurements were done to illustrate the temperature responsive wettability of the modified membrane surfaces. Modified membranes were used in flux measurements

  13. Measurements of ion temperature and flow of pulsed plasmas produced by a magnetized coaxial plasma gun device using an ion Doppler spectrometer

    NASA Astrophysics Data System (ADS)

    Kitagawa, Y.; Sakuma, I.; Iwamoto, D.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

    2012-10-01

    It is important to know surface damage characteristics of plasma-facing component materials during transient heat and particle loads such as type I ELMs. A magnetized coaxial plasma gun (MCPG) device has been used as transient heat and particle source in ELM simulation experiments. Characteristics of pulsed plasmas produced by the MCPG device play an important role for the plasma material interaction. In this study, ion temperature and flow velocity of pulsed He plasmas were measured by an ion Doppler spectrometer (IDS). The IDS system consists of a light collection system including optical fibers, 1m-spectrometer and a 16 channel photomultiplier tube (PMT) detector. The IDS system measures the width and Doppler shift of HeII (468.58 nm) emission line with the time resolution of 1 ?s. The Doppler broadened and shifted spectra were measured with 45 and 135 degree angles with respect to the plasmoid traveling direction. The observed emission line profile was represented by sum of two Gaussian components to determine the temperature and flow velocity. The minor component at around the wavelength of zero-velocity was produced by the stationary plasma. As the results, the ion velocity and temperature were 68 km/s and 19 eV, respectively. Thus, the He ion flow energy is 97 eV. The observed flow velocity agrees with that measured by a time of flight technique.

  14. The application of photoconductive detectors to the measurement of x-ray production in laser produced plasmas

    SciTech Connect

    Kania, D.R.; Bell, P.; Trebes, J.

    1987-08-01

    Photoconductive detectors (PCDs) offer an attractive alternative for the measurement of pulsed x-rays from laser produced plasmas. These devices are fast (FWHM approx.100 ps), sensitive and simple to use. We have used InP, GaAs, and Type IIa diamond as PCDs to measure x-rays emission from 100 eV to 100 keV. Specifically, we have used these detectors to measure total radiation yields, corona temperatures, and hot electron generated x-rays from laser produced plasmas. 5 refs., 4 figs.

  15. Coherent control of intense terahertz radiation in laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Kim, Ki-Yong

    2008-11-01

    Intense, broadband terahertz (THz) pulse generation is of great current interest owing to its potential application in nonlinear THz optics and spectroscopy. Although such intense THz radiation exceeding tens of microjoules can be obtained from large-scale electron accelerator facilities such as free electron lasers and synchrotrons, there is a present and growing need for high-energy, compact THz sources at a tabletop- scale. One potential scheme is using tabletop, femtosecond, terawatt lasers to produce tenuous plasmas for scalable THz generation. Recently, intense THz generation has been observed upon mixing a femtosecond laser's fundamental and second harmonic fields in gases. The underlying mechanism has been examined and now understood in the context of a plasma current model. In this model, a transverse asymmetric electron current arises when the bound electrons undergo rapid tunneling ionization and acceleration in the two-color field. Since this current surge occurs on the timescale of the laser pulse duration, in the case of ultrafast lasers (<100 fs), this process can generate electromagnetic radiation at THz frequencies. Experimentally, we have recently demonstrated a high-energy (>5 microjoule), super-broadband tabletop source generating ultrafast THz pulses (>75 THz) in gases via two- color photoionization [1]. We also observed strongly anti- correlated third harmonic radiation. By controlling the relative phase between two-color fields, we can switch the output energy between THz and third harmonic [1]. Our current model can be applied to explain this phase-sensitive control, as well as to characterize the carrier envelope phase of few- cycle laser pulses undergoing ultrafast tunneling ionization. [0pt] [1] K. Y. Kim et al., Nature Photonics, doi:10.1038/nphoton.2008.153 (2008)

  16. An experimental investigation of refraction-induced distortions in harmonic-light images of laser-produced plasmas

    SciTech Connect

    Darrow, C.; Montgomery, D.S.; Estabrook, K.; Drake, R.P. (Lawrence Livermore National Laboratory, Box 808, Livermore, California 94550 (USA)); Busch, G.E.; Gabl, E.F. (KMS Fusion Inc., 3621 South State Road, Ann Arbor, Michigan 48106 (USA))

    1990-04-15

    In this paper the results of a simple experiment designed to study refraction-induced distortion of images of narrow-band-light-emitting regions in a laser-produced plasma are described. Source regions were formed by relaying the image of a backlit pinhole array into the plasma (25 {mu}m-diam. pinhole; 30-ps, 0.25-{mu}m backlighter beam). Images of these source regions were recorded on film and compared with and without plasma present. Refraction effects, evidenced by translation of the apparent pinhole locations and blurring of the pinhole spots, are compared for different plasma sizes and for different delays of the backlighter pulse with respect to the plasma-production laser pulse. These results were then compared with expectations based on numerical raytraces through a plasma-density profile derived from a hydrodynamic simulation of our exploding-foil plasma. The significance of these results in the imaging of harmonic and half-harmonic light as a plasma-density diagnostic is discussed. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48.

  17. Investigation on recovery of gap insulation strength and EUV radiation in the post-discharge stage of a laser-triggered discharge produced tin plasma EUV source

    NASA Astrophysics Data System (ADS)

    Lu, P.; Kitajima, S.; Lim, S.; Katsuki, S.; Akiyama, H.; Teramoto, Y.

    2014-10-01

    This paper presents an investigation on the recovery of gap insulation strength and extreme ultraviolet (EUV) radiation in the post-discharge stage of a laser-triggered discharge produced tin plasma (LTDPP) EUV source. Gap insulation strength recovers more quickly under a shorter gap length. The gap breakdown voltage recovered to 19.4?kV with a breakdown probability of 25% at 80?s after an 8?J discharge under a 2.5?mm gap. The same discharge energy under a 5?mm gap required 140?s for equal recovery. The EUV radiation recovery process was measured utilizing a double laser triggered discharge system. EUV radiation recovery lagged behind the gap insulation strength recovery for both the 2.5 and 5?mm gap. In the case of the 8?J input pulse energy, EUV radiation recovered to the same level as the first EUV pulse at about 600 and 160?s for the 5 and 2.5?mm gaps, corresponding to a 1.67?kHz and 6.25?kHz repetition rate, respectively. In the case of the 2.5?mm gap and 4?J input pulse energy, our EUV source could work with a repetition rate of upto 23?kHz, enabling the EUV output to reach 345?W/2?sr which was 4.5 times as the value of the 5?mm gap and 8?J input energy. To discuss the slower EUV radiation process, the initial laser trigger phase and plasma pinch stage during the first and second laser-triggered discharge were visualized by means of high speed visible light imaging and laser Schlieren imaging. Comparative results suggest that tin droplets influenced the initial laser-produced plasma plume, consequently affecting the Z-pinch plasma dynamics and its EUV radiation which resulted in the delayed EUV recovery process.

  18. ROLE OF INITIAL SUCROSE AND PH LEVELS ON NATURAL, HYDROGEN-PRODUCING, ANAEROBE GERMINATION

    Microsoft Academic Search

    Steven Van Ginkel; ShihWu Sung; Ling Li

    2001-01-01

    Anaerobic batch cultures were established to assess natural anaerobic sporulation, germination, and hydrogen production. Heat-shocked soil inocula obtained from a potato field was cultured using sucrose as the substrate. Eleven batch experimental results suggested that baking was an excellent heat-shock treatment to select for spore forming hydrogen-producing bacteria i.e. clostridia from the soil. Sucrose could induce clostridial spore germination and

  19. Plasma Membrane Potential Oscillations in Insulin Secreting Ins-1 832/13 Cells Do Not Require Glycolysis and Are Not Initiated by Fluctuations in Mitochondrial Bioenergetics*

    PubMed Central

    Goehring, Isabel; Gerencser, Akos A.; Schmidt, Sara; Brand, Martin D.; Mulder, Hindrik; Nicholls, David G.

    2012-01-01

    Oscillations in plasma membrane potential play a central role in glucose-induced insulin secretion from pancreatic ?-cells and related insulinoma cell lines. We have employed a novel fluorescent plasma membrane potential (??p) indicator in combination with indicators of cytoplasmic free Ca2+ ([Ca2+]c), mitochondrial membrane potential (??m), matrix ATP concentration, and NAD(P)H fluorescence to investigate the role of mitochondria in the generation of plasma membrane potential oscillations in clonal INS-1 832/13 ?-cells. Elevated glucose caused oscillations in plasma membrane potential and cytoplasmic free Ca2+ concentration over the same concentration range required for insulin release, although considerable cell-to-cell heterogeneity was observed. Exogenous pyruvate was as effective as glucose in inducing oscillations, both in the presence and absence of 2.8 mm glucose. Increased glucose and pyruvate each produced a concentration-dependent mitochondrial hyperpolarization. The causal relationships between pairs of parameters (??p and [Ca2+]c, ??p and NAD(P)H, matrix ATP and [Ca2+]c, and ??m and [Ca2+]c) were investigated at single cell level. It is concluded that, in these ?-cells, depolarizing oscillations in ??p are not initiated by mitochondrial bioenergetic changes. Instead, regardless of substrate, it appears that the mitochondria may simply be required to exceed a critical bioenergetic threshold to allow release of insulin. Once this threshold is exceeded, an autonomous ??p oscillatory mechanism is initiated. PMID:22418435

  20. Laser wavelength effects on the charge state resolved ion energy distributions from laser-produced Sn plasma

    E-print Network

    Najmabadi, Farrokh

    state, and all ion energies greatly exceed the initial thermal electron temperature. The differences CO2 lasers and 1.064 m neodymium-doped yttrium aluminum garnet Nd:YAG la- sers are current topics wavelength on the properties of the ions emitted by the plasma are of par

  1. Increased plasma atrial natriuretic factor in catecholamine-producing tumor patients.

    PubMed

    Puy, A M; Levin, G M; Armando, I; Donoso, A S; Fernndez, B E; Barontini, M B

    1999-10-01

    The aim of this study was to evaluate plasma levels of ANF in patients with catecholamine-secreting tumors with and without hypertension and to relate ANF secretion to levels of plasma and urinary catecholamines and blood pressure. Twenty-one pheochromocytoma (15 with sustained, 6 with paroxysmal hypertension), 6 neuroblastoma (1 hypertensive) patients and 28 aged-matched controls were studied in basal conditions. Plasma and urinary norepinephrine (NE),epinephrine (E), dopamine (DA) and DOPA were determined by HPLC-ED and plasma ANF by RIA. Both neuroblastoma and pheochromocytoma patients had significantly higher plasma ANF levels than controls. Neuroblastomas showed higher ANF concentration than pheochromocytomas. No differences were found in plasma ANF between hypertensive and normotensive patients. Pheochromocytomas with ANF levels within the normal range had plasma and urinary NE and urinary DA and DOPA levels significantly higher than patients with high ANF. Plasma ANF levels were unrelated to systolic or diastolic blood pressure or heart rate. A negative correlation between plasma ANF and urinary DA was found only in the patients groups. In conclusion, plasma ANF was increased in pheochromocytoma and neuroblastoma patients. Our data suggest that the excessive catecholamine secretion is not responsible for the increased ANF secretion in these patients. The significance of the relationships among plasma ANF and urinary and plasma catecholamines requires further investigation. PMID:10513832

  2. Degradation of carbon-based materials under ablative conditions produced by a high enthalpy plasma jet

    Microsoft Academic Search

    Gilberto Petraconi; Alexei Mikhailovich Essiptchouk; Leonid Ivanovich Charakhovski; Choyu Otani; Homero Santiago Maciel; Rodrigo Svio Pessoa; Maria Luisa Gregori; Snia Fonseca Costa

    2010-01-01

    A stationary experiment was performed to study the degradation of carbon-based materials by immersion in a plasma jet. In the experiment, graphite and C\\/C composite were chosen as the target materials, and the reactive plasma jet was generated by an air plasma torch. For macroscopic study of the material degradation, the sample's mass losses were measured as function of the

  3. Alternative Translation Initiation Produces a Short Form of a Spore Coat Protein in Bacillus subtilis

    PubMed Central

    Ozin, Amanda J.; Costa, Teresa; Henriques, Adriano O.; Moran, Charles P.

    2001-01-01

    During endospore formation in Bacillus subtilis, over two dozen polypeptides are localized to the developing spore and coordinately assembled into a thick multilayered structure called the spore coat. Assembly of the coat is initiated by the expression of morphogenetic proteins SpoIVA, CotE, and SpoVID. These morphogenetic proteins appear to guide the assembly of other proteins into the spore coat. For example, SpoVID forms a complex with the SafA protein, which is incorporated into the coat during the early stages of development. At least two forms of SafA are found in the mature spore coat: a full-length form and a shorter form (SafA-C30) that begins with a methionine encoded by codon 164 of safA. In this study, we present evidence that the expression of SafA-C30 arises from translation initiation at codon 164. We found only a single transcript driving expression of SafA. A stop codon engineered just upstream of a predicted ribosome-binding site near codon M164 abolished formation of full-length SafA, but not SafA-C30. The same effect was observed with an alanine substitution at codon 1 of SafA. Accumulation of SafA-C30 was blocked by substitution of an alanine codon at codon 164, but not by a substitution at a nearby methionine at codon 161. We found that overproduction of SafA-C30 interfered with the activation of late mother cell-specific transcription and caused a strong sporulation block. PMID:11222602

  4. Spectroscopic and interferometric measurements of laser-plasma produced blast waves

    NASA Astrophysics Data System (ADS)

    McLean, E. A.; Stamper, J. A.; Manka, C. K.; Griem, H. R.; Ali, A. W.; Ripin, B. H.

    1986-08-01

    A laser-produced plasma generates blast waves as it expands supersonically into a stationary photoionized background gas (N2) at a pressure of 1-5 Torr.1 Using a combination of spectroscopic and interferometric measurements, time- and space-resolved values of the temperature and density are obtained. This study was performed on targets in the NRL Pharos III laser facility with laser energies of 20-120 J and pulse durations of 5 ns. A 1-m spectrograph equipped with three photomultiplier channels, which are calibrated on an absolute scale, is used for the spectroscopic measurements. The interferometry is done with a folded-wavefront interferometer. It uses an optical probe pulse at 5270 that is split off of the main laser pulse, reduced in pulse duration (300 ps), and time delayed. Interferometric measurements can be made simultaneously with the spectroscopic measurements. Experimental data and the technique of analysis will be shown. This work was supported by the Defense Nuclear Agency.

  5. Rapid, Absolute Calibration of X-ray Filters Employed By Laser-Produced Plasma Diagnostics

    SciTech Connect

    Brown, G V; Beiersdorfer, P; Emig, J; Frankel, M; Gu, M F; Heeter, R F; Magee, E; Thorn, D B; Widmann, K; . Kelley, R L; Kilbourne, C A; Porter, F S

    2008-05-11

    The electron beam ion trap (EBIT) facility at the Lawrence Livermore National Laboratory is being used to absolutely calibrate the transmission efficiency of X-ray filters employed by diodes and spectrometers used to diagnose laser-produced plasmas. EBIT emits strong, discrete monoenergetic lines at appropriately chosen X-ray energies. X-rays are detected using the high-resolution EBIT calorimeter spectrometer (ECS), developed for LLNL at the NASA/Goddard Space Flight Center. X-ray filter transmission efficiency is determined by dividing the X-ray counts detected when the filter is in the line of sight by those detected when out of the line of sight. Verification of filter thickness can be completed in only a few hours, and absolute efficiencies can be calibrated in a single day over a broad range from about 0.1 to 15 keV. The EBIT calibration lab has been used to field diagnostics (e.g., the OZSPEC instrument) with fully calibrated X-ray filters at the OMEGA laser. Extensions to use the capability for calibrating filter transmission for the DANTE instrument on the National Ignition Facility are discussed.

  6. Rapid, absolute calibration of x-ray filters employed by laser-produced plasma diagnostics

    SciTech Connect

    Brown, G. V.; Beiersdorfer, P.; Emig, J.; Frankel, M.; Gu, M. F.; Heeter, R. F.; Magee, E.; Thorn, D. B.; Widmann, K. [Department of Physical Sciences, High Energy Density Physics and Astrophysics Division, Lawrence Livermore National Laboratory, 7000 East Avenue, L-260, Livermore, California 94550 (United States); Kelley, R. L.; Kilbourne, C. A.; Porter, F. S. [NASA/Goddard Space Flight Center, Greenbelt, Maryland 20770 (United States)

    2008-10-15

    The Electron Beam Ion Trap (EBIT) facility at the Lawrence Livermore National Laboratory is being used to absolutely calibrate the transmission efficiency of x-ray filters employed by diodes and spectrometers used to diagnose laser-produced plasmas. EBIT emits strong, discrete monoenergetic lines at appropriately chosen x-ray energies. X rays are detected using the high resolution EBIT Calorimeter Spectrometer (ECS), developed for LLNL at the NASA/Goddard Space Flight Center. X-ray filter transmission efficiency is determined by dividing the x-ray counts detected when the filter is in the line of sight by those detected when out of the line of sight. Verification of filter thickness can be completed in only a few hours, and absolute efficiencies can be calibrated in a single day over a broad range from about 0.1 to 15 keV. The EBIT calibration lab has been used to field diagnostics (e.g., the OZSPEC instrument) with fully calibrated x-ray filters at the OMEGA laser. Extensions to use the capability for calibrating filter transmission for the DANTE instrument on the National Ignition Facility are discussed.

  7. Intense electron emission due to picosecond laser-produced plasmas in high gradient electric fields

    SciTech Connect

    Wang, X.J.; Tsang, T.; Kirk, H.; Srinivasan-Rao, T.; Fischer, J.; Batchelor, K.; Russell, P.; Fernow, R.C. (Brookhaven National Laboratory, Upton, New York 11973 (United States))

    1992-08-01

    Picosecond laser pulses at a wavelength of 266 nm have been focused onto a solid metal cathode in coincidence with high gradient electric fields to produce high brightness electron beams. At power densities exceeding 10{sup 9} W/cm{sup 2}, a solid density plasma is formed and intense bursts of electrons are emitted from the target accompanied by macroscopic surface damage. An inferred {similar to}1 {mu}C of integrated charge with an average current of {similar to}20 A is emitted from a radio-frequency cavity driven at electric field gradients of {similar to}80 MV/m. In another experiment, where a dc extraction field of {similar to}6 MV/m is used, we observed an electron charge of {similar to}0.17 {mu}C. Both results are compared with the Schottky effect and the Fowler--Nordheim field emission. We found that this laser-induced intense electron emission shares many features with the explosive electron emission processes. No selective wavelength dependence is observed in the production of the intense electron emission in the dc extraction field. The integrated electrons give an apparent quantum efficiency of {similar to}1.2%, which is one of the highest reported to date from metal photocathodes at these photon energies.

  8. Spectral and temporal characterization of nanosecond and femtosecond laser produced plasma from metallic targets

    E-print Network

    Smijesh, N

    2015-01-01

    Experimental characterization and comparison of the temporal features of plasma produced by ultrafast (100 fs, 800 nm) and short-pulse (7ns, 1064 nm) laser pulses from a high purity nickel and zinc targets, expanding into a nitrogen background, are presented. The experiment is carried out under a wide pressure range of 10^-6 to 10^2 Torr, where the plume intensity is found to increase rapidly when the pressure approaches 1 Torr. Electron temperature (Te) is calculated from OES and is found to be independent of pressure for ultrafast excitation, whereas an enhancement in Te is observed around milliTorr regime for short-pulse excitation.The velocity measurements indicate acceleration of the fast species to a certain distance upon plume expansion, whereas the slow species are found to decelerate, particularly at higher pressures.A comparison of the time of flight dynamics of neutrals and ions in the LPPs generated by intense laser pulses confirms that the fast species observed are due to the recombination of fas...

  9. Characterization of gas targets for laser produced extreme ultraviolet plasmas with a Hartmann-Shack sensor

    SciTech Connect

    Peth, Christian; Kranzusch, Sebastian; Mann, Klaus; Vioel, Wolfgang [Laser-Laboratorium Goettingen e. V., Hans-Adolf-Krebs-Weg 1, D-37077 Goettingen (Germany); Fachhochschule Hildesheim/Holzminden/Goettingen, Fakultaet Naturwissenschaften und Technik, Von-Ossietzky-Str. 99, D-37085 Goettingen (Germany)

    2004-10-01

    A table top extreme ultraviolet (EUV)-source was developed at Laser-Laboratorium Goettingen for the characterization of optical components and sensoric devices in the wavelength region from 11 to 13 nm. EUV radiation is generated by focusing the beam of a Q-switched Nd:YAG laser into a pulsed xenon gas jet. Since a directed gas jet with a high number density is needed for an optimal performance of the source, conical nozzles with different cone angles were drilled with an excimer laser to produce a supersonic gas jet. The influence of the nozzle geometry on the gas jet was characterized with a Hartmann-Shack wave front sensor. The deformation of a planar wave front after passing the gas jet was analyzed with this sensor, allowing a reconstruction of the gas density distribution. Thus, the gas jet was optimized resulting in an increase of EUV emission by a factor of two and a decrease of the plasma size at the same time.

  10. Laser-produced plasma measurement of thermal diffusivity of molten metals

    SciTech Connect

    Kim, Yong W.; Park, C.S. [Lehigh Univ., Bethlehem, PA (United States)

    1995-12-01

    We have shown that a laser-produced plasma plume which is representative in composition of the condensed phase target can be reproducibly generated if the movement of the surface due to evaporation is kept in pace with the thermal diffusion front propagating into the bulk. The resulting mass loss is then strongly controlled by the thermal diffusivity of the target matter, and this relationship has been exploited to measure the thermal diffusivity of metallic alloys. We have developed a novel RF levitator-heater as a contamination-free molten metal source to be used as a target for LPP plume generation. In order to determine the mass loss due to LPP excitation, a new high sensitivity transducer has been constructed for measurement of the resulting impulse imparted on the specimen. The impulse transducer is built onto the specimen holder within the levitation-assisted molten metal source. The LPP method has been fully excercised for measurement of the thermal diffusivity of a molten specimen relative to the value for its room temperature solid. The results for SS304 and SS316 are presented together with a critique of the results. A numerical modeling of specimen heating in the molten metal source and the physical basis of the new hod are also presented.

  11. Instantaneous x-ray radiation energy from laser produced polystyrene plasmas for shock ignition conditions

    SciTech Connect

    Shang, Wanli; Wei, Huiyue; Li, Zhichao; Yi, Rongqing; Zhu, Tuo; Song, Tianmin; Huang, Chengwu; Yang, Jiamin [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China)] [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China)

    2013-10-15

    Laser target energy coupling mechanism is crucial in the shock ignition (SI) scheme, and x-ray radiation energy is a non-negligible portion of the laser produced plasma energy. To evaluate the x-ray radiation energy amount at conditions relevant to SI scheme, instantaneous x-ray radiation energy is investigated experimentally with continuum phase plates smoothed lasers irradiating layer polystyrene targets. Comparative laser pulses without and with shock spike are employed. With the measured x-ray angular distribution, full space x-ray radiation energy and conversion efficiency are observed. Instantaneous scaling law of x-ray conversion efficiency is obtained as a function of laser intensity and time. It should be pointed out that the scaling law is available for any laser pulse shape and intensity, with which irradiates polystyrene planar target with intensity from 2 10{sup 14} to 1.8 10{sup 15} W/cm{sup 2}. Numerical analysis of the laser energy transformation is performed, and the simulation results agree with the experimental data.

  12. Measurements of Electron Temperature and Density Profiles of Plasmas Produced by Nike KrF Laser for Laser Plasma Instability (LPI) Research

    NASA Astrophysics Data System (ADS)

    Oh, Jaechul; Weaver, J. L.; Obenschain, S. P.; Schmitt, A. J.; Kehne, D. M.; Karasik, M.; Chan, L.-Y.; Serlin, V.; Phillips, L.

    2012-10-01

    ExperimentsfootnotetextJ. Oh, et al, GO5.4, APS DPP (2010).^,footnotetextJ. L. Weaver, et al, GO5.3, APS DPP (2010). using Nike KrF laser observed LPI signatures from CH plasmas at the laser intensities above 1x10^15 W/cm^2. Knowing spatial profiles of temperature (Te) and density (ne) in the underdense coronal region (0 < n < nc/4) of the plasma is essential to understanding the LPI observation. However, numerical simulation was the only way to access the profiles for the previous experiments. In the current Nike LPI experiment, a side-on grid imaging refractometer (GIR)footnotetextR. S. Craxton, et al, Phys. Fluids B 5, 4419 (1993). is being deployed for measuring the underdense plasma profiles. The GIR will resolve Te and ne in space taking a 2D snapshot of probe laser (?= 263 nm, ?t = 10 psec) beamlets (50?m spacing) refracted by the plasma at a selected time during the laser illumination. Time-resolved spectrometers with an absolute-intensity-calibrated photodiode array and a streak camera will simultaneously monitor light emission from the plasma in spectral ranges relevant to Raman (SRS) and two plasmon decay (TDP) instabilities. The experimental study of effects of the plasma profiles on the LPI initiation will be presented.

  13. Pump-probe imaging of nanosecond laser-induced bubbles in distilled water solutions: Observations of laser-produced-plasma

    SciTech Connect

    Evans, R.; Camacho-Lopez, S. [Departamento de Optica, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Carratera Ensenada-Tijuana No. 3918, Zona Playitas, C.P. 22860, Ensenada, B. C. Mexico (Mexico)

    2010-11-15

    This article presents the analysis of the laser-produced-plasma (LPP) formed by the focusing of a 9 ns laser pulse, {lambda}=532 nm, with a NA=0.6 aspherical lens using energies between 100-1500 {mu}J, into distilled water with varying solutions of table salt. Observations of the filamentation plasma were made, which are explained by self-focusing of the laser pulse by the LPP through ponderomotive cavitation of the electron plasma in the center of the beam. The filamentation of the beam through a low density plasma wave guide explains why the transmission of the pump laser through the interaction region was notably higher on previous experiments that we performed [R. Evans et al., Opt. Express 16, 7481 (2008)], than a very similar set of experiments performed by Noack and Vogel [IEEE J. Quantum Electron. 35, 1156 (1999)].

  14. Nonthermal Biological Treatments Using Discharge Plasma Produced by Pulsed Power 4. Cleaning of Lakes and Marshes by Pulsed Power Produced Streamer Discharges in Water

    NASA Astrophysics Data System (ADS)

    Akiyama, Hidenori; Katsuki, Sunao; Namihira, Takao; Ishibashi, Kazuo; Kiyosaki, Noriaki

    Pulsed power has been used to produce non-thermal plasmas in atmospheric pressure gases that generate a high electric field at the tips of streamer discharges, where high energy electrons, free radicals, ultraviolet rays, and ozone are produced. These manifestations of streamer discharges have been used in the treatment of exhaust gases, removal of volatile and toxic compounds such as dioxin, and the sterilization of microorganisms. Here, large volume streamer discharges in water are described. These streamer discharges in liquids are able to produce a high electric field, high energy electrons, ozone, chemically active species, ultraviolet rays, and shock waves, which readily sterilize microorganisms and decompose molecules and materials. An application of this phenomenon to the cleaning of lakes and marshes is also described.

  15. Charged-particle acceleration and energy loss in laser-produced plasmas D. G. Hicks,a)

    E-print Network

    Charged-particle acceleration and energy loss in laser-produced plasmas D. G. Hicks,a) C. K. Li, F, particle energy shifts were dominated by acceleration effects. Using a simple model for the accelerating T. R. Boehly et al., Opt. Commun. 133, 495 1997 . Comparing the energy shifts of four particle types

  16. ccsd-00001731,version2-7Nov2004 Study on high pressure plasma produced by ArF

    E-print Network

    Boyer, Edmond

    a high pressure gas is irradiated by a focused laser light, a hot and dense plasma is produced.[1. When the ArF laser light is irradiated in high pressure Ar gas up to 130 atm whose wavelength, and the laser light is focused at the center of the high pressure gas chamber by a lens with a focal length

  17. Persistence of uranium emission in laser-produced plasmas N. L. LaHaye, S. S. Harilal,a)

    E-print Network

    Harilal, S. S.

    Persistence of uranium emission in laser-produced plasmas N. L. LaHaye, S. S. Harilal,a) P. K; published online 22 April 2014) Detection of uranium and other nuclear materials is of the utmost importance of special nuclear materials (SNMs), such as uranium and thorium, is of particular interest to many agen

  18. Initial experimental results from a laboratory size beam plasma discharge device

    NASA Technical Reports Server (NTRS)

    Konradi, A.; Bernstein, W.; Bulgher, D. L.; Garrity, J. O.; Winkler, J. L.

    1983-01-01

    A laboratory beam plasma discharge (BPD) device produced BPD in N2, A, and He. All features of the BPD observed in the device agree with those observed in a large vacuum chamber. The empirical ignition criteria determined in the large chamber apply in the small device but do not fit when used for extrapolation between the large and the small geometry. At some energies and magnetic fields beam currents exist for which the total light output in the BPD state varies by a factor of 2 with a factor of 6 pressure variation. Above 0.0001 torr the BPD width is pressure independent but for lower pressures it expands by as much as a factor of 4 at 0.00002 torr.

  19. Observation and modelling of hollow multicharged ion x-ray spectra radiated by laser produced plasma

    SciTech Connect

    Colgan, James P [Los Alamos National Laboratory; Abdallah, Joseph [Los Alamos National Laboratory; Faenov, A Ya [JAPAN/RUSSIA; Pikuz, T A [JAPAN/RUSSIA; Akobelev, I Yu [JAPAN/RUSSIA; Fukuda, Y [JAPAN/RUSSIA

    2008-01-01

    The role of the highly charged hollow ions in the X-Ray emission plasma spectTa is investigated for 2 cases: (1) plasma obtained under inadiation of Ar clusters by ultrashort laser pulses and (2) Mg-plasma heated by a short-wavelength long (nanosecond) laser pulse. Experimental measurements are presented. Calculations in support of these measurements have been performed using a detailed atomic kinetics model with the ion distributions found from solution of the time-dependent rate equations.

  20. X-ray characterization of high energy density plasmas produced in mega-joule laser experiments on the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Glenzer, Siegfried

    2010-03-01

    With completion of the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory the quest for producing a burning fusion plasma has begun. The goal of these experiments is to compress matter to densities and temperatures higher than the interior of the sun to initiate nuclear fusion and burn of hydrogen isotopes. In the first indirect-drive hohlraum experiments on NIF, we have demonstrated symmetric capsule implosions at unprecedented conditions of mega-joule laser energies. 192 simultaneously fired laser beams heat ignition hohlraums to radiation temperatures of 3.3 million Kelvin compressing 2-millimeter capsules by the soft x rays produced inside the hohlraum. In these experiments, symmetry and velocity of the implosion are measured by imaging the 9 keV capsule x-ray emission on a temporally resolving 2-D detector. In addition, x-ray radiography and scattering techniques are being developed for measuring the density and temperature of the implosion. The experiments indicate conditions suitable for compressing deuterium-tritium filled capsules with the goal to produce burning fusion plasmas in the laboratory.

  1. Development of a Laser-Produced Plasma X-ray source for Phase-Contrast Radiography of DT Ice layers

    SciTech Connect

    Izumi, N; Dewald, E; Kozioziemski, B; Landen, O L; Koch, J A

    2008-07-21

    Refraction enhanced x-ray phase contrast imaging is crucial for characterization of deuterium-tritium (DT) ice layer roughness in optically opaque inertial confinement fusion capsules. To observe the time development of DT ice roughness over {approx} second timescales, we need a bright x-ray source that can produce an image faster than the evolution of the ice surface roughness. A laser produced plasma x-ray source is one of the candidates that can meet this requirement. We performed experiments at the Janus laser facility at Lawrence Livermore National Laboratory and assessed the characteristics of the laser produced plasma x-ray source as a potential backlight for in situ target characterization.

  2. Excitation wavelength dependence of water-window line emissions from boron-nitride laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Crank, M.; Harilal, S. S.; Hassan, S. M.; Hassanein, A.

    2012-02-01

    We investigated the effects of laser excitation wavelength on water-window emission lines of laser-produced boron-nitride plasmas. Plasmas are produced by focusing 1064 nm and harmonically generated 532 and 266 nm radiation from a Nd:YAG laser on BN target in vacuum. Soft x-ray emission lines in the water-window region are recorded using a grazing-incidence spectrograph. Filtered photodiodes are used to obtain complementary data for water-window emission intensity and angular dependence. Spectral emission intensity changes in nitrogen Ly-? and He-? are used to show how laser wavelength affects emission. Our results show that the relative intensity of spectral lines is laser wavelength dependent, with the ratio of Ly-? to He-? emission intensity decreasing as laser wavelength is shortened. Filtered photodiode measurements of angular dependence showed that 266 and 532 nm laser wavelengths produce uniform emission.

  3. Recent progress in space- and time-resolved x-ray spectroscopy of laser-produced plasmas (abstract)

    NASA Astrophysics Data System (ADS)

    Young, B. K. F.

    1990-10-01

    New diagnostic techniques have provided measurement of relatively gradient-free x-ray spectra from high-powered laser-produced plasmas. Simultaneously space- and time-resolved x-ray spectra were measured from a variety of microdot plasmas using an array of multiframe, imaging, electronically gated x-ray crystal spectrometers with 100 ps time resolution. A multiframed, multicolored gated x-ray pinhole camera provided measurement of the plasma uniformity. A four-frame holographic interferometer was used to measure the electron density profile. Conventional x-ray streaked crystal spectrographs, spatially resolved x-ray (film) spectrometer, and pinhole cameras supplemented these new diagnostics. The instruments allow detailed studies of both the population kinetics of highly charged ions in dense plasmas and the hydrodynamics of laser-produced plasmas for the first time. The new diagnostics are described including data from ongoing experiments. Work was performed in part under the auspices of the U.S. Dept. of Energy by LLNL under Contract No. W-7405-Eng-48.

  4. Solution of the explosive percolation quest. II. Infinite-order transition produced by the initial distributions of clusters

    E-print Network

    R. A. da Costa; S. N. Dorogovtsev; A. V. Goltsev; J. F. F. Mendes

    2015-03-31

    We describe the effect of power-law initial distributions of clusters on ordinary percolation and its generalizations, specifically, models of explosive percolation processes based on local optimization. These aggregation processes were shown to exhibit continuous phase transitions if the evolution starts from a set of disconnected nodes. Since the critical exponents of the order parameter in explosive percolation transitions turned out to be very small, these transitions were first believed to be discontinuous. In this article we analyze the evolution starting from clusters of nodes whose sizes are distributed according to a power law. We show that these initial distributions change dramatically the position and order of the phase transitions in these problems. We find a particular initial power-law distribution producing a peculiar effect on explosive percolation, namely before the emergence of the percolation cluster, the system is in a "critical phase" with an infinite generalized susceptibility. This critical phase is absent in ordinary percolation models with any power-law initial conditions. The transition from the critical phase is an infinite order phase transition, which resembles the scenario of the Berezinskii-Kosterlitz-Thouless phase transition. We obtain the critical singularity of susceptibility at this peculiar infinite-order transition in explosive percolation. It turns out that the susceptibility in this situation does not obey the Curie-Weiss law.

  5. The critical ionization velocity as a mechanism for producing Titan's plasma tail

    Microsoft Academic Search

    A. A. Galeev; I. C. Chabibrachmanov

    1984-01-01

    The phenomenon of a critical ionization velocity may explain the anomalous interaction between the magnetospheric plasma corotating with Saturn and the atmosphere of Titan. Although the dominant role will be played by the lower-hybrid instability due to the counterstreaming of the magnetospehric plasma and newly formed atmospheric ions, charge-separation effects caused by the very large Larmor radius of the new

  6. Magnetic mirror confinement of laser-produced LiH plasmas

    Microsoft Academic Search

    R. G. Tomlinson; W. J. Fader; D. H. Polk; J. H. Stufflebeam

    1979-01-01

    Measurement results of the decay of mirror-confined lithium hydride plasmas are discussed with the density decay found to be quiescent for the first 250 microsec. Sudden increases in the plasma decay rate and in the RF emissions at the central cyclotron frequency of lithium ions were observed after the first 250 microseconds, interpreting them as evidence of the onset of

  7. Structural analysis of silicon dioxide and silicon oxynitride films produced using an oxygen plasma

    Microsoft Academic Search

    Octavian Buiu; Gary P. Kennedy; Mariuca Gartner; Stephen Taylor

    1998-01-01

    Plasma grown silicon dioxide and oxynitride layers are shown to represent, for microelectronic applications, a good alternative method to conventional thermally grown layers. Fast growth rates, together with good electrical properties are demonstrated, at low process temperatures. Growth kinetics of SiO2 layers synthesized both in RF and microwave plasma anodization systems are presented for a wide range of substrate temperatures

  8. Cold plasma technologies for the inactivation of human pathogens on fresh and fresh-cut produce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research in cold plasma processing at the USDAs Eastern Regional Research Center is focused on developing this technology into an effective tool to improve the safety of a variety of foods. Cold plasma applied to outbreak strains of Escherichia coli O157:H7 and Salmonella Stanley inoculated on the ...

  9. Characteristics and time evolution of a hollow cathode produced glow discharge plasma in air

    Microsoft Academic Search

    Joseph Atilla Gregor

    1997-01-01

    Current radar systems use mechanical directors and phased array technology for beam steering. Use of a sheet plasma as a microwave reflector promises several advantages over these methods. Operation is inherently broad-band, since all frequencies below the plasma frequency are reflected. The orientation and shape of the reflector may be changed directly through electronic control without resort to moving parts

  10. High density collimated beams of relativistic ions produced by petawatt laser pulses in plasmas

    Microsoft Academic Search

    Y. Sentoku; T. V. Liseikina; T. Zh. Esirkepov; F. Califano; N. M. Naumova; Y. Ueshima; V. A. Vshivkov; Y. Kato; K. Mima; K. Nishihara; F. Pegoraro; S. V. Bulanov

    2000-01-01

    Under optimal interaction conditions ions can be accelerated up to relativistic energies by a petawatt laser pulse in both underdense and overdense plasmas. Two-dimensional particle in cell simulations show that the laser pulse drills a channel through an underdense plasma slab due to relativistic self-focusing. Both ions and electrons are accelerated in the head region of the channel. However, ion

  11. Cold Plasma Inactivates Salmonella and Escherichia coli O157:H7 on Fresh Produce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This presentation will summarize recent advances in cold plasma technology at the USDAs Eastern Regional Research Center. Cold plasma generated in a gliding arc was applied to outbreak strains of Escherichia coli O157:H7 and Salmonella Stanley inoculated on the surfaces of golden delicious apples. ...

  12. The Influence of spot size on the expansion dynamics of nanosecond-laser-produced copper plasmas in atmosphere

    SciTech Connect

    Li, Xingwen; Wei, Wenfu; Wu, Jian; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, No. 28 XianNing West Road, Xi'an, Shaanxi Province 710049 (China)] [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, No. 28 XianNing West Road, Xi'an, Shaanxi Province 710049 (China)

    2013-06-28

    Laser produced copper plasmas of different spot sizes in air were investigated using fast photography and optical emission spectroscopy (OES). The laser energy was 33 mJ. There were dramatic changes in the plasma plume expansion into the ambient air when spot sizes changed from {approx}0.1 mm to {approx}0.6 mm. A stream-like structure and a hemispherical structure were, respectively, observed. It appeared that the same spot size resulted in similar expansion dynamics no matter whether the target was located in the front of or behind the focal point, although laser-induced air breakdown sometimes occurred in the latter case. Plasma plume front positions agree well with the classic blast wave model for the large spot-size cases, while an unexpected stagnation of {approx}80 ns occurred after the laser pulse ends for the small spot size cases. This stagnation can be understood in terms of the evolution of enhanced plasma shielding effects near the plasma front. Axial distributions of plasma components by OES revealed a good confinement effect. Electron number densities were estimated and interpreted using the recorded Intensified Charge Coupled Device (ICCD) images.

  13. Dependence of terahertz power from laser-produced plasma on laser intensity

    SciTech Connect

    Shin, J.-H.; Zhidkov, A.; Jin, Z.; Hosokai, T.; Kodama, R. [Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita, Osaka 565-0871 (Japan); Photon Pioneers Center, Osaka University, 2-1, Yamadaoka, Suita, Osaka 565-0871 (Japan); Japan Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka (Japan)

    2012-07-11

    Power of terahertz radiation from plasma which is generated from air irradiated by coupled ({omega}, 2{omega}) femtosecond laser pulses is analyzed for high laser intensities, for which non-linear plasma effects on the pulse propagation become essential, with multidimensional particle-in-cell simulations including the self-consistent plasma kinetics. The growth rate of THz power becomes slower as the laser intensity increases. A reason of such a lowering of efficiency in THz emission is found to be ionization of air by the laser pulse, which results in poor focusing of laser pulses.

  14. Soft-x-ray spectroscopy of subpicosecond laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Krushelnick, K. M.; Tighe, W.; Suckewer, S.

    1996-02-01

    Experiments that examine the interaction of high-intensity subpicosecond laser radiation ( \\similar 1018 W / cm2) with solid targets are performed. Soft-x-ray spectra from interactions with Teflon and aluminum targets that imply the creation of high-temperature ( > 200 eV) high-density ( > 10 23 cm -3 ) plasmas are obtained. Effects of a prepulse on the plasma characteristics are examined. The applicability of short, intense laser pulses for the formation of population inversions on x-ray transitions during recombination of high-density plasmas is discussed. 42.55.Vc.

  15. Potential formation in a collisionless plasma produced in an open magnetic field in presence of volume negative ion source

    NASA Astrophysics Data System (ADS)

    Phukan, Ananya; Goswami, K. S.; Bhuyan, P. J.

    2014-08-01

    The electric potential near a wall for a multi-species plasma with volume produced negative ions in presence of axially varying magnetic field is studied following an analytical-numerical approach. A constant negative ion source is assumed throughout the plasma volume, along with finite temperature positive ions and Boltzmann electrons. The particles are assumed to be guided by an open magnetic field that has its maximum at the centre, and field strength decreasing towards the walls. The one dimensional (1D) Poisson equation is derived using an analytical approach, and then solved numerically to study the potential profiles. Effect of (a) negative ion production rate, (b) magnetic field profile, and (c) negative ion temperature on the potential profile has been investigated. A potential peak appears near the wall when the negative ion temperature and density are sufficiently high. Also, the presence of negative ions further decreases the potential in the plasma region for a finite Debye Length (?D).

  16. Potential formation in a collisionless plasma produced in an open magnetic field in presence of volume negative ion source

    SciTech Connect

    Phukan, Ananya, E-mail: ananya.phukan26@gmail.com; Goswami, K. S.; Bhuyan, P. J. [Centre of Plasma Physics, Institute for Plasma Research Sonapur, Kamrup (M), Assam 782402 (India)

    2014-08-15

    The electric potential near a wall for a multi-species plasma with volume produced negative ions in presence of axially varying magnetic field is studied following an analytical-numerical approach. A constant negative ion source is assumed throughout the plasma volume, along with finite temperature positive ions and Boltzmann electrons. The particles are assumed to be guided by an open magnetic field that has its maximum at the centre, and field strength decreasing towards the walls. The one dimensional (1D) Poisson equation is derived using an analytical approach, and then solved numerically to study the potential profiles. Effect of (a) negative ion production rate, (b) magnetic field profile, and (c) negative ion temperature on the potential profile has been investigated. A potential peak appears near the wall when the negative ion temperature and density are sufficiently high. Also, the presence of negative ions further decreases the potential in the plasma region for a finite Debye Length (?{sub D})

  17. Refraction-Enhanced X-ray Radiography for Inertial Confinement Fusion and Laser-Produced Plasma Applications

    SciTech Connect

    Koch, J A; Landen, O L; Kozioziemski, B J; Izumi, N; Dewald, E L; Salmonson, J D; Hammel, B A

    2008-08-26

    We explore various laser-produced plasma and inertial-confinement fusion (ICF) applications of phase-contrast x-ray radiography, and we show how the main features of these enhancements can be considered from a geometrical optics perspective as refraction enhancements. This perspective simplifies the analysis, and often permits simple analytical formulae to be derived that predict the enhancements. We explore a raytrace approach to various material interface applications, and we explore a more general example of refractive bending of x-rays by an implosion plasma. We find that refraction-enhanced x-ray radiography of implosions may provide a means to quantify density differences across shock fronts as well as density variations caused by local heating due to high-Z dopants. We also point out that refractive bending by implosions plasmas can blur fine radiograph features, and can also provide misleading contrast information in area-backlit pinhole imaging experiments unless its effects are taken into consideration.

  18. Advanced properties of extended laser-produced plasmas for efficient generation of the high-order harmonics of ultrashort laser pulses

    NASA Astrophysics Data System (ADS)

    Ganeev, R. A.

    2015-04-01

    The review of the studies showing the advanced properties of extended plasma plumes (5 mm) for efficient high-order harmonic generation of laser radiation compared with the short lengths of plasmas (~0.3-0.5 mm) used in previous studies is presented. The harmonic conversion efficiency quadratically increased with the growth of plasma length at the optimal conditions of plasma formation. The studies of this process using the long plasma jets produced on various metal surfaces, particularly including the resonance-enhanced harmonic generation, two-color pump, and extended nanoparticle plasma, are discussed.

  19. Rayleigh-Taylor-Induced electromagnetic fields in laser-produced plasmas

    E-print Network

    Manuel, Mario John-Errol

    2013-01-01

    Spontaneous electromagnetic fields can be important to the dynamic evolution of a plasma by directing heat flow as well as providing additional pressures on the conducting fluids through the Lorentz force. Electromagnetic ...

  20. Application of x-ray-laser interferometry to study high-density laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Wan, A. S.; da Silva, L. B.; Barbee, T. W., Jr.; Cauble, R.; Celliers, P.; Libby, S. B.; London, R. A.; Moreno, J. C.; Trebes, J. E.; Weber, F.

    1996-02-01

    Collisionally pumped soft-x-ray lasers now operate over a wavelength range extending from 4 to 40 nm. With the recent advances in the development of multilayer mirrors and beam splitters in the soft-x-ray regime, we can utilize the unique properties of x-ray lasers to study large, rapidly evolving laser-driven plasmas with high electron densities. Using a neonlike yttrium x-ray laser, which operates at a wavelength of 15.5 nm, we have performed a series of radiography, moire deflectometry, and interferometry experiments to characterize plasmas relevant to inertial confinement fusion. We describe experiments using a soft-x-ray laser interferometer, operated in the Mach-Zehnder configuration, to study CH plasmas. The two-dimensional density profiles obtained from the interferograms allow us to validate and benchmark our numerical models used to study the physics of laser-plasma interactions.

  1. Charge-exchange collisions in interpenetrating laser-produced magnesium plasmas

    E-print Network

    Harilal, S. S.

    intensities. Theoretical calculations also give a large cross section as high as 10 15 cm2 for these charge a supernova explosion ejects plasma into the interstellar medium, and barium is released into the solar wind

  2. Observation of Megagauss-Field Topology Changes due to Magnetic Reconnection in Laser-Produced Plasmas

    E-print Network

    - resolved field measurements are a necessity [7,8], and experiments involving strongly coupled, warm dense,10,1315]. The laser heats the material, forming an expanding, hemispherical plasma bubble with an intense, toroidal B

  3. Small-scale plasma irregularities produced during electron attachment chemical releases

    NASA Technical Reports Server (NTRS)

    Scales, W. A.; Bernhardt, P. A.; Ganguli, G.; Siefring, C. L.; Rodriguez, P.

    1994-01-01

    In situ measurements of small-scale plasma density irregularities made during sounding rocket experiments that released electron attachment materials into the ionosphere are presented. A 2D electrostatic simulation model that includes attachment chemistry is used to study the source and evolution of these irregularities. The simulation shows (1) that large electron flow velocity shears develop on the boundary of the electron depletion and (2) these shears drive a plasma instability that is the likely source of the irregularities.

  4. Propagation velocities of laser-produced plasmas from copper wire targets and water droplets

    NASA Technical Reports Server (NTRS)

    Song, Kyo-Dong; Alexander, Dennis R.

    1994-01-01

    Experiments were performed to determine the plasma propagation velocities resulting from KrF laser irradiation of copper wire target (75 microns diameter) and water droplets (75 microns diameter) at irradiance levels ranging from 25 to 150 GW/sq cm. Plasma propagation velocities were measured using a streak camera system oriented orthogonally to the high-energy laser propagation axis. Plasma velocities were studied as a function of position in the focused beam. Results show that both the shape of the plasma formation and material removal from the copper wire are different and depend on whether the targets are focused or slightly defocused (approximately = 0.5 mm movement in the beam axis). Plasma formation and its position relative to the target is an important factor in determining the practical focal point during high-energy laser interaction with materials. At irradiance of 100 GW/sq cm, the air plasma has two weak-velocity components which propagate toward and away from the incident laser while a strong-velocity component propagates away from the laser beam as a detonation wave. Comparison of the measured breakdown velocities (in the range of 2.22-2.27 x 10(exp 5) m/s) for air and the value calculated by the nonlinear breakdown wave theory at irradiance of 100 GW/sq cm showed a quantitative agreement within approximately 50% while the linear theory and Gaussian pulse theory failed. The detonation wave velocities of plasma generated from water droplets and copper wire targets for different focused cases were measured and analyzed theoretically. The propagation velocities of laser-induced plasma liquid droplets obtained by previous research are compared with current work.

  5. Experimental studies of stimulated Raman scattering in reactor-size, laser-produced plasmas

    Microsoft Academic Search

    C. B. Darrow; R. P. Drake; D. S. Montgomery; P. E. Young; Kent Estabrook; W. L. Kruer; T. W. Johnston

    1991-01-01

    In this paper the results of experiments designed to provide information regarding the scaling of the stimulated Raman scattering (SRS) instability in long-scale-length, inertial- confinement-fusion-reactor-size plasmas are described. Reactor-scale plasma conditions were experimentally simulated by exploding thin CH foils with nine beams of the Nova laser [Rev. Sci. Instrum. 57, 2101 (1986)]. Using a one-dimensional hydro model, the target and

  6. Experimental studies of stimulated Raman scattering in reactor-size, laser-produced plasmas

    Microsoft Academic Search

    C. B. Darrow; R. P. Drake; D. S. Montgomery; P. E. Young; Kent Estabrook; W. L. Kruer; T. W. Johnston

    1991-01-01

    In this paper the results of experiments designed to provide information regarding the scaling of the stimulated Raman scattering (SRS) instability in long-scale-length, inertial- confinement-fusion-reactor-size plasmas are described. Reactor-scale plasma conditions were experimentally simulated by exploding thin CH foils with nine beams of the Nova laser (Rev. Sci. Instrum. {bold 57}, 2101 (1986)). Using a one-dimensional hydro model, the target

  7. Experimental study of the excitation of rhodium isomer in a plasma produced by a picosecond laser pulse

    SciTech Connect

    Afonin, V. I.; Kakshin, A. G.; Mazunin, A. V. [Russian Federal Nuclear Center, Zababakhin All-Russia Research Institute of Technical Physics (Russian Federation)

    2010-03-15

    Estimates and first experimental results on the excitation of a long-lived isomer state (E{sub m} = 39.756 keV, J{sup p} = 9/2{sup -}, and T{sub 1/2} = 56.114 min) of Rh{sup 103} nuclei under the action of X radiation in a hot solid-state-density rhodium plasma produced by a picosecond laser pulse in the SOKOL-P laser facility are presented.

  8. Measurement of Laser Plasma Instability (LPI) Driven Light Scattering from Plasmas Produced by Nike KrF Laser

    NASA Astrophysics Data System (ADS)

    Oh, Jaechul; Weaver, J. L.; Phillips, L.; Obenschain, S. P.; Schmitt, A. J.; Kehne, D. M.; Serlin, V.; Lehmberg, R. H.; McLean, E. A.; Manka, C. K.

    2010-11-01

    With short wavelength (248 nm), large bandwidth (13 THz), and ISI beam smoothing, Nike KrF laser provides unique research opportunities and potential for direct-drive inertial confinement fusion. Previous Nike experiments observed two plasmon decay (TPD) driven signals from CH plasmas at the laser intensities above 2x10^15 W/cm^2 with total laser energies up to 1 kJ of 350 ps FWHM pulses. We have performed a further experiment with longer laser pulses (0.54.0 ns FWHM) and will present combined results of the experiments focusing on light emission data in spectral ranges relevant to the Raman (SRS) and TPD instabilities. Time- or space-resolved spectral features of TPD were detected at different viewing angles and the absolute intensity calibrated spectra of thermal background were used to obtain blackbody temperatures in the plasma corona. The wave vector distribution in k-space of the participating TPD plasmons will be also discussed. These results show promise for the proposed direct-drive designs.

  9. Emission study of alumina plasma produced by a KrF laser

    NASA Astrophysics Data System (ADS)

    Yahiaoui, K.; Abdelli-Messaci, S.; Messaoud-Aberkane, S.; Kerdja, T.; Kellou, H.

    We report on the plasma emission formed from an ?-alumina target when irradiated by laser into vacuum and through oxygen gas. Two diagnostic tools have been used: ICCD camera fast imaging and optical emission spectroscopy. The alumina plasma was induced by a KrF laser beam at a wavelength of 248 nm and pulse duration of 25 ns. The laser fluence was set to 8 J/cm2 and the oxygen pressure was varied from 0.01 to 5 mbar. By using the ICCD camera, two dimensional images of the plasma expansion were taken at different times. Depending on oxygen pressure and time delay, the expansion behavior of the plasma showed free expansion, plume splitting, shock wave formation, hydrodynamic instability and deceleration of the plume. Using optical emission spectroscopy, the plasma emission revealed the presence of neutral Al I, Al II, Al III into vacuum and under oxygen ambiance. The molecular emission of aluminum oxide (AlO) was detected only in oxygen ambiance. It should be noted that no oxygen lines were observed. Finally, the evolution of the electronic temperature along the normal axis from the target surface, into vacuum, was estimated using the Boltzmann plot method.

  10. High density collimated beams of relativistic ions produced by petawatt laser pulses in plasmas

    PubMed

    Sentoku; Liseikina; Esirkepov; Califano; Naumova; Ueshima; Vshivkov; Kato; Mima; Nishihara; Pegoraro; Bulanov

    2000-11-01

    Under optimal interaction conditions ions can be accelerated up to relativistic energies by a petawatt laser pulse in both underdense and overdense plasmas. Two-dimensional particle in cell simulations show that the laser pulse drills a channel through an underdense plasma slab due to relativistic self-focusing. Both ions and electrons are accelerated in the head region of the channel. However, ion acceleration is more effective at the end of the slab. Here electrons from the channel expand in vacuum and are followed by the ions dragged by the Coulomb force arising from charge separation. A similar mechanism of ion acceleration occurs when a superintense laser pulse interacts with a thin slab of overdense plasma and the pulse ponderomotive pressure moves all the electrons away from a finite-diameter spot. PMID:11102086

  11. A Black-box Modelling Engine for Discharge Produced Plasma Radiation Sources

    NASA Astrophysics Data System (ADS)

    Zakharov, S. V.; Choi, P.; Krukovskiy, A. Y.; Novikov, V. G.; Zakharov, V. S.; Zhang, Q.

    2006-01-01

    A Blackbox Modelling Engine (BME), is an instrument based on the adaptation of the RMHD code Z*, integrated into a specific computation environment to provide a turn key simulation instrument and to enable routine plasma modelling without specialist knowledge in numerical computation. Two different operating modes are provided: Detailed Physics mode & Fast Numerics mode. In the Detailed Physics mode, non-stationary, non-equilibrium radiation physics have been introduced to allow the modelling of transient plasmas in experimental geometry. In the Fast Numerics mode, the system architecture and the radiation transport is simplified to significantly accelerate the computation rate. The Fast Numerics mode allows the BME to be used realistically in parametric scanning to explore complex physical set up, before using the Detailed Physics mode. As an example of the results from the BME modelling, the EUV source plasma dynamics in the pulsed capillary discharge are presented.

  12. Injection and acceleration of electron bunch in a plasma wakefield produced by a chirped laser pulse

    SciTech Connect

    Afhami, Saeedeh; Eslami, Esmaeil, E-mail: eeslami@iust.ac.ir [Department of Physics, Iran University of Science and Technology (IUST), Narmak, Tehran 16846-13114 (Iran, Islamic Republic of)

    2014-06-15

    An ultrashort laser pulse propagating in plasma can excite a nonlinear plasma wakefield which can trap and accelerate charged particles up to GeV. One-dimensional analysis of electron injection, trapping, and acceleration by different chirped pulses propagating in plasma is investigated numerically. In this paper, we inject electron bunches in front of the chirped pulses. It is indicated that periodical chirped laser pulse can trap electrons earlier than other pulses. It is shown that periodical chirped laser pulses lead to decrease the minimum momentum necessary to trap the electrons. This is due to the fact that periodical chirped laser pulses are globally much efficient than nonchirped pulses in the wakefield generation. It is found that chirped laser pulses could lead to much larger electron energy than that of nonchirped pulses. Relative energy spread has a lower value in the case of periodical chirped laser pulses.

  13. Infrared nanosecond laser-metal ablation in atmosphere: Initial plasma during laser pulse and further expansion

    SciTech Connect

    Wu, Jian; Wei, Wenfu; Li, Xingwen; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)] [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)

    2013-04-22

    We have investigated the dynamics of the nanosecond laser ablated plasma within and after the laser pulse irradiation using fast photography. A 1064 nm, 15 ns laser beam was focused onto a target made from various materials with an energy density in the order of J/mm{sup 2} in atmosphere. The plasma dynamics during the nanosecond laser pulse were observed, which could be divided into three stages: fast expansion, division into the primary plasma and the front plasma, and stagnation. After the laser terminated, a critical moment when the primary plasma expansion transited from the shock model to the drag model was resolved, and this phenomenon could be understood in terms of interactions between the primary and the front plasmas.

  14. High-resolution imaging spectrometer for recording absolutely calibrated far ultraviolet spectra from laser-produced plasmas.

    PubMed

    Brown, Charles M; Seely, John F; Feldman, Uri; Holland, Glenn E; Weaver, James L; Obenschain, Steven P; Kjornrattanawanich, Benjawan; Fielding, Drew

    2008-10-01

    An imaging spectrometer was designed and fabricated for recording far ultraviolet spectra from laser-produced plasmas with wavelengths as short as 155 nm. The spectrometer implements a Cassegrain telescope and two gratings in a tandem Wadsworth optical configuration that provides diffraction limited resolution. Spectral images were recorded from plasmas produced by the irradiation of various target materials by intense KrF laser radiation with 248 nm wavelength. Two pairs of high-resolution gratings can be selected for the coverage of two wavebands, one grating pair with 1800 grooves/mm and covering approximately 155-175 nm and another grating pair with 1200 grooves/mm covering 230-260 nm. The latter waveband includes the 248 nm KrF laser wavelength, and the former waveband includes the wavelength of the two-plasmon decay instability at 23 the KrF laser wavelength (165 nm). The detection media consist of a complementary metal oxide semiconductor imager, photostimulable phosphor image plates, and a linear array of 1 mm(2) square silicon photodiodes with 0.4 ns rise time. The telescope mirrors, spectrometer gratings, and 1 mm(2) photodiode were calibrated using synchrotron radiation, and this enables the measurement of the absolute emission from the laser-produced plasmas with temporal, spatial, and spectral resolutions. The spectrometer is capable of measuring absolute spectral emissions at 165 nm wavelength as small as 5x10(-7) J/nm from a plasma source area of 0.37 mm(2) and with 0.4 ns time resolution. PMID:19044704

  15. High-resolution imaging spectrometer for recording absolutely calibrated far ultraviolet spectra from laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Brown, Charles M.; Seely, John F.; Feldman, Uri; Holland, Glenn E.; Weaver, James L.; Obenschain, Steven P.; Kjornrattanawanich, Benjawan; Fielding, Drew

    2008-10-01

    An imaging spectrometer was designed and fabricated for recording far ultraviolet spectra from laser-produced plasmas with wavelengths as short as 155 nm. The spectrometer implements a Cassegrain telescope and two gratings in a tandem Wadsworth optical configuration that provides diffraction limited resolution. Spectral images were recorded from plasmas produced by the irradiation of various target materials by intense KrF laser radiation with 248 nm wavelength. Two pairs of high-resolution gratings can be selected for the coverage of two wavebands, one grating pair with 1800 grooves/mm and covering approximately 155-175 nm and another grating pair with 1200 grooves/mm covering 230-260 nm. The latter waveband includes the 248 nm KrF laser wavelength, and the former waveband includes the wavelength of the two-plasmon decay instability at 23 the KrF laser wavelength (165 nm). The detection media consist of a complementary metal oxide semiconductor imager, photostimulable phosphor image plates, and a linear array of 1 mm2 square silicon photodiodes with 0.4 ns rise time. The telescope mirrors, spectrometer gratings, and 1 mm2 photodiode were calibrated using synchrotron radiation, and this enables the measurement of the absolute emission from the laser-produced plasmas with temporal, spatial, and spectral resolutions. The spectrometer is capable of measuring absolute spectral emissions at 165 nm wavelength as small as 510-7 J/nm from a plasma source area of 0.37 mm2 and with 0.4 ns time resolution.

  16. Late-time particle emission from laser-produced graphite plasma S. S. Harilal,a)

    E-print Network

    Harilal, S. S.

    Nd: yttrium aluminum garnet (YAG) laser in vacuum. The time evolution of graphite plasma material properties and explained due to material spallation caused by overheat- ing the trapped gases through thermal diffusion along the layer structures of graphite. VC 2011 American Institute of Physics

  17. Diagnostics and analyses of decay process in laser produced tetrakis,,dimethyl-amino...ethylene plasma

    E-print Network

    Scharer, John E.

    , electron temperature effects, or multi-ion species processes. On the other hand, a new decay mechanism ) and low electron temperature 0.1 eV . To investigate the plasma decay processes, a fast Langmuir probe5 This technique has many potential applications, including a microwave reflector or absorber.4

  18. Soft X-ray spectrum of laser-produced aluminum plasma

    NASA Astrophysics Data System (ADS)

    Vergunova, G. A.; Grushin, A. S.; Kologrivov, A. A.; Novikov, V. G.; Osipov, M. V.; Puzyrev, V. N.; Rozanov, V. B.; Starodub, A. N.; Yakushev, O. F.

    2015-05-01

    Soft X-ray spectra (30-70 ) of aluminum plasma have been measured in experiments carried out at the Kanal-2 laser facility at laser intensities of (1-7) 1013 W/cm2. It is shown that the measured spectra satisfactory agree with those calculated using the RADIAN numerical code.

  19. Nonlinear effects produced by continuous electromagnetic waves propagating in weakly dissipative plasmas

    Microsoft Academic Search

    Raymond Jancel

    1978-01-01

    A general perturbation method, founded on the multiple-space-scales technique, is applied to the kinetic analysis of the nonlinear effects generated by continuous transverse electromagnetic waves of finite amplitude propagating in warm and partially ionized plasmas. The collisional and weakly collisional cases are successively studied for a typical ordering of the significant parameters. In each case, it is first shown that

  20. A comparison of kinetic and multifluid simulations of laser-produced colliding plasmas

    SciTech Connect

    Rambo, P.W.; Procassini, R.J.

    1994-09-01

    The collision and subsequent interaction of counter-streaming plasmas occurs in several areas of laser-plasma research including double foil targets for x-ray lasers and the plasma blow-off inside ICF hohlraums. Because a single fluid model allows for only one value of the flow velocity at any one spatial location, interpenetration of the plamas is not allowed resulting in immediate stagnation with complete conversion of the ion-streaming kinetic energy to thermal energy. Multifluid models have been developed which employ multiple ion fluid species that interact through the self-consistent electrostatic field and collisional coupling. Because they are approximations to a kinetic situation, the form of these coupling coefficients is not unique, with various workers using differing approximations. More recently, Larroche has implemented a finite difference approach to the ion Fokker-Planck equation while Jones and co-workers have performed two-dimensional simulations of colliding plasmas using a particle-in-cell code with a new collisional model. Our kinetic modeling also makes use of particle in cell (PIC) techniques with Monte Carlo (MC) particle-particle collisions algorithm that is equivalent to the Fokker-Planck collision operator. We have made direct comparison of this MC-PIC model to multifluid simulations on both simple slowing-down and equilibration problems as well as problems characteristic of laser generated colliding plasmas. These comparisons have established the validity of the multifluid model as well as aided in the development of the kinetic capability for more challenging geometries.

  1. Dynamics of double-pulse laser produced titanium plasma inferred from thin film morphology and optical emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Krstulovi?, N.; Salamon, K.; Modic, M.; Bi?an, M.; Milat, O.; Miloevi?, S.

    2015-05-01

    In this paper, dynamics of double-pulse laser produced titanium plasma was studied both directly using optical emission spectroscopy (OES) and indirectly from morphological properties of deposited thin films. Both approaches yield consistent results. Ablated material was deposited in a form of thin film on the Si substrate. During deposition, plasma dynamics was monitored using optical emission spectroscopy with spatial and temporal resolutions. The influence of ablation mode (single and double) and delay time ? (delay between first and second pulses in double-pulse mode) on plasma dynamics and consequently on morphology of deposited Ti-films was studied using X-ray reflectivity and atomic force microscopy. Delay time ? was varied from 170 ns to 4 ?s. The results show strong dependence of both emission signal and Ti-film properties, such as thickness, density and roughness, on ?. In addition, correlation of average density and thickness of film is observed. These results are discussed in terms of dependency of angular distribution and kinetic energy of plasma plume particles on ?. Advantages of using double-pulse laser deposition for possible application in thin film production are shown.

  2. Numerical simulation of the coal combustion process initiated by a plasma source

    NASA Astrophysics Data System (ADS)

    Askarova, A. S.; Messerle, V. E.; Ustimenko, A. B.; Bolegenova, S. A.; Maksimov, V. Yu.

    2014-12-01

    Numerical experiments on the torch combustion of the coal dust prepared by a plasma-thermochemical treatment for combustion have been done using the method of three-dimensional simulation. It is shown that the plasma preparation of coal for combustion enables one to optimize the process, improve the conditions for inflammation and combustion and minimize the emissions of harmful substances.

  3. Dense and strong plasma initiated by Ca0.7Sr0.3TiO3 ceramic

    NASA Astrophysics Data System (ADS)

    Li, Ruixing; Tang, Qing; Yin, Shu; Yamaguchi, Yukishige; Sato, Tsugio

    2004-08-01

    In order to find a kind of material that is able to initiate plasma avalanches, Ca0.7Sr0.3TiO3 ceramic, which possesses high permittivity, was prepared by liquid phase sintering and used as a dielectric barrier to decompose CO2 in order to investigate the efficiency and characteristics of this ceramic. The results were compared with commercial alumina and silica glass, which possess lower permittivities, but however, were widely used in previous studies. The mechanical and dielectric properties of Ca0.7Sr0.3TiO3 were greatly enhanced by adding 0.5 wt. % Li2Si2O5 as a sintering additive. Although Ca0.7Sr0.3TiO3 without an additive was fractured before the arcing plasma, that which was sintered with 0.5 wt. % Li2Si2O5 successfully generated a dielectric barrier discharge (DBD) plasma and the CO2 conversion was much higher than with those using an alumina or silica glass barrier. The plasma behaviors of using different dielectric materials were studied during the processes of the DBD plasma burst. It was found that the density and strength of current pulses increased with increasing permittivity, and as a consequence, very dense and strong current pulses were initiated by this Ca0.7Sr0.3TiO3 with 0.5 wt. % Li2Si2O5 ceramic because of its high permittivity; likewise, they were efficient in reducing CO2. The density and strength of current pulses are also found to be the dominative parameters of the plasma reaction. This Ca0.7Sr0.3TiO3 ceramic was sintered using Li2Si2O5 as a sintering additive and used as a dielectric barrier of DBD for the first time.

  4. Dense and strong plasma initiated by Ca0.7Sr0.3TiO3 ceramic

    Microsoft Academic Search

    Ruixing Li; Qing Tang; Shu Yin; Yukishige Yamaguchi; Tsugio Sato

    2004-01-01

    In order to find a kind of material that is able to initiate plasma avalanches, Ca0.7Sr0.3TiO3 ceramic, which possesses high permittivity, was prepared by liquid phase sintering and used as a dielectric barrier to decompose CO2 in order to investigate the efficiency and characteristics of this ceramic. The results were compared with commercial alumina and silica glass, which possess lower

  5. Demonstration of an optical mixing technique to drive Kinetic Electrostatic Electron Nonlinear waves in laser produced plasmas

    E-print Network

    Kline, J L; Bertsche, W A; Kurnit, N A; Montgomery, D S; Johnson, R P; Niemann, C

    2012-01-01

    A nitrogen gas Raman cell system has been constructed to shift a 70 J 527 nm laser beam to 600 nm with 20 J of energy. The 600 nm probe and a 200J, 527 nm pump beam were optically mixed in a laser produced (gas jet) plasma. The beating of the two laser beams formed a ponderomotive force that can drive Kinetic Electrostatic Electron Nonlinear (KEEN) waves discovered in Vlasov-Poisson simulations by Afeyan et al [1,2]. KEEN waves were detected in these experiments where traditional plasma theory would declare there to be a spectral gap (ie no linear waves possible). The detection was done using Thomson scattering with probe wavelengths of both 351 nm and 263.5 nm.

  6. Characteristics of sheath-driven tangential flow produced by a low-current DC surface glow discharge plasma actuator

    NASA Astrophysics Data System (ADS)

    Shin, Jichul; Shajid Rahman, Mohammad

    2014-08-01

    An experimental investigation of low-speed flow actuation at near-atmospheric pressure is presented. The flow actuation is achieved via low-current ( \\lesssim 1.0 mA) continuous or pulsed DC surface glow discharge plasma. The plasma actuator, consisting of two sharp-edged nickel electrodes, produces a tangential flow in a direction from anode to cathode, and is visualized using high-speed schlieren photography. The induced flow velocity estimated via the schlieren images reaches up to 5 m/s in test cases. The actuation capability increases with pressure and electrode gap distances, and the induced flow velocity increases logarithmically with the discharge power. Pulsed DC exhibits slightly improved actuation capability with better directionality. An analytic estimation of induced flow velocity obtained based on ion momentum in the cathode sheath and gas dynamics in one-dimensional flow yields values similar to those measured.

  7. Tritium containment in the dust and debris of plasma-facing materials produced during operations

    SciTech Connect

    Konkashbaev, I.; Grebenshikov, J. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Hassanein, A. [Argonne National Lab., IL (United States)

    1996-09-01

    Tritium behavior in plasma-facing components of future tokamak reactors such as ITER is an essential factor in evaluating and choosing a successful candidate for a plasma-facing material (PFM). One important parameter that influence tritium build-up and release in the Generated dust of PFMs is the effect of material porosity on tritium behavior. Diffusion in porous materials, for example, consists of three different diffusion processes: along grain boundaries, along micro-crystallites, and diffusion in pure structure crystallites. A model is developed to evaluate and assess the sensitivity of tritium accumulation and permeation of candidate materials due to porosity. Specific laboratory experiments relevant to reactor conditions, in currently existing and available facilities, are required to help in selecting the best candidate material.

  8. Expansion dynamics of ultrafast laser produced plasmas in the presence of ambient argon

    NASA Astrophysics Data System (ADS)

    Diwakar, P. K.; Harilal, S. S.; Hassanein, A.; Phillips, M. C.

    2014-10-01

    We investigated the expansion dynamics of fs laser ablated brass plasma in Ar at various pressure levels ranging from 10-5 Torr to atmospheric conditions using time-resolved and spectrally resolved two-dimensional imaging. Significant changes in plume morphology were noticed at varying pressure levels which included free expansion, spherical to cylindrical geometry changes, sharpening, and confinement. The temporal evolution of excited Cu and Zn species in the plume were imaged using narrow band-pass interference filters, and their hydrodynamic expansion features were compared. 2D imaging coupled with monochromatic line selection showed velocity differences, uneven distribution, and aspect ratio differences among the plume species. Plume morphological changes were found to be significant at intermediate pressure levels (10 Torr) where plasma emissivity was found to be maximum. The expansion features of plume were compared with various models and found to be generally in good agreement.

  9. Analysis of two colliding laser-produced plasmas by emission spectroscopy and fast photography

    Microsoft Academic Search

    C. Snchez-Ak; D. Mustri-Trejo; T. Garca-Fernndez; M. Villagrn-Muniz

    2010-01-01

    In this work two colliding laser-induced plasmas (LIP) on Cu and C were studied by means of time resolved emission spectroscopy and fast photography. The experiments were performed using two opposing parallel targets of Cu and C in vacuum, ablated with two synchronized ns lasers. The results showed an increased emission intensity from copper ions Cu II (368.65, 490.97, 493.16,

  10. Experiments on radiative collapse in laser-produced plasmas relevant to astrophysical jets

    Microsoft Academic Search

    K. Shigemori; R. Kodama; D. R. Farley; T. Koase; K. G. Estabrook; B. A. Remington; D. D. Ryutov; Y. Ochi; H. Azechi; J. Stone; N. Turner

    2000-01-01

    We report a laser experiment of astrophysical interest on radiative jet formation. Conically shaped targets are irradiated by intense laser light. An ablated plasma flow collides at the axis of the cone targets, then propagates at high Mach number, forming a jetlike structure. We measure time-resolved x-ray self-emission images from the jets. The diameter of the jet increases with decreasing

  11. K-shell emission from 140 femtosecond laser-produced plasmas created from porous aluminum targets

    SciTech Connect

    Shepherd, R.; Price, D.; White, B.; Osterheld, A.; Walling, R.; Slaughter, D.; Stewart, R. [Lawrence Livermore National Lab., CA (United States); Gordan, S. [California Univ., Berkeley, CA (United States). Dept. of Physics

    1992-06-05

    The K-shell emission from flat and porous aluminum targets is used to infer the efficiency of creating a high temperature (>100eV), thermal plasma with 800 nm, 140 fs laser light. The K-shell emission from flat aluminum targets is fond to be significantly less than that of the porous targets, implying a lower temperature and less efficient coupling between the target and ultra-short pulse laser light.

  12. Amorphous silicon for photovoltaics produced by new microwave plasma-deposition techniques

    NASA Astrophysics Data System (ADS)

    Paquin, L.; Masson, D.; Wertheimer, M. R.; Moisan, M.

    1985-06-01

    Amorphous hydrogenated silicon (a-Si:H) has been prepared by microwave (2.45 GHz) plasmas in Ar-SiH4 mixtures using two different deposition systems, a large-volume microwave plasma (LMP) apparatus, and a Surfatron system. Films of a-Si:H are characterized structurally (primarily by scanning electron microscopy), and by Fourier transform IR spectroscopy, as well as according to their electrooptical properties (dark and photoconductivity, I-V characteristics of Schottky-barrier diodes). Although microwave plasmas are thought to differ significantly from conventional lower frequency plasmas, results of the present characterizations show no evidence of this. Deposition in the Surfatron system gives rise to device-grade a-Si:H, as demonstrated by Schottky cell efficiencies exceeding 3 percent. It has not been possible to duplicate this in the LMP system in spite of nominally identical fabrication conditions; these films have gross columnar morphology, and they react with atmospheric constituents to give a-Si:(H, C, O) alloys. More pronounced ion bombardment of the substrate during deposition is thought to account for the better quality of Surfatron films. Finally an aging effect of Au/a-Si:H/Sb-Cr Schottky diodes is described, unlike any reported hitherto; in a typical device, conversion efficiency was observed to rise by roughly 60 percent after about two months, then it decreased slowly. Preliminary investigations of this effect using various surface analytical techniques suggest that Au acts as a catalyst for room-temperature chemical reactions between a-Si:H and atmospheric constituents, primarily oxygen and water vapor.

  13. Effect of N doping on structure and properties of DLC films produced by plasma beam deposition

    Microsoft Academic Search

    Bing K. Yen; Jan-Ulrich Thiele; Michael Geisler; Paul H. Kasai; Richard L. White; Brian R. York; Henrik Zadoori; Andrew J. Kellock; Wade C. Tang; Tsai-Wei Wu; Michael F. Toney; Bruno Marchon

    2001-01-01

    A novel plasma beam source for the deposition of DLC films is described. Wide ranges of ion energy (130-250 eV) and C2H2\\/N2 flow conditions have been used to investigate the effect of N doping an the structure and properties of DLC films. The resulting films are characterized by their chemical composition, Raman spectra, electron spin density, mass density, and hardness,

  14. Molecular ion formation in decaying plasmas produced in pure argon and krypton

    Microsoft Academic Search

    M. Langenwalter; H. Helm

    1981-01-01

    The formation of molecular ions Ar2+ and Kr2+ in decaying plasmas of the respective rare gases is studied at pressures between 0.2 and 3 Torr at room temperature. Measurements of the decay of He2+ in He are made to test the experimental technique used. The reaction rate coefficient for the process Ar+(2P3\\/2)+2 Ar?Ar2++Ar is found to be (2.350.2)10?31 cm6 s?1.

  15. Electron transport phenomena and dense plasmas produced by ultra-short pulse laser interaction

    SciTech Connect

    More, R.M.

    1994-07-08

    Recent experiments with femtosecond lasers provide a test bed for theoretical ideas about electron processes in hot dense plasmas. We briefly review aspects of electron conduction theory likely to prove relevant to femtosecond laser absorption. We show that the Mott-Ioffe-Regel limit implies a maximum inverse bremsstrahlung absorption of about 50% at temperatures near the Fermi temperature. We also propose that sheath inverse bremsstrahlung leads to a minimum absorption of 7-10% at high laser intensity.

  16. Measurement of Neutrons Produced by Beam-Target Interactions via a Coaxial Plasma Accelerator

    NASA Astrophysics Data System (ADS)

    Cauble, Scott; Poehlmann, Flavio; Rieker, Gregory; Cappelli, Mark

    2011-10-01

    This poster presents a method to measure neutron yield from a coaxial plasma accelerator. Stored electrical energies between 1 and 19 kJ are discharged within a few microseconds across the electrodes of the coaxial gun, accelerating deuterium gas samples to plasma beam energies well beyond the keV energy range. The focus of this study is to examine the interaction of the plasma beam with a deuterated target by designing and fabricating a detector to measure neutron yield. Given the strong electromagnetic pulse associated with our accelerator, indirect measurement of neutrons via threshold-dependent nuclear activation serves as both a reliable and definitive indicator of high-energy particles for our application. Upon bombardment with neutrons, discs or stacks of metal foils placed near the deuterated target undergo nuclear activation reactions, yielding gamma-emitting isotopes whose decay is measured by a scintillation detector system. By collecting gamma ray spectra over time and considering nuclear cross sections, the magnitude of the original neutron pulse is inferred.

  17. Expansion Dynamics of Ultrafast Laser Produced Plasmas in the Presence of Ambient Argon

    SciTech Connect

    Diwakar, P. K.; Harilal, Sivanandan S.; Hassanein, A.; Phillips, Mark C.

    2014-10-07

    In this paper, we report the emission features of fs laser ablated brass plasma plumes at various Ar background pressure levels ranging from vacuum to atmospheric conditions. Spectrally integrated 2D-imaging of plasma self-emission showed several interesting features at various pressure levels which consists of plume morphological changes, increase in persistence, confinement, and internal structures. Spatially resolved wavelength dispersed images of the plume were recorded for characterizing the spectral features at various pressure levels and also used for obtaining spatial distribution of Cu I and Zn I species in the plume, signal to noise ratios and fundamental parameters of the plasma; viz. temperature and density. The spatial evolution of excitation temperature and density showed significant changes at various ambient pressure levels and these results were correlated to morphological changes seen in the plume images. Optimum signal to background ratios for emission lines were observed in the moderate pressure range (~ 1-10 Torr). Optical time-of-flight profiles were used to study time evolution of various species in the plume and noticed oscillations at intermediate pressure levels. Possible mechanisms for observed changes in plume shape, optical emission intensity, and dual peak structures in time-of-flight profiles were discussed.

  18. Improved protocol for measurement of plasma ?-amyloid in longitudinal evaluation of Alzheimer's Disease Neuroimaging Initiative study patients

    PubMed Central

    Figurski, Michal J.; Waligrska, Teresa; Toledo, Jon; Vanderstichele, Hugo; Korecka, Magdalena; Lee, Virginia M. Y.; Trojanowski, John Q.; Shaw, Leslie M.

    2013-01-01

    Background The interassay variability and inconsistency of plasma ?-amyloid (A?) measurements among centers are major factors precluding the interpretation of results and a substantial obstacle in the meta-analysis across studies of this biomarker. The goal of this investigation was to address these problems by improving the performance of the bioanalytical method. Methods We used the Luminex immunoassay platform with a multiplex microsphere-based reagent kit from Innogenetics. A robotic pipetting system was used to perform crucial steps of the procedure. The performance of this method was evaluated using two kit control samples and two quality control plasma samples from volunteer donors, and by retesting previously assayed patient samples in each run. This setup was applied to process 2454 patient plasma samples from the Alzheimer's Disease Neuroimaging Initiative study biofluid repository. We have additionally evaluated the correlations between our results and cerebrospinal fluid (CSF) biomarker data using mixed-effects modeling. Results The average precision values of the kit controls were 8.3% for A?1-40 and 4.0% for A?1-42, whereas the values for the plasma quality controls were 6.4% for A?1-40 and 4.8% for A?1-42. From the testretest evaluation, the average precision was 7.2% for A?1-40 and 4.5% for A?1-42. The range of final plasma results for Alzheimer's Disease Neuroimaging Initiative patients was 13 to 372 pg/mL (median: 164 pg/mL) for A?1-40 and 3.5 to 103 pg/mL (median: 39.3 pg/mL) for A?1-42. We found that sample collection parameters (blood volume and time to freeze) have a small, but significant, influence on the result. No significant difference was found between plasma A? levels for patients with Alzheimer's disease and healthy control subjects. We have determined multiple significant correlations of plasma A?1-42 levels with CSF biomarkers. The relatively strongest, although modest, correlation was found between plasma A?1-42 levels and CSF p-tau181/A?1-42 ratio in patients with mild cognitive impairment. Plasma A?1-40 correlations with CSF biomarkers were weaker and diminished completely when we used longitudinal data. No significant correlations were found for the plasma A?1-42/A?1-40 ratio. Conclusions The precision of our robotized method represents a substantial improvement over results reported in the literature. Multiple significant correlations between plasma and CSF biomarkers were found. Although these correlations are not strong enough to support the use of plasma A? measurement as a diagnostic screening test, plasma A?1-42 levels are well suited for use as a pharmacodynamic marker. PMID:22748936

  19. Processes for forming exoergic structures with the use of a plasma and for producing dense refractory bodies of arbitrary shape therefrom

    DOEpatents

    Holt, J. Birch (San Jose, CA); Kelly, Michael D. (West Alexandria, OH)

    1990-01-01

    Plasma spraying methods of forming exoergic structures and coatings, as well as exoergic structures produced by such methods, are provided. The methods include the plasma spraying of reactive exoergic materials that are capable of sustaining a combustion synthesis reaction onto a flat substrate or into molds of arbitrary shape and igniting said plasma sprayed materials, either under an inert gas pressure or not, to form refractory materials of varying densities and of varying shapes.

  20. Independent determinations of temperature and ionization balance in a laser-produced plasma by use of L-shell x-ray spectra

    SciTech Connect

    Goldstein, W.H.; Walling, R.S.; Bailey, J.; Chen, M.H.; Fortner, R.; Klapisch, M.; Phillips, T.; Stewart, R.E.

    1987-06-01

    We outline a method for determining independently the electron temperature and charge state distribution in plasmas by use of ratios of sodiumlike satellite and neonlike resonance x-ray emission. The technique is applied to a bromine plasma produced by laser irradiation of a microdot. Results are consistent with the formation in the corona of a recombining plasma. The temperature is found to decrease with distance in the corona.

  1. Copper, zinc, tin and lead in canned evaporated milk, produced in Lithuania: the initial content and its change at storage.

    PubMed

    Ramonaityte, D T

    2001-01-01

    The study has been carried out to elucidate what contents of heavy metals were typical for canned milk products--evaporated (TS 25.5-28.5%) sterilized milk and condensed sweetened milk, produced in Lithuania in the period 1983-1997. The influence of storage time upon the level of Sn, Pb, Cu and Zn in the products has also been determined. The results show that the most considerable changes occurred in Cu concentration, which gradually decreased from the maximum level in 1983-1985 (2.23 +/- 0.18 mg/kg) to the minimum level in the latest years (0.44 +/- 0.01 mg/kg). Such variation of copper content in canned milks can be closely connected with its changes in raw milk. Zinc content in canned milk products also was in good agreement with raw milk. The content of tin and lead in the canned products many times exceeded their concentration in raw milk and ranged from 28 +/- 2 and 0.093 +/- 0.005 to 114 +/- 4 and 0.29 +/- 0.01 mg/kg, respectively. It has been determined that the dependence of the concentration of tin and lead on the storage time of concentrated (or evaporated) sterilized milk is nearest to the parabolic, and in sweetened condensed milk to the exponential function, whereas the small increase of copper and zinc concentrations can be described by straight-line function. The functional dependence obtained enables one to predict the Sn and Pb level in canned evaporated milk products after storage and to foresee the safe initial concentration of these metals in freshly produced evaporated milk, assigned for storage. PMID:11212545

  2. Laser-plasma diamagnetism in the presence of an ambient magnetized plasma

    E-print Network

    California at Los Angles, University of

    Laser-plasma diamagnetism in the presence of an ambient magnetized plasma M. VanZeelanda) and W cavity created by a dense laser-produced plasma initially, nlpp /n0 1) expanding into an ambient magnetized background plasma (n0 2 1012 cm 3 ) capable of supporting Alfven waves. The experiments

  3. Observation of dielectronic satellites in the K -spectrum of argon ions in plasma produced by femtosecond laser pulses

    Microsoft Academic Search

    A. I. Magunov; A. Ya. Faenov; I. Yu. Skobelev; T. A. Pikuz; E. Bimont; P. Quinet; F. Blasco; C. Bonte; F. Dorchies; T. Caillaud; F. Salin; C. Stenz

    2002-01-01

    The satellite structure of 1s2p\\u000a 1,3\\u000a P\\u000a 1-1s\\u000a 21\\u000a S\\u000a 0 lines of the He-like argon ion in plasma produced by a 45-fs laser pulse in a gas-jet cluster target is measured with a high\\u000a spectral resolution. Radiation transitions 2p ? 1s from autoionizing states (AISs) are detected for ions ranging from Li-like to F-like. The spectrum observed is theoretically

  4. Initial Operation of the Miniaturized Inductively Heated Plasma Generator IPG6

    NASA Astrophysics Data System (ADS)

    Dropmann, Michael; Herdrich, Georg; Laufer, Rene; Koch, Helmut; Gomringer, Chris; Cook, Mike; Schmoke, Jimmy; Matthews, Lorin; Hyde, Truell

    2012-10-01

    In close collaboration between the Center for Astrophysics, Space Physics and Engineering Research (CASPER) at Baylor University, Texas, and the Institute of Space Systems (IRS) at the University of Stuttgart, Germany, two plasma wind tunnel facilities of similar type have been established using the inductively heated plasma source IPG6 which is based on proven IRS designs. The facility at Baylor University (IPG6-B) works at a frequency of 13.56 MHz and a maximum power of 15 kW. A vacuum pump of 160m^3/h in combination with a butterfly valve allows pressure control in a wide range. First experiments have been conducted with Air, O2 and N2 as working gases and volumetric flow rates of up to 14 L/min at pressures of a few 100 Pa, although pressures below 1 Pa are achievable at lower flow rates. The maximum tested electric power so far was 8 kW. Plasma powers and total pressures in the plasma jet have been obtained. In the near future the set up of additional diagnostics, the use of other gases (i.e. H2, He), and the integration of a dust particle accelerator are planned. The intended fields of research are basic investigation in thermo-chemistry and plasma radiation, space plasma environments and high heat fluxes e.g. in fusion devices or during atmospheric entry of spacecraft.

  5. Molecular ion formation in decaying plasmas produced in pure argon and krypton

    NASA Astrophysics Data System (ADS)

    Grssl, M.; Langenwalter, M.; Helm, H.; Mrk, T. D.

    1981-02-01

    The formation of molecular ions Ar2+ and Kr2+ in decaying plasmas of the respective rare gases is studied at pressures between 0.2 and 3 Torr at room temperature. Measurements of the decay of He2+ in He are made to test the experimental technique used. The reaction rate coefficient for the process Ar+(2P3/2)+2 Ar?Ar2++Ar is found to be (2.350.2)10-31 cm6 s-1. The corresponding reaction rate coefficient in krypton is found to be (2.20.2)10-31 cm6 s-1. Using a recently proposed reaction model [Helm and Varney (1978)] for the excited fine structure state (2P1/2), the pressure dependence of the reaction rate coefficient describing the destruction Ar+(2P1/2)+2Ar?products is calculated. The pressure dependence and magnitude of the coefficient found are in agreement with the experimental findings of Liu and Conway (1975) for the above process. The process could not be studied experimentally in our system due to the low density of Ar+(2P1/2) in our discharge. The low density is inferred indirectly and the process responsible for the fast removal of the excited ion species in the argon plasma is regarded to be the superelastic collision process with slow plasma electrons Ar+(2P1/2)+e?Ar+(2P3/2)+e+0.18 eV for which a rate coefficient ?10-7 cm3 s-1 is estimated. At late times in the afterglow a significant source of ionization is observed in argon. This source is consistent with ionizing collisions of metastable argon atoms. Its importance increased with pressure since the diffusive loss of metastable atoms becomes insignificant as the pressure is raised.

  6. Use of a heavy-current stabilized arc to produce an air plasma with a temperature of up to 35,000K

    Microsoft Academic Search

    E. A. Ershov-Pavlov; L. I. Kiselevskii; V. D. Shimanovich

    1969-01-01

    We consider two versions of heavy-current arc discharge chambers with vortex stabilization, making possible the production of an air plasma to a temperature of 35,000K, without contamination by electrode material. We study the space-time stability of the plasma formations that are produced.

  7. Photoconductive Detectors with Fast Temporal Response for Laser Produced Plasma Experiments

    SciTech Connect

    M. J. May, C. Halvorson, T. Perry, F. Weber, P. Young, C. Silbernagel

    2008-06-01

    Processes during laser plasma experiments typically have time scales that are less than 100 ps. The measurement of these processes requires X-ray detectors with fast temporal resolution. We have measured the temporal responses and linearity of several different Xray sensitive Photoconductive Detectors (PCDs). The active elements of the detectors investigated include both diamond (natural and synthetic) and GaAs crystals. The typical time responses of the GaAs PCDs are approximately 60 ps, respectively. Some characterizations using X-ray light from a synchrotron light source are presented.

  8. Photoconductive Detectors with Fast Temporal Response for Laser Produced Plasma Experiments.

    SciTech Connect

    May, M; Halvorson, C; Perry, T; Weber, F; Young, P; Silbernagel, C

    2008-05-06

    Processes during laser plasma experiments typically have time scales that are less than 100 ps. The measurement of these processes requires X-ray detectors with fast temporal resolution. We have measured the temporal responses and linearity of several different X-ray sensitive Photoconductive Detectors (PCDs). The active elements of the detectors investigated include both diamond (natural and synthetic) and GaAs crystals. The typical time responses of the GaAs PCDs are approximately 60 ps, respectively. Some characterizations using X-ray light from a synchrotron light source are presented.

  9. Experiments on radiative collapse in laser-produced plasmas relevant to astrophysical jets

    PubMed

    Shigemori; Kodama; Farley; Koase; Estabrook; Remington; Ryutov; Ochi; Azechi; Stone; Turner

    2000-12-01

    We report a laser experiment of astrophysical interest on radiative jet formation. Conically shaped targets are irradiated by intense laser light. An ablated plasma flow collides at the axis of the cone targets, then propagates at high Mach number, forming a jetlike structure. We measure time-resolved x-ray self-emission images from the jets. The diameter of the jet increases with decreasing atomic number of the irradiated target, suggesting that the collimation is due to radiative cooling. Two-dimensional simulations reproduce essential features of the experimental results. PMID:11138197

  10. Solid oxide fuel cell electrolytes produced via very low pressure suspension plasma spray and electrophoretic deposition

    NASA Astrophysics Data System (ADS)

    Fleetwood, James D.

    Solid oxide fuel cells (SOFCs) are a promising element of comprehensive energy policies due to their direct mechanism for converting the oxidization of fuel, such as hydrogen, into electrical energy. Both very low pressure plasma spray and electrophoretic deposition allow working with high melting temperature SOFC suspension based feedstock on complex surfaces, such as in non-planar SOFC designs. Dense, thin electrolytes of ideal composition for SOFCs can be fabricated with each of these processes, while compositional control is achieved with dissolved dopant compounds that are incorporated into the coating during deposition. In the work reported, sub-micron 8 mole % Y2O3-ZrO2 (YSZ) and gadolinia-doped ceria (GDC), powders, including those in suspension with scandium-nitrate dopants, were deposited on NiO-YSZ anodes, via very low pressure suspension plasma spray (VLPSPS) at Sandia National Laboratories' Thermal Spray Research Laboratory and electrophoretic deposition (EPD) at Purdue University. Plasma spray was carried out in a chamber held at 320 - 1300 Pa, with the plasma composed of argon, hydrogen, and helium. EPD was characterized utilizing constant current deposition at 10 mm electrode separation, with deposits sintered from 1300 -- 1500 C for 2 hours. The role of suspension constituents in EPD was analyzed based on a parametric study of powder loading, powder specific surface area, polyvinyl butyral (PVB) content, polyethyleneimine (PEI) content, and acetic acid content. Increasing PVB content and reduction of particle specific surface area were found to eliminate the formation of cracks when drying. PEI and acetic acid content were used to control suspension stability and the adhesion of deposits. Additionally, EPD was used to fabricate YSZ/GDC bilayer electrolyte systems. The resultant YSZ electrolytes were 2-27 microns thick and up to 97% dense. Electrolyte performance as part of a SOFC system with screen printed LSCF cathodes was evaluated with peak power densities as high as 520 mW/cm2 at 800 C for YSZ and 350 mW/cm 2 at 800 C for YSZ/GDC bilayer electrolytes.

  11. Vacuum laser-produced plasma for analytical application in fusion technologies

    NASA Astrophysics Data System (ADS)

    Almaviva, S.; Caneve, L.; Colao, F.; Fantoni, R.; Maddaluno, G.

    2012-12-01

    LIBS is a well established tool for qualitative, semi-quantitative and quantitative analysis of surfaces, with micro-destructive characteristics and some capabilities for stratigraphy. In this work, the depth profiling capabilities of LIBS has been checked by determining the composition of multilayered samples simulating the plasma facing components fusion device covered with co-deposited impurity layers. A new experimental setup has been designed and realized in order to optimize the characteristics of a LIBS system working at low pressure and remotely.

  12. Magnetic properties of Sm5Fe17/Fe composite magnets produced by spark plasma sintering method

    NASA Astrophysics Data System (ADS)

    Saito, Tetsuji; Miyoshi, Hiroya

    2012-04-01

    Mixtures of powdered Sm5Fe17 melt-spun ribbon and Fe powder were consolidated into bulk magnets by the spark plasma sintering (SPS) method. Although these bulk magnets consisted of the hard magnetic Sm5Fe17 and soft magnetic ?-Fe phases, they had a smooth hysteresis loop and exhibited coercivity. Among the magnets studied, the Sm5Fe17/Fe composite magnet with 30%Fe showed a remanence of 94 emu/g with a coercivity of 2.9 kOe.

  13. Design of Layered Metal-Ceramic FGMs Produced by Spark Plasma Sintering

    NASA Astrophysics Data System (ADS)

    Casari, Francesco; Zadra, Mario; Girardini, Luca; Molinari, Alberto

    2008-02-01

    The production of layered Nickel-Alumina FGMs by means of Spark Plasma Sintering is studied by investigating the effect of sintering under temperature gradient on final properties, i.e. density, hardness and fracture toughness. Results demonstrate that alumina powder can be fully densified at 1400 C, whilst a temperature of 1050 C is sufficient to consolidate nickel powder. The temperature gradient, obtained with the proper design of the die configuration, is useful for reduction of thermal stresses, but does not permit the full consolidation of the intermediate layers.

  14. Chemically produced tungsten-praseodymium oxide composite sintered by spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Ding, Xiao-Yu; Luo, Lai-Ma; Lu, Ze-Long; Luo, Guang-Nan; Zhu, Xiao-Yong; Cheng, Ji-Gui; Wu, Yu-Cheng

    2014-11-01

    Pr2O3 doped W composite were synthesized by a novel wet chemical method and spark plasma sintering. The grain size, relative density and the Vicker hardness HV0.2 of Pr2O3/W samples were 4 ?m, 98.3% and 377.2, respectively. The tensile strength values of Pr2O3/W were higher than those of pure W. As the temperature rises from 25 C to 800 C, the conductivity of pure W and W-1 wt% Pr2O3 composites decreased with the same trend, was above 150 W/m K.

  15. Studies of ion kinetic effects in shock-driven inertial confinement fusion implosions at OMEGA and the NIF and magnetic reconnection using laser-produced plasmas at OMEGA

    E-print Network

    Rosenberg, Michael Jonathan

    2014-01-01

    Studies of ion kinetic effects during the shock-convergence phase of inertial confinement fusion (ICF) implosions and magnetic reconnection in strongly-driven, laser-produced plasmas have been facilitated by the use of ...

  16. Biostability of Batracylin: Incubation of batracylin in mouse and human plasma for as long as 48 h did not produce significant degradation

    Cancer.gov

    Batracyclin Pharmacology Abstract Division of Cancer Treatment and Diagnosis National Cancer Institute Biostability of Batracylin: Incubation of batracylin in mouse and human plasma for as long as 48 h did not produce significant degradation.

  17. Dynamics and manipulation of the dominant 13.5 nm in-band extreme ultraviolet emitting region of laser-produced Sn plasmas

    NASA Astrophysics Data System (ADS)

    Yuspeh, Samuel Edward

    Laser-produced Sn plasmas have been extensively studied as an efficient soft x-ray light source for next generation high volume manufacturing of semiconductor microchips. One of the main areas of focus is to increase the conversion efficiency, laser to 13.5 nm 2% bandwidth extreme ultraviolet (EUV) light. Previous experiments have been conducted without a tight control of the initial parameters and are not thoroughly diagnosed, leading to assumptions that only exist under unique conditions and/or parameter spaces. This becomes important, as a new need for a much smaller EUV light source for metrology has emerged. The focus is the size of the dominant in-band EUV emitting region, which is not typically measured. The target geometry, laser focal spot size and laser intensity are numerically and experimentally investigated focusing on the underlying physics that governs the ability to modify the size and properties of the EUV emitting region. A combination of experimental data coupled with numerical simulations are used to show the impact of a 1.064 mum laser's absorption depth on the heating and EUV emission of a Sn plasma. Most notably, the core of the plasma is "overheated" beyond that required to efficiently emit EUV light, to allow the optimal temperature to expand to a region with lower density that is more optically thin. The ratio of Sn sphere diameter to laser focal spot size did not change the size of the EUV emitting region. However, the electron densities in the emitting region as well as the surrounding plasma were manipulated by target geometry. Reducing the laser focal spot size from one that is required for lithography to one that may be used for metrology produces a shorter electron density scale length due to increase lateral expansion. This generates a higher conversion efficiency, smaller and slightly brighter EUV light source. Varying the laser intensity using a small laser spot size affected the peak electron temperature and the size of the EUV emitting region. The amount of lateral expansion also varied with the laser intensity, thus affecting the brightness, conversion efficiency and duration of emission of EUV light.

  18. Thomson scattering from laser-produced gold plasmas in radiation conversion layer

    SciTech Connect

    Wang Zhebin; Zheng Jian; Zhao Bin; Yu, C.X.; Jiang Xiaohua; Li Wenhong; Liu Shenye; Ding Yongkun; Zheng Zhijian [CAS Key Laboratory of Basic Plasma Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China) and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China)

    2005-08-15

    With a 263.3 nm probe laser beam, the Thomson scattering (TS) spectra are measured at the distance from the surface of gold disc targets as close as 50 {mu}m. All of the TS spectra become narrower with time, which indicates the overall drop of plasma temperature as the high-Z plasmas blow off. The experimental data show that there are distinct characteristics between the inner region (i.e., 50 and 100 {mu}m away from target surface) and the outer region. The gradient of the electron temperature in outer region is toward the target and becomes opposite to that in the inner region. The asymmetries of the TS spectra in the inner region are in good agreement with calculation based on the Spitzer-Haerm theory. In the outer region, however, the discrepancies between the experiments and calculations are significant, which may be a hint that the electron energy transport becomes flux limited or nonlocal in this region.

  19. Plasma-produced phase-pure cuprous oxide nanowires for methane gas sensing

    SciTech Connect

    Cheng, Qijin, E-mail: ijin.cheng@xmu.edu.cn; Zhang, Fengyan [School of Energy Research, Xiamen University, Xiamen City, Fujian Province 361005 (China); Yan, Wei [School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales 2052 (Australia); Plasma Nanoscience Laboratories, CSIRO Materials Science and Engineering, Lindfield, New South Wales 2070 (Australia); Randeniya, Lakshman [Plasma Nanoscience Laboratories, CSIRO Materials Science and Engineering, Lindfield, New South Wales 2070 (Australia); Ostrikov, Kostya [Plasma Nanoscience Laboratories, CSIRO Materials Science and Engineering, Lindfield, New South Wales 2070 (Australia); Plasma Nanoscience, School of Physics, The University of Sydney, Sydney, New South Wales 2006 (Australia)

    2014-03-28

    Phase-selective synthesis of copper oxide nanowires is warranted by several applications, yet it remains challenging because of the narrow windows of the suitable temperature and precursor gas composition in thermal processes. Here, we report on the room-temperature synthesis of small-diameter, large-area, uniform, and phase-pure Cu{sub 2}O nanowires by exposing copper films to a custom-designed low-pressure, thermally non-equilibrium, high-density (typically, the electron number density is in the range of 10{sup 11}10{sup 13}?cm{sup ?3}) inductively coupled plasmas. The mechanism of the plasma-enabled phase selectivity is proposed. The gas sensors based on the synthesized Cu{sub 2}O nanowires feature fast response and recovery for the low-temperature (?140?C) detection of methane gas in comparison with polycrystalline Cu{sub 2}O thin film-based gas sensors. Specifically, at a methane concentration of 4%, the response and the recovery times of the Cu{sub 2}O nanowire-based gas sensors are 125 and 147?s, respectively. The Cu{sub 2}O nanowire-based gas sensors have a potential for applications in the environmental monitoring, chemical industry, mining industry, and several other emerging areas.

  20. Faraday cup measurements of the plasma plume produced at an x-ray converter

    SciTech Connect

    Garcia, M; Houck, T L; Sampayan, S E

    1998-08-17

    The next generation of radiographic machines based on induction accelerators is expected to generate multiple, small diameter x-ray spots of high intensity. Experiments to study the interaction of the electron beam with the x-ray converter are being performed at the Lawrence Livermore National Laboratory (LLNL) using the 6-MeV, 2-kA Experimental Test Accelerator (ETA) electron beam. The physics issues of greatest concern can be separated into two categories. The multiple pulse issue involves the interaction of subsequent beam pulses with the expanding plasma plume generated by earlier pulses striking the x-ray converter. The plume expands at several millimeters per microsecond and defines the minimum transverse spacing of the pulses. The single pulse issue is more subtle and involves the extraction of light ions by the head of the beam pulse. These light ions might propagate at velocities of several millimeters per nanosecond through the body of the incoming pulse resulting in a moving focus prior to the converter. In this paper we describe Faraday cup measurements performed to quantify the plasma plume expansion and velocities of light ions.

  1. High energy and density plasmas produced by UHI interaction and buried-layer targets

    NASA Astrophysics Data System (ADS)

    Baton, Sophie; Dervieux, Vincent; Loupias, Berenice; Blancard, Christophe; Bowen, Christopher; Gremillet, Laurent; Lecherbourg, Ludovic; Pain, Jean-Christophe; Reverdin, Charles; Renaudin, Patrick; Rousseaux, Christophe; Silvert, Virginie; Allan, Peter; Brown, Colin; Hill, Matthew; Hoarty, David

    2013-10-01

    The radiative properties of hot (hundreds of eV), dense (rho ~ rhosol) plasmas are of interest in several research fields including inertial confinement fusion and astrophysics. The achieved plasma conditions (temperature, density, LTE/NLTE) have to be well characterized to constrain equation of state and opacity models. Ongoing progresses in ultra-intense laser facilities have led to the experimental demonstration of laser-driven isochoric heating of solid-density, micrometer targets to high temperatures (>100 eV). Here, we report on a recent experiment carried out with the ELFIE at LULI. The ultra-fast heating of various targets (multi-layered and reduced-mass targets) by using different laser conditions (1w and 2w) was inferred from their thermal x-ray emission. Two main diagnostics were used: a time-integrated Von Hamos crystal spectrometer and a toroidal crystal spectrometer coupled to an x-ray streak camera. According to combined atomic physics and hydrodynamic calculations, the measurements are consistent with densities rho ~ rhosol and maximum temperatures T ~ 450 eV.

  2. Inactivation of Salmonella enterica serovar Typhimurium on fresh produce by cold atmospheric gas plasma technology.

    PubMed

    Fernndez, A; Noriega, E; Thompson, A

    2013-02-01

    Cold atmospheric gas plasma treatment (CAP) is an alternative approach for the decontamination of fresh and minimally processed food. In this study, the effects of growth phase, growth temperature and chemical treatment regime on the inactivation of Salmonella enterica serovar Typhimurium (S. Typhimurium) by Nitrogen CAP were examined. Furthermore, the efficacy of CAP treatment for decontaminating lettuce and strawberry surfaces and potato tissue inoculated with S. Typhimurium was evaluated. It was found that the rate of inactivation of S. Typhimurium was independent of the growth phase, growth temperature and chemical treatment regime. Under optimal conditions, a 2 min treatment resulted in a 2.71 log-reduction of S. Typhimurium viability on membrane filters whereas a 15 min treatment was necessary to achieve 2.72, 1.76 and 0.94 log-reductions of viability on lettuce, strawberry and potato, respectively. We suggest that the differing efficiency of CAP treatment on the inactivation of S. Typhimurium on these different types of fresh foods is a consequence of their surface features. Scanning electron microscopy of the surface structures of contaminated samples of lettuce, strawberry and potato revealed topographical features whereby S. Typhimurium cells could be protected from the active species generated by plasma. PMID:23122497

  3. Shift and width of the Balmer series H? line at high electron density in a laser-produced plasma

    NASA Astrophysics Data System (ADS)

    Kielkopf, John F.; Allard, Nicole F.

    2014-08-01

    Time-resolved profiles of the Balmer series H? line emitted by a laser-produced hydrogen plasma have been measured to determine the shift and width for electron densities from below 1018 to above 1020 cm-3 at an average temperature of 28000 K. Fits of the profiles that allow for self-absorption in the plasma yield shifts and widths that are consistent with experiments on lower density and cooler gas-liner pinch plasmas. The width scales as N_{e}^{0.70+/- 0.03} and the shift as N_{e}^{0.92+/- 0.03} between 8.7\\times {{10}^{17}} and 1.4\\times {{10}^{20}} cm-3. H? shifts monotonically and nearly linearly to the red with increasing density under the reported conditions. A comparison to theory calculations using exact potentials for H_{2}^{+} shows that an intrinsic asymmetry becomes significant only in the upper limit of this range when a satellite develops in the far red wing.

  4. Formation of hot spots in the plasma of a Z-pinch produced from low-density deuterated polyethylene

    SciTech Connect

    Akunets, A. A. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Anan'ev, S. S.; Bakshaev, Yu. L.; Blinov, P. I.; Bryzgunov, V. A.; Vikhrev, V. V.; Volobuev, I. V.; Dan'ko, S. A.; Zelenin, A. A.; Kazakov, E. D.; Korolev, V. D.; Meshcherov, B. R.; Nedoseev, S. L. [Russian Research Centre Kurchatov Institute (Russian Federation); Pimenov, V. G. [Russian Academy of Sciences, Zelinsky Institute of Organic Chemistry (Russian Federation); Smirnova, E. A.; Ustroev, G. I.; Chernenko, A. S.; Shchagin, V. A. [Russian Research Centre Kurchatov Institute (Russian Federation)

    2010-08-15

    Results are presented from experimental studies of the plasma formation dynamics in a Z-pinch produced from a cylindrical microporous agar-agar load. The experiments were performed on the S-300 facility at a current of 2 MA and current rise time of 100 ns. To enhance the energy concentration, a deuterated polyethylene neck with a mass density of 50-75 {mu}g/cm{sup 3} and diameter of 1-2 mm was made in the central part of the load. The spatiotemporal characteristics of the Z-pinch were studied using an optical streak camera and fast frame photography in the optical and soft X-ray spectral ranges. X-ray emission was detected using semiconductor and vacuum diodes, and neutron emission was studied by means of the time-of-flight method. It is found that, in the course of continuous plasma production, hot spots with a diameter of 100 {mu}m form in the pinch plasma. The hot spots emit short soft X-ray pulses with a duration of 2-4 ns, as well as neutron pulses with an average neutron energy of about 2.45 MeV. The maximum neutron yield was found to be 4.5 x 10{sup 9} neutrons per shot. The scenario of hot spot formation is adequately described by two-dimensional MHD simulations.

  5. High resolution soft x-ray spectroscopy of low Z K-shell emission from laser-produced plasmas.

    PubMed

    Dunn, J; Magee, E W; Shepherd, R; Chen, H; Hansen, S B; Moon, S J; Brown, G V; Gu, M-F; Beiersdorfer, P; Purvis, M A

    2008-10-01

    A large radius, R=44.3 m, high resolution grating spectrometer (HRGS) with 2400 lines/mm variable line spacing has been designed for laser-produced plasma experiments conducted at the Lawrence Livermore National Laboratory Jupiter Laser Facility. The instrument has been run with a low-noise, charge-coupled device detector to record high signal-to-noise spectra in the 10-50 A wavelength range. The instrument can be run with a 10-20 microm wide slit to achieve the best spectral resolving power, approaching 1000 and similar to crystal spectrometers at 12-20 A, or in slitless operation with a small symmetrical emission source. We describe preliminary spectra emitted from various H-like and He-like low Z ion plasmas heated by 100-500 ps (full width at half maximum), 527 nm wavelength laser pulses. This instrument can be developed as a useful spectroscopy platform relevant to laboratory-based astrophysics as well as high energy density plasma studies. PMID:19044476

  6. High resolution soft x-ray spectroscopy of low Z K-shell emission from laser-produced plasmas

    SciTech Connect

    Dunn, J; Magee, E W; Shepherd, R; Chen, H; Hansen, S B; Moon, S J; Brown, G V; Gu, M; Beiersdorfer, P; Purvis, M A

    2008-05-21

    A large radius, R = 44.3 m, High Resolution Grating Spectrometer (HRGS) with 2400 line/mm variable line spacing has been designed for laser-produced plasma experiments conducted at the Lawrence Livermore National Laboratory Jupiter Laser Facility. The instrument has been run with a low-noise, charge-coupled device detector to record high signal-to-noise spectra in the 10-50 {angstrom} wavelength range. The instrument can be run with a 10-20 {micro}m wide slit to achieve the best spectral resolving power, approaching 1000 and similar to crystal spectrometers at 12-20 {angstrom}, or in slitless operation with a small symmetrical emission source. We describe preliminary spectra emitted from various H-like and He-like low Z ion plasmas heated by 100-500 ps (FWHM), 527 nm wavelength laser pulses. This instrument can be developed as a useful spectroscopy platform relevant to laboratory-based astrophysics as well as high energy density plasma studies.

  7. Optical observations of post-discharge phenomena of laser-triggered discharge produced plasma for EUV lithography

    NASA Astrophysics Data System (ADS)

    Lim, Soowon; Kitajima, Seiya; Lu, Peng; Sakugawa, Takashi; Akiyama, Hidenori; Katsuki, Sunao; Teramoto, Yusuke

    2015-01-01

    This paper reports the dynamic post-discharge phenomena of laser-triggered discharge-produced plasmas (LTDPP) for extreme ultraviolet lithography (EUVL) sources. A pulsed laser was focused on the high-voltage tin cathode surface to form tin vapor jet across a 5 mm long anodecathode gap, which leads to the electrical breakdown. The post-discharge phenomena were observed using both of the Schlieren method and high-speed camera. Schlieren images show the dynamic evolution of the discharge plasma and the development of tin droplets. Visible emission from the plasma lasted for more than 1 s after the current stopped. The droplets emerged from the cathode approximately 100 s after discharge and spread throughout the electrodes gap. Various sizes of droplets stagnate in the gap for milliseconds. The subsequent laser pulse and voltage application show an interaction between the droplets and the subsequent discharge. The subsequent laser pulse evaporates not only the cathode surface but also the droplets, which influence the tin vapor distribution in the gap. This uncertain vapor distribution affects the formation process of microplasmas that emit EUV.

  8. Characteristics of extreme ultraviolet emission from a discharge-produced potassium plasma for surface morphology application

    SciTech Connect

    Higashiguchi, Takeshi; Yugami, Noboru [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Terauchi, Hiromitsu; Yatagai, Toyohiko [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Sasaki, Wataru [NTP Inc., Gakuen Kibanadai Nishi 1-1, Miyazaki 889-2192 (Japan); D'Arcy, Rebekah; Dunne, Padraig; O'Sullivan, Gerry [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)

    2010-03-29

    We have demonstrated a discharge-produced microplasma extreme ultraviolet source based on a pure potassium vapor. Potassium ions produced strong broadband emission around 40 nm with a bandwidth of 8 nm (full width at half-maximum). The current-voltage characteristics of microdischarge suggest that the source operates in a hollow cathode mode. By comparison with atomic structure calculations, the broadband emission is found to be primarily due to 3d-3p transitions in potassium ions ranging from K{sup 2+} to K{sup 4+}.

  9. Implementation of a 3D PIC/MCC Simulation to Investigate Plasma Initiation in Nitrogen at Atmospheric Pressure

    NASA Astrophysics Data System (ADS)

    Fierro, Andrew; Dickens, James; Neuber, Andreas

    2013-09-01

    The particle-particle interactions involved in plasma formation are well suited to implement in a parallel environment due to the identical computations done for each particle. Specifically, a 3D PIC/MCC simulation was accelerated on an NVIDIA graphics processing unit (GPU) using the CUDA framework for a developing plasma in nitrogen gas at atmospheric pressure to study the initial phase of breakdown. For this simulation, the computational volume was ~220 mm3 with 15 ?m spatial resolution containing two parabolic electrodes. The plasma development is typically characterized by the development of positive ion space charge creating a localized field enhancement thus accelerating ionization processes in this region. For instance, with the application of an 8 kV/cm electric field amplitude, after 1 ns into the simulation, the development of positive ion space charge near both anode and cathode is observed with the densities of ~1016 cm-3 and ~1014 - 1015 cm-3, respectively, while the electron density sits at ~1011 cm-3. Already 100 ps into the simulation, the distribution of electron energies exhibits non-thermal characteristics with an average electron energy of 0.98 eV that increases to ~10 eV at 1 ns. The particle-particle interactions involved in plasma formation are well suited to implement in a parallel environment due to the identical computations done for each particle. Specifically, a 3D PIC/MCC simulation was accelerated on an NVIDIA graphics processing unit (GPU) using the CUDA framework for a developing plasma in nitrogen gas at atmospheric pressure to study the initial phase of breakdown. For this simulation, the computational volume was ~220 mm3 with 15 ?m spatial resolution containing two parabolic electrodes. The plasma development is typically characterized by the development of positive ion space charge creating a localized field enhancement thus accelerating ionization processes in this region. For instance, with the application of an 8 kV/cm electric field amplitude, after 1 ns into the simulation, the development of positive ion space charge near both anode and cathode is observed with the densities of ~1016 cm-3 and ~1014 - 1015 cm-3, respectively, while the electron density sits at ~1011 cm-3. Already 100 ps into the simulation, the distribution of electron energies exhibits non-thermal characteristics with an average electron energy of 0.98 eV that increases to ~10 eV at 1 ns. Work supported by an AFOSR grant on the Basic Physics of Plasma Discharges with student fellowship support provided by NPSC.

  10. Three dimensional analysis of longitudinal plasma oscillations in a thermal relativistic electron beam: Application to an initial value problem

    SciTech Connect

    Marinelli, Agostino [Particle Beam Physics Laboratory, Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095 (United States); Universita degli Studi di Roma La Sapienza, Via Antonio Scarpa 14, Rome 00161 (Italy); Hemsing, Erik [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Rosenzweig, James B. [Particle Beam Physics Laboratory, Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095 (United States)

    2012-06-15

    In this paper, we study the initial value problem of longitudinal plasma oscillations in a relativistic electron beam. Our analysis is based on the formalism developed in Marinelli et al.[Phys. Plasmas 18, 103105 (2011)]. We study the evolution of an arbitrary six-dimensional phase-space perturbation under the effect of longitudinal space-charge forces, with the inclusion of three-dimensional effects due to the finite size of the beam, transverse betatron motion, and longitudinal thermal motion induced by both energy-spread and transverse emittance. We expand the phase-space perturbation in a series of eigenmodes of a Schroedinger-like equation, corresponding to a set of propagating space-charge waves. We develop a general formalism, which we use to find explicit expressions for the evolution of an initial perturbation coupled to the fundamental plasma eigenmode. This work has important applications in the theory of space-charge instabilities in high brightness electron beams and control of shot-noise in seeded free-electron lasers. We discuss the application of the present theory to a specific experimental scenario corresponding to a shot-noise suppression scheme at optical wavelengths.

  11. Fe-based metallic glass coatings produced by smart plasma spraying process

    Microsoft Academic Search

    Akira Kobayashi; Shoji Yano; Hisamichi Kimura; Akihisa Inoue

    2008-01-01

    Metallic glass has excellent functions such as high toughness and corrosion resistance. Therefore it is one of the most attractive materials, and many researchers have conducted various developmental research works. However, the metallic glass material is expensive and a composite material is preferred for the industrial application. Thermal spraying method is a potential candidate to produce metallic glass composites. The

  12. Influence of magnetic field on laser-produced barium plasmas: Spectral and dynamic behaviour of neutral and ionic species

    NASA Astrophysics Data System (ADS)

    Raju, Makaraju Srinivasa; Singh, R. K.; Gopinath, Pramod; Kumar, Ajai

    2014-10-01

    The expansion dynamics and spectral behaviour of plasma produced by a Nd:YAG laser (? = 1.064 ?m, pulse width: 8 ns) from barium target and expanding in 0.45 T transverse magnetic field in vacuum (10-5 Torr pressure) are investigated using time-of-flight optical emission spectroscopy. The experiments are carried out at various laser fluences from 12 to 31 J/cm2. The temporal profiles of neutral (Ba I 553.5 and 577.7 nm) lines are temporally broadened, while that of ionic (Ba II 413.0 and 455.4 nm) lines show strong confinement in the presence of a magnetic field. In the absence of magnetic field, the temporal profile of Ba I 553.5 nm is exactly reproduced by fitting with two Shifted Maxwell Boltzmann (SMB) Distribution components, while in the presence of a magnetic field the profile could only be fitted with three components. The field enhanced and field induced SMB components of neutral profile are correlated with populations of ground state, metastable states, and long-lived Rydberg states present in the barium plasma, while SMB components of ionic lines are explained on the basis of the presence of super-elastic collisions among the excited species in the plasma. The spatial variation of electron temperature and temporal variation of electron density are deduced and correlated to the different collisional processes in the barium plasma. The ionic profiles show efficient confinement in the presence of a magnetic field at higher fluences.

  13. Ruminant-produced trans-fatty acids raise plasma total and small HDL particle concentrations in male Hartley guinea pigs.

    PubMed

    Rice, Beth H; Kraft, Jana; Destaillats, Frdric; Bauman, Dale E; Lock, Adam L

    2010-12-01

    Although trans-fatty acid (tFA) intake has been positively associated with coronary heart disease (CHD), the relative effect of consuming industrially produced (IP)- compared with ruminant-produced (RP)-tFA on CHD risk factors is unclear. This study was designed to examine the effects of feeding partially hydrogenated vegetable oil (PHVO), IP-tFA source, and butter oil (BO), RP-tFA source, on the development of atherosclerosis and risk factors associated with CHD. Forty-eight male Hartley guinea pigs were fed a hypercholesterolemic diet containing (9% by weight) PHVO, BO, coconut oil (CO; positive control), or soybean oil (SO; negative control) for 8 or 12 wk (n = 6/group). Morphological analysis revealed that none of the groups developed atherosclerosis. Plasma and hepatic lipids did not differ between the tFA groups, but total and small HDL particles were significantly higher in the BO group than in the PHVO group and mean HDL particle size was significantly smaller in the BO group than in the PHVO group. Compared with the other treatment groups, the SO treatment resulted in significantly lower total cholesterol (TC) and LDL cholesterol in plasma, whereas hepatic TC was significantly higher in the SO group than in the other treatment groups. Plasma and hepatic cholesterol concentrations did not differ between the tFA and CO treatments. These results demonstrate that when fed at a high dose, IP- and RP-tFA had the same effect on established CHD risk factors in male Hartley guinea pigs. The effects of RP-tFA on HDL particle sizes and concentrations warrant further investigation. PMID:20980644

  14. Simultaneously time- and space-resolved spectroscopic characterization of laser-produced plasmas

    SciTech Connect

    Charatis, G.; Young, B.K.F.; Busch, G.E.; Cerjan, C.J.; Goldstein, W.H.; Osterheld, A.L.; Phillips, T.W.; Rosen, M.D.; Stewart, R.E.; Walling, R.S.

    1988-03-03

    The CHROMA laser facility at KMS Fusion has been used to irradiate a variety of microdot targets. These include aluminum dots and mixed bromine dots doped with K-shell (magnesium) emitters. Simultaneously time- and space-resolved K-shell and L-shell spectra have been measured and compared to dynamic model predictions. The electron density profiles are measured using holographic interferometry. Temperatures, densities, and ionization distributions are determined using K-shell and L-shell spectral techniques. Time and spatial gradients are resolved simultaneously using three diagnostics: a framing crystal x-ray spectrometer, an x-ray streaked crystal spectrometer with a spatial imaging slit, and a 4-frame holographic interferometer. Significant differences have been found between the interferometric and the model-dependent spectral measurements of plasma density. Predictions by new non-stationary L-shell models currently being developed are also presented. 14 refs., 10 figs.

  15. System to continuously produce carbon fiber via microwave assisted plasma processing

    DOEpatents

    White, Terry L; Paulauskas, Felix L; Bigelow, Timothy S

    2014-03-25

    A method for continuously processing carbon fiber including establishing a microwave plasma in a selected atmosphere contained in an elongated chamber having a microwave power gradient along its length defined by a lower microwave power at one end and a higher microwave power at the opposite end of the elongated chamber. The elongated chamber having an opening in each of the ends of the chamber that are adapted to allow the passage of the fiber tow while limiting incidental gas flow into or out of said chamber. A continuous fiber tow is introduced into the end of the chamber having the lower microwave power. The fiber tow is withdrawn from the opposite end of the chamber having the higher microwave power. The fiber to is subjected to progressively higher microwave energy as the fiber is being traversed through the elongated chamber.

  16. Optimizing conversion efficiency and reducing ion energy in a laser-produced Gd plasma

    SciTech Connect

    Cummins, Thomas; Li Bowen; O'Gorman, Colm; Dunne, Padraig; Sokell, Emma; O'Sullivan, Gerry [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Otsuka, Takamitsu [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Yugami, Noboru; Higashiguchi, Takeshi [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Jiang Weihua [Department of Electrical Engineering, Nagaoka University of Technology, Kami-tomiokamachi 1603-1, Nagaoka, Niigata 940-2188 (Japan); Endo, Akira [Research Institute for Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan)

    2012-02-06

    We have demonstrated an efficient extreme ultraviolet (EUV) source at 6.7 nm by irradiating Gd targets with 0.8 and 1.06 {mu}m laser pulses of 140 fs to 10 ns duration. Maximum conversion efficiency of 0.4% was observed within a 0.6% bandwidth. A Faraday cup observed ion yield and time of flight signals for ions from plasmas generated by each laser. Ion kinetic energy was lower for shorter pulse durations, which yielded higher electron temperatures required for efficient EUV emission, due to higher laser intensity. Picosecond laser pulses were found to be the best suited to 6.7 nm EUV source generation.

  17. Inhomogeneity of plasma formed in high-current discharge channels under different methods of initiation

    Microsoft Academic Search

    S. I. Andreev; E. A. Zobov; A. N. Sidorov; T. I. Smirnova; V. G. Sokolov

    1980-01-01

    Different methods for the initiation of meter-length discharges in air at atmospheric pressure were experimentally studied and compared. Studies were conducted for a discharge capacitance of 27 microfarads, a voltage of 30 kV, a discharge gap of 20-50 cm, and an initial current of 67 kA. It is shown that methods of initiation that involve exploding foils, exploding wires, exploding

  18. Plasma nonuniformities of the channel of a high-power discharge initiated by various methods

    NASA Astrophysics Data System (ADS)

    Andreev, S. I.; Zobov, E. A.; Sidorov, A. N.; Smirnova, T. I.; Sokolov, V. G.

    1980-10-01

    Different methods for the initiation of meter-length discharges in air at atmospheric pressure were experimentally studied and compared. Studies were conducted for a discharge capacitance of 27 microfarads, a voltage of 30 kV, a discharge gap of 20-50 cm, and an initial current of 67 kA. It is shown that methods of initiation that involve exploding foils, exploding wires, exploding graphite threads, and multiple sparks lead to the formation of small initial inhomogeneities in the discharge channel that continue to exist in the high-current stage. The excitation of the discharge by a sliding spark occurs without the formation of inhomogeneities.

  19. Generation mechanism of hydroxyl radical species and its lifetime prediction during the plasma-initiated ultraviolet (UV) photolysis

    NASA Astrophysics Data System (ADS)

    Attri, Pankaj; Kim, Yong Hee; Park, Dae Hoon; Park, Ji Hoon; Hong, Young J.; Uhm, Han Sup; Kim, Kyoung-Nam; Fridman, Alexander; Choi, Eun Ha

    2015-03-01

    Through this work, we have elucidated the mechanism of hydroxyl radicals (OH) generation and its life time measurements in biosolution. We observed that plasma-initiated ultraviolet (UV) photolysis were responsible for the continues generation of OH species, that resulted in OH to be major reactive species (RS) in the solution. The density and lifetime of OH species acted inversely proportional to each other with increasing depth inside the solution. The cause of increased lifetime of OH inside the solution is predicted using theoretical and semiempirical calculations. Further, to predict the mechanism of conversion of hydroxide ion (OH-) to OH or H2O2 (hydrogen peroxide) and electron, we determined the current inside the solution of different pH. Additionally, we have investigated the critical criterion for OH interaction on cancer cell inducing apoptosis under effective OH exposure time. These studies are innovative in the field of plasma chemistry and medicine.

  20. Effect of $q\\bar q$ Initial-state Interaction on Dilepton Emission Rate from Quark-Gluon Plasma

    E-print Network

    M. G. -H. Mostafa; Cheuk-Yin Wong; Lali Chatterjee; Zhong-Qi Wang

    1995-12-18

    We calculate the dilepton production rate from a thermalized quark-gluon plasma in heavy-ion collisions at RHIC energies. Higher-order QCD corrections are included by using an analytical correction factor $K^{(i)}$, which takes into account the $q\\bar q$ initial-state interactions. We show that the analytic correction factor gives very good agreement with experimental Drell-Yan data and leads to large enhancement of the thermal dilepton emission rates. We compare the thermal dilepton yields with the expected production from open-charm decays and Drell-Yan background and assess the prospects of observing thermal dileptons from the quark-gluon-plasma at invariant masses of a few GeV.

  1. Short Wavelength Laser Gain Studies in Plasmas Produced by a Small NEODYMIUM:GLASS Slab Laser

    Microsoft Academic Search

    Martin Heinrich Muendel

    1994-01-01

    A high-power, high-repetition-rate Nd:glass laser system was developed and used to study a collisionally pumped x-ray laser scheme near 200 A. The laser system used a commercial oscillator injecting 60-psec modelocked pulses at 1053 nm into a Nd:glass zig-zag slab amplifier which was developed for this project. The amplifier was capable of producing 2-J, near-diffraction-limited pulses at repetition rates of

  2. Observation of neutron spectrum produced by fast deuterons via ultraintense laser plasma interactions

    Microsoft Academic Search

    N. Izumi; Y. Sentoku; H. Habara; K. Takahashi; F. Ohtani; T. Sonomoto; R. Kodama; T. Norimatsu; H. Fujita; Y. Kitagawa; K. Mima; K. A. Tanaka; T. Yamanaka

    2002-01-01

    We report the first precise spectral measurement of fast neutrons produced in a deuterated plastic target irradiated by an ultraintense sub-picosecond laser pulse. The 500-fs, 50-J, 1054-nm laser pulse was focused on the deuterated polystyrene target with an intensity of 21019 W\\/cm2. The neutron spectra were observed at 55 and 90 to the rear target normal. The neutron emission was

  3. Faster-than-light EMP source initiated by short X-ray pulse of laser plasma

    Microsoft Academic Search

    Alexander V. Bessarab; Alexander A. Gorbunov; Sergey P. Martynenko; Nikolay A. Prudkoy

    2004-01-01

    The effect which manifests itself in the form of directed electromagnetic pulses initiated by an X-ray incident obliquely on the conducting surface has been confirmed and investigated experimentally in detail. The existence of the above-mentioned phenomenon was predicted more than 25 years ago. So, experimentally, a planar accelerating diode comprising a metallic cathode and grid anode was initiated by an

  4. IR-Assisted Discharge Initiation in Pulsed Plasma Thrusters James E. Cooley

    E-print Network

    Choueiri, Edgar

    as a method of dis- charge initiation. Spark plugs have high erosion rates which limit their lifetime2 was introduced by Berkery and Choueiri.1 The motivation is to explore a possi- ble replacement for spark plugs's backplate. The technique has the po- tential for achieving uniform and erosion-free discharge initiation

  5. Development of a gas-based spectral filter for carbon dioxide laser produced plasma extreme ultraviolet sources

    NASA Astrophysics Data System (ADS)

    Mbanaso, Chimaobi

    Currently, extreme ultraviolet (EUV) lithography is a promising next generation lithography technique for enabling the scaling of device features beyond 22 nm. Out-of-band radiation in EUV exposure tools remains one of the critical issues that must be addressed before the implementation of this lithography technique for high volume manufacturing. Laser produced plasmas which use a carbon dioxide (CO2) drive laser pulse are more likely to be used to generate EUV radiation because of their scalability to higher source power. The out-of-band spectrum at the intermediate focus of EUV sources that use a CO2 laser produced plasma is dominated by scattered radiation from the drive laser which operates near 10.6 microm wavelength. The unmitigated infrared radiation causes deformation of the optics in the lithography scanner making it difficult to maintain stringent overlay specifications. EUV transmission losses incurred as a result of using existing solid filters is of concern due to the limited source power currently achievable in these exposure tools. This research work investigated the use of infrared absorbing gaseous species to spectrally reduce the unwanted CO2 laser light reaching the intermediate focus. The spectral attractiveness of an infrared absorbing gas, sulfur hexafluoride, was evaluated based on the measured absorption cross section at wavelengths around 13.5 nm and 10.6 mum in custom optical systems. Based on the results acquired from the built systems, it was possible to predict the suppression of infrared radiation near 10.6 mum wavelength as well as the EUV transmission losses as a function of different gas densities. As part of this work, gas-based diffusion barriers were considered for inhibiting the molecular transport of the infrared absorbing species to other regions of the EUV system. An experimental configuration equipped with a quadruple mass spectrometer was designed to characterize and test the functionality of a magnetically confined plasma discharge to inhibit gaseous transport. The results indicated ionization and directional molecular collisions as factors that contribute towards establishing a gas density gradient due to the presence of an argon plasma discharge.

  6. Measurements of the optical emission produced during the laboratory beam plasma discharge

    NASA Technical Reports Server (NTRS)

    Hallinan, T. J.; Leinbach, H.; Mantjoukis, G.; Bernstein, W.

    1984-01-01

    Optical observations of a beam-plasma discharge (BPD) in the laboratory showed that the discharge remained confined to a diameter little more than double that of the beam for injection parallel to the magnetic field and approximately equal to that of the beam for injection at large pitch angles. The diameter was independent of beam current but varied linearly with beam velocity and inversely with magnetic field strength. The ionization rate inferred from the total emission of 3914 A, integrated over the radial extent of the beam, was proportional to the excess beam current above that requied for BPD ignition. The proportionality constant ( 12 + or - 2) x 10 to the 14th ions/cm s A was valid over a wide range of pressure and of magnetic field strength. Power loss to ionization in a 20 m path was estimated at up to 4 percent of the beam power. Evidence is presented for effective confinement of suprathermal electrons (parallel to B) by some unidentified process other than electrostatic confinement.

  7. Initial design of a 1 megawatt average, 150 kilovolt pulse modulator for an industrial plasma source ion implantation processor

    SciTech Connect

    Reass, W.A. [Los Alamos National Lab., NM (United States); Deb, D. [Litton Electron Devices, San Carlos, CA (United States)

    1994-07-01

    Plasma Source Ion Implantation (PSII) is a materials surface modification process which can be used to improve performance characteristics of manufacturing tooling and products. Since improvements can be realized in surface hardness, reduced friction, wear, galling, and increased resistance to corrosion, PSII is applicable to a broad spectrum of manufactured items. In PSII, the object to be implanted is placed in a weakly ionized plasma and pulsed to a high negative voltage. The plasma ions are accelerated into the object`s surface, thereby changing its` chemical and physical composition. The plasma dynamic load impedance is highly variable, dependent on implant object area, plasma density, and material composition. The modulator load impedance may be a few tens of ohms and a few thousand picofarads early in time. Late in time, the load may appear as 20,000 Ohms and 100 picofarads. The modulator system must accommodate any process changes, in addition to (frequent) initial ``start-up`` object arcs (from impurities). To implant the required ion densities in a minimum of time, multi-kilohertz rep-rates are often required. An evolutionary design approach was utilized to design a cost-effective and reliable modulator system with components of established performance, suitable for a manufacturing environment. This paper, in addition to presenting the anticipated modulator design required for the PSII application, will review similar modulator topologies and determine operational lifetime characteristics. Further improvements in system electrical efficiency can also be realized with incremental design modifications to the high voltage switch tubes. Development options for upgraded switch tubes of higher efficiency will also be presented.

  8. High Amount Cluster Incorporation in Initial Si Film Deposition by SiH4 Plasma Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Kim, Yeonwon; Hatozaki, Kosuke; Hashimoto, Yuji; Uchida, Giichiro; Kamataki, Kunihiro; Itagaki, Naho; Seo, Hyunwoong; Koga, Kazunori; Shiratani, Masaharu

    2013-01-01

    We have carried out in-situ measurements of Si cluster volume fraction in Si films during plasma chemical vapor deposition by using quartz crystal microbalances (QCM's) together with a cluster-eliminating filter. The cluster volume fraction in films is deduced from film deposition rates with and without Si clusters using QCM's. By employing this method we have revealed a depth profile of the Si cluster volume fraction. A high cluster volume fraction is observed in the initial phase of film deposition. This behavior is compared with time evolution of SiH*, Si* emission intensities and their intensity ratio.

  9. Enhancing the energy of terahertz radiation from plasma produced by intense femtosecond laser pulses

    SciTech Connect

    Jahangiri, Fazel [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan) [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan); Laser and Plasma Research Institute, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Hashida, Masaki; Tokita, Shigeki; Sakabe, Shuji [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan) [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan); Department of Physics, GSS, Kyoto University, Kyoto (Japan); Nagashima, Takeshi; Hangyo, Masanori [Department of Physics, GSS, Kyoto University, Kyoto (Japan) [Department of Physics, GSS, Kyoto University, Kyoto (Japan); Institute of Laser Engineering, Osaka University, Osaka (Japan)

    2013-05-13

    Terahertz (THz) radiation from atomic clusters illuminated by intense femtosecond laser pulses is investigated. By studying the angular distribution, polarization properties and energy dependence of THz waves, we aim to obtain a proper understanding of the mechanism of THz generation. The properties of THz waves measured in this study differ from those predicted by previously proposed mechanisms. To interpret these properties qualitatively, we propose that the radiation is generated by time-varying quadrupoles, which are produced by the ponderomotive force of the laser pulse.

  10. Initial characterization of electron cyclotron heated plasmas in the Columbia Non-Neutral Torus

    NASA Astrophysics Data System (ADS)

    Hammond, Kenneth; Volpe, Francesco; Lazerson, Samuel

    2014-10-01

    The Columbia Non-Neutral Torus (CNT) is a stellarator at Columbia University recently modified for the study of quasi-neutral plasmas heated by 2.45 GHz electron cyclotron waves. Using a simple configuration of four circular planar coils, it generates magnetic surfaces with the lowest aspect ratios (1.9-2.7) ever attained by a stellarator. The low magnetic field (0.09 T), combined with the possibility of electron Bernstein wave heating above the cutoff density, could make CNT suitable for research of magnetohydrodynamic equilibrium and stability at high beta. Additional plans for future work include novel microwave and magnetic diagnostics, heating with electron cyclotron and helicon waves, and error field studies. Here we present an experimental characterization of the parameters of CNT's first microwave-heated plasmas. We present Langmuir probe measurements of temperature and density profiles, fast camera images, and equilibrium reconstructions computed by the VMEC code.

  11. Stable dense plasma jets produced at laser power densities around 10{sup 14} W/cm{sup 2}

    SciTech Connect

    Kasperczuk, A.; Pisarczyk, T.; Borodziuk, S.; Ullschmied, J.; Krousky, E.; Masek, K.; Rohlena, K.; Skala, J.; Hora, H. [Institute of Plasma Physics and Laser Microfusion, 23 Hery St., 00-908 Warsaw (Poland); Institute of Plasma Physics AS CR, Za Slovankou 3, 182 00 Prague 8 (Czech Republic); Institute of Physics AS CR, Na Slovance 2, 182 21 Prague 8 (Czech Republic); Department of Theoretical Physics, University of New South Wales, Sydney (Australia)

    2006-06-15

    The results of investigations are presented that are connected with defocused laser beam-planar target interaction. Following the very large focus laser-plasma interaction experiments on the Nova [H. T. Powell, J. A. Caird, J. E. Murray, and C. E. Thompson, 1991 ICF Annual Report UCRL-LR-105820-91, p. 163 (1991)] and GEKKO-XII [C. Yamanaka, Y. Kato, Y. Izawa, K. Yoshida, T. Yamanaka, T. Sasaki, T. Nakatsuka, J. Kuroda, and S. Nakai, IEEE J. Quantum Electron. QE-17, 1639 (1981)] lasers, as well as on the National Ignition Facility (NIF) laser [W. J. Hogan, E. I. Moses, B. E. Warner, M. S. Sorem, and J. M. Soures, Nucl. Fusion 41, 567 (2001)] with generation of high Mach number jets, this paper is devoted to similar jet generation with very detailed measurements of density profiles by using high-power lasers at large focus conditions. The experiment was carried out with target materials of different mass densities (Al, Cu, Ag, Ta, and Pb) using the Prague Asterix Laser System (PALS) iodine laser [K. Jungwirth, A. Cejnarova, L. Juha, B. Kralikowa, J. Krasa, E. Krousky, P. Krupickova, L. Laska, K. Masek, A. Prag, O. Renner, K. Rohlena, B. Rus, J. Skala, P. Straka, and J. Ullschmied, Phys. Plasmas 8, 2495 (2001)]. The investigations were conducted for the laser radiation energy of 100 J at two wavelengths of 1.315 and 0.438 {mu}m (the first and third harmonics of laser radiation), pulse duration of 0.4 ns, and a focal spot radius of 300 {mu}m. Most of the experimental data were obtained by means of a three-frame laser interferometer and an x-ray streak camera; the crater parameters were obtained by using the crater replica technique. These investigations have shown that stable dense plasma jets can be produced in a simple configuration of laser beam-planar target interaction, provided that a proper target material is used.

  12. Quantitative measurement of hard x-ray spectra for high intensity laser produced plasma

    SciTech Connect

    Zhang, Z.; Nishimura, H.; Namimoto, T.; Fujioka, S.; Arikawa, Y.; Hosoda, H.; Azechi, H. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Nishikino, M.; Kawachi, T.; Sagisaka, A.; Orimo, S.; Ogura, K.; Pirozhkov, A.; Yogo, A.; Kiriyama, H.; Kondo, K. [Quantum Beam Science Directorate, Kansai Photon Science Institute, JAEA, Kyoto 619-0215 (Japan); Okano, Y. [Laser Research Center for Molecular Science, Institute for Molecular Science, National Institute of Natural Science 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585 (Japan); Ohshima, S. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Pioneering Research Unit for Next Generation, Kyoto University, Uji 611-0011 (Japan)

    2012-05-15

    X-ray line spectra ranging from 17 to 77 keV were quantitatively measured with a Laue spectrometer, composed of a cylindrically curved crystal and a detector. Either a visible CCD detector coupled with a CsI phosphor screen or an imaging plate can be chosen, depending on the signal intensities and exposure times. The absolute sensitivity of the spectrometer system was calibrated using pre-characterized laser-produced x-ray sources and radioisotopes. The integrated reflectivity for the crystal is in good agreement with predictions by an open code for x-ray diffraction. The energy transfer efficiency from incident laser beams to hot electrons, as the energy transfer agency for specific x-ray line emissions, is derived as a consequence of this work.

  13. Observation of neutron spectrum produced by fast deuterons via ultraintense laser plasma interactions.

    PubMed

    Izumi, N; Sentoku, Y; Habara, H; Takahashi, K; Ohtani, F; Sonomoto, T; Kodama, R; Norimatsu, T; Fujita, H; Kitagawa, Y; Mima, K; Tanaka, K A; Yamanaka, T

    2002-03-01

    We report the first precise spectral measurement of fast neutrons produced in a deuterated plastic target irradiated by an ultraintense sub-picosecond laser pulse. The 500-fs, 50-J, 1054-nm laser pulse was focused on the deuterated polystyrene target with an intensity of 2 x 10(19) W/cm(2). The neutron spectra were observed at 55 degrees and 90 degrees to the rear target normal. The neutron emission was 7 x 10(4) per steradian for each detector. The observed neutron spectra prove the acceleration of deuterons and neutron production by d(d,n)3He reactions in the target. The neutron spectra were compared with Monte Carlo simulation results and the deuteron's directional anisotropy and energy spectrum were studied. We conclude that 2% of the laser energy was converted to deuterons, which has an energy range of 30 keV up to 3 MeV. PMID:11909268

  14. XPS study of surface chemistry of tungsten carbides nanopowders produced through DC thermal plasma/hydrogen annealing process

    NASA Astrophysics Data System (ADS)

    Krasovskii, Pavel V.; Malinovskaya, Olga S.; Samokhin, Andrey V.; Blagoveshchenskiy, Yury V.; Kazakov, Valery ?.; Ashmarin, Artem ?.

    2015-06-01

    X-ray photoelectron spectroscopy (XPS) has been employed to characterize the surface composition and bonding of the tungsten carbides nanopowders produced through a DC thermal plasma/hydrogen annealing process. The XPS results were complemented with those from Raman spectroscopy, high-resolution transmission electron microscopy, and evolved gas analysis. The products of the DC plasma synthesis are the high-surface-area multicarbide mixtures composed mainly of crystalline WC1-x and W2C. The materials are contaminated with a pyrolitic carbonaceous deposit which forms ?1 nm thick graphitic overlayers on the nanoparticles' surface. The underlying carbides are not oxidized in ambient air, and show no interfacial compounds underneath the graphitic overlayers. When annealed in hydrogen, the multicarbide mixtures undergo transformation into the single-phase WC nanopowders with an average particle size of 50-60 nm. The surface of the passivated and air-exposed WC nanopowders is stabilized by an ultrathin, no more than 0.5 nm in thickness, chemically heterogeneous overlayer, involving graphitic, carbon-to-oxygen, and WO3 bonding. Oxygen presents at coverages above a monolayer preferentially in the bonding configurations with carbon. The surface segregations of carbon are normally observed, even when the bulk content of carbon is below the stoichiometric level.

  15. Numerical modeling of radiation physics in kinetic plasmas [IV] - Isochoric heating by intense X-ray laser-produced photoelectrons

    NASA Astrophysics Data System (ADS)

    Royle, Ryan; Sentoku, Yasuhiko

    2014-10-01

    An intense, hard X-ray laser such as an XFEL is an attractive light source since it can directly heat solid matter isochorically to a temperature of millions of degrees on a time scale of a few tens of femtoseconds, which is much shorter than the plasma expansion time scale. The X-ray laser interaction with carbon, aluminum, silicon, and copper is studied with a particle-in-cell code that solves the photoionization and X-ray transport self-consistently. Photoionization is the dominant absorption mechanism and non-thermal photoelectrons are produced with energy near the X-ray photon energy. The photoelectrons' stopping range is a few microns and they are quickly thermalized in tens of femtoseconds. As a result, a hot plasma column is formed behind the laser pulse with a temperature of more than 100,000 kelvin (>10 eV) and energy density greater than 1011 J/m3. The heating depth and temperature depend on the material and are also controllable by changing the photon energy of the incident laser light.

  16. Directed transfer of microwave radiation in sliding-mode plasma waveguides produced by ultraviolet laser in atmospheric air.

    PubMed

    Zvorykin, Vladimir D; Ionin, Andrei A; Levchenko, Alexei O; Seleznev, Leonid V; Sinitsyn, Dmitrii V; Smetanin, Igor' V; Ustinovskii, Nikolai N; Shutov, Alexei V

    2014-11-01

    Experiments have been performed at hybrid Ti:sapphire/KrF laser facility GARPUN-MTW to develop a novel technique to create a hollow-core sliding-mode plasma-filament waveguide for directed transfer of microwave radiation. Efficient multiphoton air ionization was produced by a train of picosecond 1-TW UV pulses at 248nm wavelength, or by amplitude-modulated 100ns pulse combining a short-pulse train with a free-running 1-GW pulse, which detached electrons off O2- ions. Multiple filamentation of UV laser radiation in air was observed, and filamentation theory based on resonance-enhanced ionization was developed to explain the experimental results. PMID:25402935

  17. Temporal and spectral dependence of samariuom x-ray emission in subpicosecond and nanosecond laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Chenais-Popovics, Claude J.; Audebert, Patrick; Fajardo, M.; Shepherd, Ronnie L.; Peyrusse, Olivier; Gauthier, Jean-Claude J.

    2001-11-01

    Ultra-short x-ray sources are generated by focusing sub- picosecond lasers on massive targets. The emission duration of a samarium x-ray source produced with a 100 TW sub- picosecond laser was measured using an ultra-fast X-ray streak camera. The spectral range was limited around 7.5-8.5 angstrom, the range in which samarium can be used as a backlighter for K(alpha) aluminum absorption experiments. The spectral time-evolution and the duration of samarium emission were measured. Preliminary calculations performed with non-local-thermodynamic equilibrium atomic physics show the plasma cooling which occurs with a characteristic time longer than predicted by radiative hydrocode simulations.

  18. Characterization of short pulse laser-produced plasmas at the Lawrence Livermore National Laboratory ultra short-pulse laser

    SciTech Connect

    Shepherd, R.; Price, D.; White, W.; Osterheld, A.; Walling, R.; Goldstein, W.; Stewart, R. [Lawrence Livermore National Lab., CA (US); Gordan, S. [Univ. of California, Berkeley, CA (US). Physics Dept.

    1993-07-14

    The K-shell emission from porous aluminum targets is used to infer the density and temperature of plasmas created with 800 nm and 400 nm, 140 fs laser light. The laser beam is focused to a minimum spot size of 5 {mu}m with 800 nm light and 3 {mu}m with 400 nm light, producing a normal incidence peak intensity of 10{sup 18} Watts/cm{sup 2}. A new 800 fs x-ray streak camera is used to study the broadband x-ray emission. The time resolved and time integrated x-ray emission implies substantial differences between the porous target and the flat target temperature.

  19. Effects of the dynamics of droplet-based laser-produced plasma on angular extreme ultraviolet emission profile

    SciTech Connect

    Giovannini, Andrea Z.; Abhari, Reza S. [Laboratory for Energy Conversion, ETH Zurich, 8092 Zurich (Switzerland)

    2014-05-12

    The emission distribution of extreme ultraviolet (EUV) radiation from droplet targets is dependent on the dynamics of the laser-produced plasma. The EUV emission is measured on a 2% bandwidth centered at 13.5?nm (in-band). The targets of the laser are small (sub-50 ?m) tin droplets, and the in-band emission distribution is measured for different laser irradiances and droplet sizes at various angular positions. Larger droplets lead to a faster decay of EUV emission at larger angles with respect to the laser axis. A decrease in laser irradiance has the opposite effect. The measurements are used together with an analytical model to estimate plume dynamics. Additionally, the model is used to estimate EUV emission distribution for a desired droplet diameter and laser irradiance.

  20. Stigmatic spectrograph with a 2-D CCD detector for soft x-ray observations of laser produced plasmas

    NASA Astrophysics Data System (ADS)

    Villoresi, P.; Nicolosi, P.

    1994-06-01

    A stigmatic XUV spectrometer with a bidimensional intensified CCD, for performing spectroscopic observations of laser produced plasma (LPP) with high spectral and spatial resolution is discussed. The spectrometer adopted the grazing incidence Rowland mount, with spherical grating, combined with a toroidal mirror to fill the entrance pupils and to rectify the astigmatism. The detector was comprised of a scintillator in the focal plane coupled with an intensified outside the vacuum chamber. To demonstrate the performance of the instrument with this new detection approach, spectroscopic observations of LPPs of various elements were taken. The results showed the capacity to observe small source with high spectral and spatial resolution integrated with high sensitivity. The PC based acquisition presented ease of operation and real-time display and evaluation of the spectra. The examples of Be, BN, and W LPPs observations led to the assumption that this method was extremely powerful and constituted a step beyond both photodiode arrays and photographic film detection.

  1. Plasma Channels for Electron Accelerators Using Discharges in Structured Gas Cells

    Microsoft Academic Search

    Rodolfo A. Bendoyro; Roxana I. Onofrei; Joo Sampaio; Rita Macedo; Gonalo Figueira; Nelson C. Lopes

    2008-01-01

    We present a new scheme to produce preformed plasma waveguides to extend the acceleration length of laser-plasma accelerators. The plasma is produced in a hydrogen background by a high-voltage discharge between two hollow conic electrodes through a sequence of thin dielectric plates with apertures that fix the initial plasma diameter and position. The thickness of the dielectric plates is close

  2. Initial Results of DC Electric Fields, Associated Plasma Drifts, Magnetic Fields, and Plasma Waves Observed on the C/NOFS Satellite

    NASA Technical Reports Server (NTRS)

    Pfaff, R.; Freudenreich, H.; Bromund, K.; Klenzing, J.; Rowland, D.; Maynard, N.

    2010-01-01

    Initial results are presented from the Vector Electric Field Investigation (VEFI) on the Air Force Communication/Navigation Outage Forecasting System (C/NOFS) satellite, a mission designed to understand, model, and forecast the presence of equatorial ionospheric irregularities. The VEFI instrument includes a vector DC electric field detector, a fixed-bias Langmuir probe operating in the ion saturation regime, a flux gate magnetometer, an optical lightning detector, and associated electronics including a burst memory. Compared to data obtained during more active solar conditions, the ambient DC electric fields and their associated E x B drifts are variable and somewhat weak, typically < 1 mV/m. Although average drift directions show similarities to those previously reported, eastward/outward during day and westward/downward at night, this pattern varies significantly with longitude and is not always present. Daytime vertical drifts near the magnetic equator are largest after sunrise, with smaller average velocities after noon. Little or no pre-reversal enhancement in the vertical drift near sunset is observed, attributable to the solar minimum conditions creating a much reduced neutral dynamo at the satellite altitude. The nighttime ionosphere is characterized by larger amplitude, structured electric fields, even where the plasma density appears nearly quiescent. Data from successive orbits reveal that the vertical drifts and plasma density are both clearly organized with longitude. The spread-F density depletions and corresponding electric fields that have been detected thus far have displayed a preponderance to appear between midnight and dawn. Associated with the narrow plasma depletions that are detected are broad spectra of electric field and plasma density irregularities for which a full vector set of measurements is available for detailed study. Finally, the data set includes a wide range of ELF/VLF/HF oscillations corresponding to a variety of plasma waves, in particular banded ELF hiss, whistlers, and lower hybrid wave turbulence triggered by lightning-induced sferics. The VEFI data represents a new set of measurements that are germane to numerous fundamental aspects of the electrodynamics and irregularities inherent to the Earth's low latitude ionosphere.

  3. Characterization and study of the thermodynamic equilibrium departure of an argon plasma flame produced by a surface-wave sustained discharge

    NASA Astrophysics Data System (ADS)

    Calzada, M. D.; Sez, M.; Garca, M. C.

    2000-07-01

    Surface wave induced plasma (SWP) is a particular class of microwave induced plasma. It is used in atomic emission and mass spectrometry as a source of excitation for the elemental analysis of samples in analytical chemistry. This discharge is mainly used at powers less than 300 W. At such low power, an efficient process of desolvation, atomization, excitation and ionization of the analyte can only be reached provided the density of power absorbed in the discharge is large. This requires a plasma whose volume increases very little with increasing absorbed power. At atmospheric pressure in the SWP, such a volume limitation can be achieved by having the plasma extending into ambient air in the form of a flame (open air discharge). This article presents the results of the experimental characterization and study of the degree of thermodynamic equilibrium of an argon plasma flame produced by a surfatron. The values of the plasma parameters and b(p) (departure from equilibrium) parameter for the ArI levels show that the discharge is a two-temperature plasma. By comparing the results with those obtained for a classical surface-wave plasma column, it can be concluded that the plasma in flame is more suited to be used as a source of excitation in analytical chemistry, due to its higher electronic density and temperatures values.

  4. Techniques And Initial Results From An X-Ray Laser Experiment Using Laser-Vaporized Copper Foil Plasmas

    NASA Astrophysics Data System (ADS)

    Molander, W. A.; Lee, T. N.; Ford, J. L.; Elton, R. C.

    1986-10-01

    A series of exploratory experiments recently carried out at NRL were directed towards the possible utilization of laser-heated ultra-thin copper films for generating elongated plasmas of sufficient uniformity to produce amplification on 3s-3p transitions in neon-like copper ions. The NRL Pharos III laser operating at 140-335 J in 2-6 ns pulses was used as a driver. Variations were made in the plasma length, the laser energy and pulse shape, and the copper thickness in order to optimize the gain-medium conditions. A primary necessity was to assure on each attempt an accurately-aligned vuv grazing-incidence spectrograph. Using space-resolved x-ray crystal spectroscopy and pinhole photography as auxiliary diagnostics, axial homogeneity as well as front/rear symmetry were measured. The electron temperature in the Cu XX plasma, as estimated from intensity ratios of 2p-nd transition x-ray lines, was found to increase with copper thickness. Various explanations for the lack of measureable gain in these inital tests are discussed. A novel slotted copper foil (thicker) target design was also tested and showed similar characteristics to the thin copper film targets. Also, spectral features from a selenium target exposure are described.

  5. Low-debris, efficient laser-produced plasma extreme ultraviolet source by use of a regenerative liquid microjet target containing tin dioxide (SnO{sub 2}) nanoparticles

    SciTech Connect

    Higashiguchi, Takeshi; Dojyo, Naoto; Hamada, Masaya; Sasaki, Wataru; Kubodera, Shoichi [Department of Electrical and Electronic Engineering and Photon Science Center, University of Miyazaki, Gakuen Kibanadai Nishi 1-1, Miyazaki, Miyazaki 889-2192 (Japan)

    2006-05-15

    We demonstrated a low-debris, efficient laser-produced plasma extreme ultraviolet (EUV) source by use of a regenerative liquid microjet target containing tin-dioxide (SnO{sub 2}) nanoparticles. By using a low SnO{sub 2} concentration (6%) solution and dual laser pulses for the plasma control, we observed the EUV conversion efficiency of 1.2% with undetectable debris.

  6. Mutation breeding of extracellular polysaccharide-producing microalga Crypthecodinium cohnii by a novel mutagenesis with atmospheric and room temperature plasma.

    PubMed

    Liu, Bin; Sun, Zheng; Ma, Xiaonian; Yang, Bo; Jiang, Yue; Wei, Dong; Chen, Feng

    2015-01-01

    Extracellular polysaccharides (EPS) produced by marine microalgae have the potential to be used as antioxidants, antiviral agents, immunomodulators, and anti-inflammatory agents. Although the marine microalga Crypthecodinium cohnii releases EPS during the process of docosahexaenoic acid (DHA) production, the yield of EPS remains relatively low. To improve the EPS production, a novel mutagenesis of C. cohnii was conducted by atmospheric and room temperature plasma (ARTP). Of the 12 mutants obtained, 10 mutants exhibited significantly enhanced EPS yield on biomass as compared with the wild type strain. Among them, mutant M7 was the best as it could produce an EPS volumetric yield of 1.02 g/L, EPS yield on biomass of 0.39 g/g and EPS yield on glucose of 94 mg/g, which were 33.85%, 85.35% and 57.17% higher than that of the wild type strain, respectively. Results of the present study indicated that mutagenesis of the marine microalga C. cohnii by ARTP was highly effective leading to the high-yield production of EPS. PMID:25872142

  7. Pulsed power produced counter-propagating plasma flows and the study of shock wave formation for laboratory astrophysical phenomena

    NASA Astrophysics Data System (ADS)

    Valenzuela, Julio; Collins, Gilbert; Zick, Tom; Narkis, Jeff; Krasheninnikov, Igor; Beg, Farhat

    2014-10-01

    We report on counter-propagating plasma flows produced by two vertically opposing conical wire arrays using a compact current driver capable of producing 250 kA in about 150 ns. Laser interferometry and extreme ultraviolet imaging were performed to study the collision of the jets. A shock formed by jets interaction was clearly observed and remained stationary for at least 50 ns, after this period a bow shock developed propagating downwards at ~20 km/s. Interferometry data showed that the ion density of the jets prior to collision was of the order of 2 1017cm-3 and a jump in density of ~4 was observed at the shock region. A lower limit of ~100 km/s has been measured for the jets velocity. The inter ions mean free path has been estimated to be ~12 mm, which is larger than the shock wave scale ~5 mm, and hence the shock is not mediated by collisions. Magnetic field advection, which can drastically modify the conditions for shock formation, will be discussed. Kinetic particle-in-cell modeling using LSP code has also been implemented and benchmarked against the experimental results. The work was partially funded by the Department of Energy Grant No. DE-SC0001063.

  8. Low-level plasma HIVs in patients on prolonged suppressive highly active antiretroviral therapy are produced mostly by cells other than CD4 T-cells.

    PubMed

    Sahu, Gautam K; Paar, David; Frost, Simon D W; Smith, Melissa M; Weaver, Scott; Cloyd, Miles W

    2009-01-01

    The cellular source(s) and the clinical significance of persistent low-level viremia, below 50 HIV RNA copies per ml of plasma, achieved in many patients with high adherence to highly active antiretroviral therapy (HAART) remain unclear. Also, it is not clear if residual plasma HIVs during HAART can become predominant populations in the rebounding plasma viral loads after therapy interruption. Since, different HIV quasispecies tend to compartmentalize in various cell types and tissue locations in patients during chronic infection, the phylogenetic relationships between HIV sequences amplified from residual plasma viruses and CD4 T cells of five patients on long-term suppressive therapy were examined. Three of these patients stopped therapy voluntarily for 3 weeks, but only one of them demonstrated viral load rebound in plasma. In phylogenetic analyses, the residual plasma viruses were found to be distinct genetically from the majority of CD4 T cell-associated virus populations in four of five patients. The compartmental analyses revealed that in all patients, plasma- and CD4 T cell-derived viral sequences were compartmentalized separately. Interestingly, the plasma sequences obtained before and after HAART-off in two patients were produced apparently from the same compartment, which was different from the circulating CD4 T cell-compartment. These results suggest the possibility that residual plasma viruses in patients on long-term suppressive HAART may be produced persistently from a cellular source yet to be identified, and are capable of spreading quickly in vivo, accounting for the rapid rebound of viral loads in plasma after therapy interruption. PMID:19031450

  9. Influence of ablated and tunneled electrons on quasi-phase-matched high-order-harmonic generation in laser-produced plasma

    NASA Astrophysics Data System (ADS)

    Ganeev, Rashid A.; To?a, Valer; Kovcs, Katalin; Suzuki, Masayuki; Yoneya, Shin; Kuroda, Hiroto

    2015-04-01

    Studies of the quasi-phase-matched harmonics generated in spatially modulated silver plasma are presented. We analyze the influence of the driving and heating pulse energies on the enhancement and spectral tuning of the quasi-phase-matched harmonics and show the tuning of those enhanced groups of harmonics by tilting the multislit mask placed in front of the ablated targets. Calculations performed in the laser-produced plasmas demonstrate the joint influence of the electrons that appeared during target ablation and tunnel ionization on the tuning of the quasi-phase-matching conditions in the plasmas.

  10. Interaction of Cu and plastic plasmas as a method of forming laser produced Cu plasma streams with a narrow jet or pipe geometry

    SciTech Connect

    Kasperczuk, A.; Pisarczyk, T.; Chodukowski, T.; Kalinowska, Z.; Parys, P. [Institute of Plasma Physics and Laser Microfusion, 23 Hery St., 00-908 Warsaw (Poland); Ullschmied, J. [Institute of Plasma Physics ASCR, v.v.i., Za Slovankou 3, 182 00 Prague 8 (Czech Republic); Krousky, E.; Pfeifer, M.; Skala, J. [Institute of Physics ASCR, v.v.i., Na Slovance 2, 182 21 Prague 8 (Czech Republic); Klir, D.; Kravarik, J.; Kubes, P.; Rezac, K. [Czech Technical University in Prague, Faculty of Electrical Engineering (FEE), Prague (Czech Republic); Pisarczyk, P. [Warsaw University of Technology, Institute of Computer Sciences (ICS), 15/19 Nowowiejska St., 00-665 Warsaw (Poland)

    2011-04-15

    This brief communication is aimed at investigations of interaction of axially symmetrical light (plastic) plasma with heavy (copper) plasma. The use of axially symmetrical target compositions consisting of materials with low and high atomic numbers makes it possible to create different plasma stream configurations (e.g., very narrow jet or pipe). In the paper certain their applications are suggested.

  11. Fundamentals of Discharge Initiation in Gas-Fed Pulsed Plasma Thrusters

    E-print Network

    Choueiri, Edgar

    of producing uniform current sheets reliably for the entire required lifetime of a thruster on a space mission Engineering Department, cooley@princeton.edu. Chief Scientist, EPPDyL. Associate Professor, Mechanical and Aerospace Engineering Department. Associated Faculty, PPPL. choueiri@princeton.edu. 1 The 29th International

  12. Plasma-controlled metal catalyst saturation and the initial stage of carbon nanostructure array growth

    SciTech Connect

    Levchenko, I. [Plasma Nanoscience, School of Physics, University of Sydney, Sydney NSW 2006 (Australia); Ostrikov, K. [CSIRO Materials Science and Engineering, P. O. Box 218, Lindfield NSW 2070 (Australia); Plasma Nanoscience, School of Physics, University of Sydney, Sydney NSW 2006 (Australia); Mariotti, D. [Department of Microelectronic Engineering, Rochester Institute of Technology, Rochester, New York 14623 (United States); Murphy, A. B. [CSIRO Materials Science and Engineering, P. O. Box 218, Lindfield NSW 2070 (Australia)

    2008-10-01

    The kinetics of the nucleation and growth of carbon nanotube and nanocone arrays on Ni catalyst nanoparticles on a silicon surface exposed to a low-temperature plasma are investigated numerically, using a complex model that includes surface diffusion and ion motion equations. It is found that the degree of ionization of the carbon flux strongly affects the kinetics of nanotube and nanocone nucleation on partially saturated catalyst patterns. The use of highly ionized carbon flux allows formation of a nanotube array with a very narrow height distribution of half-width 7 nm. Similar results are obtained for carbon nanocone arrays, with an even narrower height distribution, using a highly ionized carbon flux. As the deposition time increases, nanostructure arrays develop without widening the height distribution when the flux ionization degree is high, in contrast to the fairly broad nanostructure height distributions obtained when the degree of ionization is low.

  13. Ignitor plug erosion and arc initiation processes in a one-millipound pulsed plasma thruster

    NASA Technical Reports Server (NTRS)

    Aston, G.; Pless, L. C.

    1981-01-01

    The results are presented of a one-millipound pulsed plasma ignition system study. The preliminary data indicate that inductively coupling the ignition plug cathode to the thruster cathode is more beneficial to ignitor plug longevity than resistive coupling. These benefits arise from the ability of the coupling conductor to control the build-up of a carbonaceous deposit on the plug face. The deposit build-up is a strong function of the peak coupling current experienced during thruster operation. The relationship between the ignitor plug discharge and thruster discharge is shown to be very complex with equivalent circuit elements which are dynamic in nature. A preliminary representation of this equivalent circuit is developed.

  14. Joint Experiments on X-ray/Particle Emission from Plasmas Produced by Laser Irradiating Nano Structured Targets

    SciTech Connect

    Hegazy, H.; Diab, F. [Plasma Physics Dept., NRC, EAEA, 13759 Enshass (Egypt); Allam, S. H.; El-Sherbini, Th. M.; Abd El-Latif, G.; Farrag, A.; Helal, A.; Refaie, A.; Sharkawy, H. [Physics Dept., Faculty of Science, Cairo University, Giza (Egypt); Chaurasia, S.; Dhareshwar, L. [3Laser and Neutron Physics Section, Bhabha Atomic Research Centre, Mumbai (India); Kunze, H.-J. [Institut fuer Exp.physik V, Ruhr-Universitaet Bochum, 44780 Bochum (Germany); Mank, G. [IAEA, NAPC Physics Section, Vienna (Austria); McDaniel, D. H. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185-1178 (United States); Rosinski, M.; Ryc, L.; Wolowski, J. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Stewart, B. [ICTP, Trieste (Italy); Abd El-Ghany, H. [9Physics Dept., Faculty of Engineering, Banha University (Egypt); Abd El-Rahim, F. M. [Physics Dept., Faculty of Science, Al-Azhar University, Assuit Branch, Assuit (Egypt)] (and others)

    2008-04-07

    The 1st Joint (Host Laboratory) Experiment on laser plasma involving more than twenty scientists from eight countries has been carried out at the Laser and New Materials Laboratory, Faculty of Science, Cairo University, Egypt. It was co-ordinated by the International Atomic Energy Agency (IAEA) and supported through the IAEA and the ICTP (International Centre for Theoretical Physics, Trieste). The main experimental programme was aimed at characterising the possible enhancement of x-ray and particle emission from plasmas produced by laser incidence on nano-structured targets. Laser beams at 1.064 {mu}m of 250 mJ and 532 nm of 165 mJ focused at the target surface using a nanosecond laser type Quantel were used in the present study. In the present experiments nano-copper structures evaporated onto copper bulk disks and nano-gold structures evaporated onto gold ones were used. The thickness of the nano-materials on their bulk material was 1 {mu}m. An ion collector and x-ray semiconductor diode were used to study the ion and x-ray emission, respectively. Both were positioned at the same port at 90 deg. with respect to the target surface and at 90 cm from the surface in the case of the ion collector and 55 cm in the case of the x-ray detector. These experiments were performed at vacuum pressures of (5--8)x10{sup -6} mbar. Comparison of both studies in the case of nano structured targets and bulk targets were performed at different laser fluencies (1x10{sup 9}-1x10{sup 12} W/cm{sup 2}) on the target. A 20% increase of the X-ray emission for nano gold with respect to bulk gold was observed, however, the x-ray emission in the of nano copper and copper was the same.

  15. Low temperature plasma deposition of silicon nitride to produce ultra-reliable, high performance, low cost Sealed Chip-on-Board (SCOB) assemblies

    Microsoft Academic Search

    Ronald M. Kubacki

    1994-01-01

    Plasma enhanced chemical vapor deposition (PECVD) has existed for many years in the integrated circuit industry and has established itself as a superior method of applying various inorganic coatings to integrated circuitry on silicon wafers. The initial emphasis for developing such a coating was an attempt to find a durable film which could be deposited at a temperature which is

  16. Low temperature plasma deposition of silicon nitride to produce ultra-reliable, high performance, low cost sealed chip-on-board (SCOB) assemblies

    Microsoft Academic Search

    Ronald M. Kubacki

    1995-01-01

    Plasma enhanced chemical vapor deposition (PECVD) has existed for many years in the integrated-circuit industry and has established itself as a superior method of applying various inorganic coatings to integrated circuitry on silicon wafers. The initial emphasis for developing such a coating was an attempt to find a durable film which could be deposited at a temperature which is less

  17. Effect of additive gases on synthesis of organic compounds from carbon dioxide using non-thermal plasma produced by atmospheric surface discharges

    Microsoft Academic Search

    Nobuya Hayashi; Tsutomu Yamakawa; Seiji Baba

    2006-01-01

    Reduction and recycling of carbon dioxide (CO2) were performed using a non-thermal plasma produced by a surface discharge at atmospheric pressure. Useful hydrocarbons (CHs) such as dimethyl ether and methane were produced at the discharge voltage of 11kV, when hydrogen (H2) gas was mixed with CO2 and the mixture ratio was 50%. The conversion of CO2 to the CHs mixing

  18. Efficient multiline nanosecond pulse amplification in planar waveguide CO? amplifier for extreme UV laser-produced plasma source.

    PubMed

    Nowak, Krzysztof M; Ohta, Takeshi; Suganuma, Takashi; Fujimoto, Junichi; Mizoguchi, Hakaru; Sumitani, Akira; Endo, Akira

    2014-04-01

    In this Letter, we report on recent experimental results of a short pulse amplification at 10.6 ?m wavelength required to drive a tin laser-produced plasma (LPP) extreme ultraviolet (UV) source. We report for the first time, to our best knowledge, a highly efficient pulsed amplification in a multipass amplifier built on RF-discharge-excited, diffusion-cooled CO2, planar waveguide industrial CO2 laser. About 2 kW of output average power was obtained from about 100 W input average power in ?15??ns pulses at 100 kHz pulse repetition frequency. As much as 60% relative extraction efficiency, as compared to continuous-wave amplification in similar conditions, and 5.8% wall-plug efficiency was recorded and believed to be the highest reported so far. An improvement of extraction efficiency by ?10% is reported when driving the amplifier with two lines of CO2 regular band in good agreement with expectations. PMID:24686647

  19. Quality Assurance Manual for the "Frutas y Verduras" produce operation: 1. Initial considerations on the evaluaton and conservation of vegetables

    E-print Network

    Riba, Edgard Luis

    1987-01-01

    Abstract This professional paper is the starting point for the development of the Quality Assurance Manual for the produce operation "Frutas y Verduras, " in the Republic of Panama. The paper deals with the main vegetables handled by the Frutas y... description of what the handling practices are at the present time, and also, gives recommendations on what they should be. 2 ALLIUM 2. 1 Bunching onion (Cebollina, Allium fistulosum): 2. 1. 1 Description Bunching onions, as consumed in Panama, do...

  20. Copper, zinc, tin and lead in canned evaporated milk, produced in Lithuania: the initial content and its change at storage

    Microsoft Academic Search

    Danute Terese Ramonaityte

    2001-01-01

    The study has been carried out to elucidate what contents of heavy metals were typical for canned milk productsevaporated (TS 25.528.5%) sterilized milk and condensed sweetened milk, produced in Lithuania in the period 19831997. The influence of storage time upon the level of Sn, Pb, Cu and Zn in the products has also been determined. The results show that the

  1. Milk production correlates negatively with plasma levels of pregnancy-associated glycoprotein (PAG) during the early fetal period in high producing dairy cows with live fetuses

    Microsoft Academic Search

    F. Lpez-Gatius; J. M. Garbayo; P. Santolaria; J Yniz; A. Ayad; N. M. de Sousa; J. F. Beckers

    2007-01-01

    This study was designed to establish possible factors affecting plasma pregnancy-associated glycoprotein (PAG) concentrations during early pregnancy in high producing dairy cows with live fetuses. Blood samples were obtained on days 35, 42, 49, 56 and 63 of gestation from 80 lactating cows in two herds carrying live fetuses. Radioimmunoassay systems were used to determine PAG (RIA-497 and RIA-706) and

  2. Laser induced breakdown spectroscopy of zinc, cadmium and mercury plasma parameters produced by the 1064 nm, 532 nm, and 355 nm OF Nd:YAG laser

    Microsoft Academic Search

    N. M. Shaikh; S. Hafeez; M. A. Baig

    2009-01-01

    Summary form only given. We report the measurements of the zinc, cadmium and mercury plasma parameters produced by the fundamental mode of a Nd:YAG laser. From the spectroscopic analysis of the observed spectral lines we have estimated the excitation temperature and the electron number density using the Boltzmann plots and the Stark broadened profiles of the spectral lines respectively. The

  3. The use of neutral beam heating to produce high performance fusion plasmas, including the injection of tritium beams into the Joint European Torus (JET)

    SciTech Connect

    Thompson, E.; Stork, D.; de Esch, H.P.L. (JET Joint Undertaking, Abingdon, Oxon 0X14 3EA (United Kingdom)); the JET Team

    1993-07-01

    The neutral beam injection (NBI) system of the Joint European Torus (JET) [[ital Plasma] [ital Physics] [ital and] [ital Controlled] [ital Nuclear] [ital Fusion] [ital Research] (International Atomic Energy Agency, Vienna, 1985), Vol. 1, p. 11] has proved to be an extremely effective and flexible heating method capable of producing high performance plasmas and performing a wide range of related physics experiments. High fusion performance deuterium plasmas have been obtained in the hot-ion (HI) H-mode regime, using the central particle fueling and ion heating capabilities of the NBI system in low target density plasmas, and in the pellet enhanced plasma (PEP) H-mode regime, where the good central confinement properties of pellet fueled plasmas are exploited by additional heating and fueling as well as the transition to H mode. The HI H-mode configuration was used for the First Tritium Experiment (FTE) in JET in which NBI was used to heat the plasma using 14 D[sup 0] beams and, for the first time, to inject T[sup 0] using the two remaining beams. These plasmas had a peak fusion power of 1.7 MW from deuterium--tritium (D--T) fusion reactions. The capability for injection of a variety of beam species (H[sup 0], D[sup 0], [sup 3]He[sup 0], and [sup 4]He[sup 0]) has allowed the study of confinement variation with atomic mass and the simulation of [alpha]-particle transport. Additionally, the use of the NBI system has permitted an investigation of the plasma behavior near the toroidal [beta] limit over a wide range of toroidal field strengths.

  4. Study of recombination processes during the expansion phase of titanium-plasma produced by picosecond Nd:glass laser radiation

    NASA Astrophysics Data System (ADS)

    Abd El-Hameed, Afaf M.; Azzouz, I. M.; Abou-Koura, G. H.; Gamal, Yosr E. E.-D.

    2003-05-01

    An investigation of the plasma dynamics during its expansion phase is presented. The analysis is based on a numerical model, which considers the adiabatic plasma expansion as well as a three-body recombination process as the main source for plasma cooling. The result shows that a fast energy transfer between electrons and ions is observed during the early stage of plasma expansion. Three-body recombination process exhibits a pronounced effect leading to a "freezing" feature in the average charge states of heavy particles. This process seems to control the fractional population of ionic species at the end of the expansion phase.

  5. Experiments with Plasmas Produced by Potassium-Seeded Cyanogen Oxygen Flames for Study of Radio Transmission at Simulated Reentry Vehicle Plasma Conditions

    NASA Technical Reports Server (NTRS)

    Huber, Paul W.; Gooderum, Paul B.

    1961-01-01

    A method for the chemical production of an ionized gas stream for application to radio transmission studies is described. Involved is the combustion of gaseous cyanogen and oxygen with the addition of vaporized potassium in some cases to further increase the ionization. Experiments are described in which a 3-inch-diameter subsonic free jet at atmospheric pressure is used, and the results are presented. The plasma obtained by using this method is sufficient to simulate plasma conditions expected for reentering hypersonic vehicles. The unseeded plasma stream temperature is indicated to be about 4,200 K, with the degree of ionization indicated to be that expected from thermal equilibrium considerations. Measurements of radio-signal loss due to the unseeded flame plasma are presented for microwaves of 8 to 20 kmc transmitted through the stream and for a dipole transmitting model of 219.5 mc immersed in the stream. Favorable comparison of these results with the simple plane-wave signal-attenuation theory was obtained. In the case of a 9.4-kmc microwave signal of 30-kw peak power, the preliminary indication is that the plasma characteristics were not changed due to this strong signal. Comparison of a simplified concept of radio-signal attenuation due to plasmas is made with some hypersonic reentry vehicle signal-loss data. Other areas of plasma research using this method for the transmission problem are indicated.

  6. Application of laser-produced extended plasma plumes for generation and characterization of the high-order harmonics of 64 fs pulses

    NASA Astrophysics Data System (ADS)

    Ganeev, Rashid A.; Suzuki, Masayuki; Kuroda, Hiroto

    2014-11-01

    Harmonics with the photon energy of up to ~150 eV were studied using extended ablation plumes as the nonlinear media. The application of the ablation pulses of different duration covering the range between a few tens of femtoseconds and a few tens of nanoseconds revealed the advanced features of the extended plasmas produced by the subnanosecond pulses for efficient harmonic generation. The examples of the quasi-phase-matching of a group of harmonics in the plateau range and the advantages of using the two-color pump and cluster-containing plasmas are presented. We analyze the spatial and coherence characteristics of the high-order harmonics produced during propagation of the 64 fs pulse through the extended plasma plume produced by 370 ps pulses. It is shown that the divergence of plasma harmonics in the plateau range is 7 times smaller than the divergence of the driving radiation used for high-order harmonic generation. The measurements of the coherence properties of the lower-order harmonics showed that the visibility of interference fringes in the far field was in the range of 0.54-0.73.

  7. Patient-centered medical home initiative produced modest economic results for Veterans Health Administration, 2010-12.

    PubMed

    Hebert, Paul L; Liu, Chuan-Fen; Wong, Edwin S; Hernandez, Susan E; Batten, Adam; Lo, Sophie; Lemon, Jaclyn M; Conrad, Douglas A; Grembowski, David; Nelson, Karin; Fihn, Stephan D

    2014-06-01

    In 2010 the Veterans Health Administration (VHA) began a nationwide initiative called Patient Aligned Care Teams (PACT) that reorganized care at all VHA primary care clinics in accordance with the patient-centered medical home model. We analyzed data for fiscal years 2003-12 to assess how trends in health care use and costs changed after the implementation of PACT. We found that PACT was associated with modest increases in primary care visits and with modest decreases in both hospitalizations for ambulatory care-sensitive conditions and outpatient visits with mental health specialists. We estimated that these changes avoided $596 million in costs, compared to the investment in PACT of $774 million, for a potential net loss of $178 million in the study period. Although PACT has not generated a positive return, it is still maturing, and trends in costs and use are favorable. Adopting patient-centered care does not appear to have been a major financial risk for the VHA. PMID:24889947

  8. Optical emission from laser-produced chromium and magnesium plasma under the efiect of two sequential laser pulses

    Microsoft Academic Search

    V N RAI; F Y YUEH; J P SINGH

    Parametric study of optical emission from two successive laser pulses pro- duced chromium and magnesium plasma is presented. The line emission from chromium and magnesium plasma showed an increase by more than six times for double laser pulse excitation than for single-pulse excitation. An optimum increase in emission intensity was noted for inter-pulse delay of 2{3 \\

  9. MULTI-MeV ELECTRONS PRODUCED BY A FEMTOSECOND LASER PULSE PROPAGATING IN AN EXPLODING-FOIL PLASMA

    Microsoft Academic Search

    D. Giulietti; M. Galimberti; A. Giulietti; L. A. Gizzi; R. Numico; P. Tomassini

    Conditions for efficient electron acceleration in the wake of a 35fs laser pulse propagating in an exploding- foil plasma have been achieved. The density of the plasma, pre-formed by the Amplified Spontaneous Emission preceding the fs pulse, was mapped via Nomarski interferometry. A very collimated bunch of energetic electrons has been detected along the laser axis. The accelerated electrons were

  10. A neutral strongly coupled laser-produced plasma by strong-field ionization in a gas jet

    NASA Astrophysics Data System (ADS)

    Bergeson, S. D.; Lyon, M.; Peatross, J. B.; Harrison, N.; Crunkleton, D.; Wilson, J.; Rupper, S.; Diaw, A.; Murillo, M. S.

    2015-06-01

    We report measurements of a neutral strongly coupled plasma generated by focusing a femtosecond-duration laser pulse into a room-temperature gas jet. The ion temperature in this plasma is determined by the plasma density through the disorder-induced heating effect. We present measurements of the mass, radius, and energy dependence of the time-varying ion density as the plasma expands. Molecular dynamics model indicate that higher values of the strong coupling parameter could be achieved if the plasma is ionized again by a second laser pulse that follows the first one. However, the final value of the coupling parameter appears to be only weakly dependent on the final ionization state.

  11. Characterization of Electron Temperature and Density Profiles of Plasmas Produced by Nike KrF Laser for Laser Plasma Instability (LPI) Research

    NASA Astrophysics Data System (ADS)

    Oh, Jaechul; Weaver, J. L.; Phillips, L.; Obenschain, S. P.; Schmitt, A. J.; Kehne, D. M.; Chan, L.-Y.; Serlin, V.

    2011-10-01

    Previous experiments with Nike KrF laser (? = 248 nm , ?? ~ 1 THz) observed LPI signatures near quarter critical density (nc / 4) in CH plasmas, however, detailed measurement of the temperature (Te) and density (ne) profiles was missing. The current Nike LPI campaign will perform experimental determination of the plasma profiles. A side-on grid imaging refractometer (GIR) is the main diagnostic to resolve Te and ne in space taking 2D snapshots of probe laser (? = 266 nm , ?t = 8 psec) beamlets (50 ?m spacing) refracted by the plasma at laser peak time. Ray tracing of the beamlets through hydrodynamically simulated (FASTRAD3D) plasma profiles estimates the refractometer may access densities up to ~ 0 . 2nc . With the measured Te and ne profiles in the plasma corona, we will discuss analysis of light data radiated from the plasmas in spectral ranges relevant to two plasmon decay and convective Raman instabilities. Validity of the (Te ,ne) data will also be discussed for the thermal transport study. Work supported by DoE/NNSA and ONR and performed at NRL.

  12. LC-MS/MS analysis of plasma polyunsaturated fatty acids in type 2 diabetic patients after insulin analog initiation therapy

    PubMed Central

    2013-01-01

    Background Eicosanoids derived from omega-6 (n6) polyunsaturated fatty acids (PUFAs) have proinflammatory functions whereas eicosanoids derived from omega-3 (n3) PUFAs have anti-inflammatory properties. This study was designed to evaluate the effect of insulin analog initiation therapy on n6 and n3 PUFAs in type 2 diabetic patients during early phase. Methods Sixteen type 2 diabetic patients with glycosylated hemoglobin (HbA1c) levels above 10% despite ongoing combination therapy with sulphonylurea and metformin were selected. Former treatment regimen was continued for the first day followed by substitution of sulphonylurea therapy with different insulin analogs (0.4 U/kg/day) plus metformin. Blood samples were obtained from all patients at 24 and 72hours. Plasma levels of arachidonic acid (AA, C20:4n6), dihomo-gamma-linolenic acid (DGLA, C20:3n6), eicosapentaenoic acid (EPA, C20:5n3) and docosahexaenoic acid (DHA, C22:6n3) were determined by an optimized multiple reaction monitoring (MRM) method using ultra fast-liquid chromatography (UFLC) coupled with tandem mass spectrometry (MS/MS). Prostaglandin E2 (PGE2) was measured in serum samples by enzyme immunoassay. Results All measured PUFAs were significantly increased after treatment with insulin analogs plus metformin compared to before treatment levels. The mean AA/EPA ratio was significantly lower after treatment with insulin analogs plus metformin. A 22% decrease was observed in PGE2 levels after treatment with insulin analogs plus metformin compared to pretreatment levels (p?>?0.05). Conclusion The significant decrease in AA/EPA ratio indicates that insulin analog initiation therapy has anti-inflammatory properties by favoring the increase of n3 fatty acid EPA. PMID:24195588

  13. Simple model for the initial phase of a water plasma cloud about a large structure in space. Technical report

    Microsoft Academic Search

    D. E. Hastings; N. A. Gatsonis; T. Mogstad

    1987-01-01

    Large structures in the ionosphere will outgas or eject neutral water and perturb the ambient neutral environment. This water can undergo charge exchange with the ambient oxygen ions and form a water plasma cloud. Additionally, water dumps or thruster firings can create a water plasma cloud. A simple model for the evolution of a water plasma cloud about a large

  14. Characterization of extreme ultraviolet emission from laser-produced spherical tin plasma generated with multiple laser beams

    SciTech Connect

    Shimada, Y.; Nishimura, H.; Nakai, M.; Hashimoto, K.; Yamaura, M.; Tao, Y.; Shigemori, K.; Okuno, T.; Nishihara, K.; Kawamura, T.; Sunahara, A.; Nishikawa, T.; Sasaki, A.; Nagai, K.; Norimatsu, T.; Fujioka, S.; Uchida, S.; Miyanaga, N.; Izawa, Y.; Yamanaka, C. [Institute for Laser Technology, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan) and Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Institute for Laser Technology, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan) and Institute for Laser Technology, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan) and Department of Electrical and Electronic Engineering, Okayama University, Okayama 700-8530 (Japan); Kansai Research Establishment, Japan Atomic Energy Research Institute, 8-1, Umemidai, Kizu, Soraku, Kyoto 619-0215 (Japan); Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Institute for Laser Technology, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Institute for Laser Technology, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2005-01-31

    Spherical solid tin targets were illuminated uniformly with twelve beams from the Gekko XII laser system to create spherical plasmas, and the extreme ultraviolet (EUV) emission spectra from the plasmas were measured. The highest conversion efficiency of 3% to 13.5 nm EUV light in 2% bandwidth was attained for an irradiance of around 5x10{sup 10} W/cm{sup 2}. The experimental results were reproduced fairly well using a theoretical model taking the power balance in the plasma into consideration.

  15. Effect of pulsed laser target cleaning on ionisation and acceleration of ions in a plasma produced by a femtosecond laser pulse

    SciTech Connect

    Volkov, Roman V; Vorobiev, A A; Gordienko, Vyacheslav M; Dzhidzhoev, M S; Lachko, I M; Savel'ev, Andrei B; Uryupina, D S [Department of Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation); Mar'in, B V [D.V. Skobel'tsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2005-10-31

    The impurity layer on the surface of a solid target is shown to exert a significant effect on the characteristics of the ion current of the laser plasma produced under the action of ultrahigh-intensity femtosecond radiation on the surface of this target. The application of pulsed laser cleaning gives rise to an additional high-energy component in the ion spectrum of the target material. It is shown that the ion current parameters of the laser plasma such as the average and highest ion charge, the highest ion energy of the target material, etc., can be controlled by varying the lead time of the cleaning laser radiation. (interaction of laser radiation with matter. laser plasma)

  16. Comparison between Ni-Cr-40vol%TiC wear-resistant plasma sprayed coatings produced from self-propagating high-temperature synthesis and plasma densified powders

    Microsoft Academic Search

    C. Bartuli; R. W. Smith

    1996-01-01

    Plasma sprayed Ni-Cr-40vol%TiC coatings produced from powders obtained by self-propagating hightemperature synthesis (SHS)\\u000a and plasma densification (PD) processes are characterized. Chemical composition, microstructure, and mechanical properties,\\u000a such as microhardness and wear resistance, are evaluated and compared. SHS coatings exhibit good sliding wear performance.\\u000a \\u000a The exact stoichiometry of titanium carbide inclusions in the metallic matrix affects the dimension of the crystal

  17. A study of the quantity of some stable and labile coagulation factors in fresh-frozen plasma produced from whole blood stored for 24 hours in Iran

    PubMed Central

    Naghadeh, Hossin Timori; Roudkenar, Mehryar Habibi

    2009-01-01

    Background The aim of this study was to assess whether the quantities of some coagulation factors in fresh-frozen plasma (FFP) produced from whole blood stored at 4C for 24 h are adequate for their intended purpose. Materials and methods The amounts of some coagulation factors (fibrinogen, FV, FVII, FVIII, FX and FXI) in FFP separated from whole blood after storage at 4C for 24 h were compared with the amounts of the corresponding coagulation factors in FFP separated from whole blood within 8 h of donation. Results In 98% of the FFP units prepared after 24 h of storage, the levels of fibrinogen, FV, FVII, FX and FXI were greater than 0.5 IU/mL. The concentration of FVIII in the 24 h plasma units was 82% of that found in the FFP units prepared within 8 h of blood collection. In FFP, FVIII, FVII and FX were reduced by 38%, 8% and 3%, respectively, but FV, FXI and fibrinogen were not reduced. Conclusion These data suggest that there is good retention of coagulation factor activity in plasma produced from whole blood stored at 4C for 24 h and that such plasma would be an acceptable product for most patients requiring FFP. PMID:19290079

  18. Tunable bandgap energy of fluorinated nanocrystals for flash memory applications produced by low-damage plasma treatment.

    PubMed

    Huang, Chi-Hsien; Lin, Chih-Ting; Wang, Jer-Chyi; Chou, Chien; Ye, Yu-Ren; Cheng, Bing-Ming; Lai, Chao-Sung

    2012-11-30

    A plasma system with a complementary filter to shield samples from damage during tetrafluoromethane (CF(4)) plasma treatment was proposed in order to incorporate fluorine atoms into gadolinium oxide nanocrystals (Gd(2)O(3)-NCs) for flash memory applications. X-ray photoelectron spectroscopy confirmed that fluorine atoms were successfully introduced into the Gd(2)O(3)-NCs despite the use of a filter in the plasma-enhanced chemical vapour deposition system to shield against several potentially damaging species. The number of incorporated fluorine atoms can be controlled by varying the treatment time. The optimized memory window of the resulting flash memory devices was twice that of devices treated by a filterless system because more fluorine atoms were incorporated into the Gd(2)O(3)-NCs film with very little damage. This enlarged the bandgap energy from 5.48 to 6.83 eV, as observed by ultraviolet absorption measurements. This bandgap expansion can provide a large built-in electric field that allows more charges to be stored in the Gd(2)O(3)-NCs. The maximum improvement in the retention characteristic was >60%. Because plasma damage during treatment is minimal, maximum fluorination can be achieved. The concept of simply adding a filter to a plasma system to prevent plasma damage exhibits great promise for functionalization or modification of nanomaterials for advanced nanoelectronics while introducing minimal defects. PMID:23103683

  19. Tunable bandgap energy of fluorinated nanocrystals for flash memory applications produced by low-damage plasma treatment

    NASA Astrophysics Data System (ADS)

    Huang, Chi-Hsien; Lin, Chih-Ting; Wang, Jer-Chyi; Chou, Chien; Ye, Yu-Ren; Cheng, Bing-Ming; Lai, Chao-Sung

    2012-11-01

    A plasma system with a complementary filter to shield samples from damage during tetrafluoromethane (CF4) plasma treatment was proposed in order to incorporate fluorine atoms into gadolinium oxide nanocrystals (Gd2O3-NCs) for flash memory applications. X-ray photoelectron spectroscopy confirmed that fluorine atoms were successfully introduced into the Gd2O3-NCs despite the use of a filter in the plasma-enhanced chemical vapour deposition system to shield against several potentially damaging species. The number of incorporated fluorine atoms can be controlled by varying the treatment time. The optimized memory window of the resulting flash memory devices was twice that of devices treated by a filterless system because more fluorine atoms were incorporated into the Gd2O3-NCs film with very little damage. This enlarged the bandgap energy from 5.48 to 6.83 eV, as observed by ultraviolet absorption measurements. This bandgap expansion can provide a large built-in electric field that allows more charges to be stored in the Gd2O3-NCs. The maximum improvement in the retention characteristic was >60%. Because plasma damage during treatment is minimal, maximum fluorination can be achieved. The concept of simply adding a filter to a plasma system to prevent plasma damage exhibits great promise for functionalization or modification of nanomaterials for advanced nanoelectronics while introducing minimal defects.

  20. Diagnosis of Electron, Vibrational and Rotational Temperatures in an Ar/N2 Shock Plasma Jet Produced by a Low Pressure DC Cascade Arc Discharge

    NASA Astrophysics Data System (ADS)

    Li, Cong; Zhang, Jialiang; Yao, Zhi; Wu, Xingwei; Zhang, Chenfei; Ding, Hongbin

    2013-09-01

    In this paper, a low pressure Ar/N2 shock plasma jet with clearly multicycle alternating zones produced by a DC cascade arc discharge has been investigated by an emission spectral method combined with Abel inversion analysis. Plasma emission intensity, electron, vibrational and rotational temperatures of the shock plasma have been measured in the expansion and compression zones. The results indicate that the ranges of the measured electron temperature, vibrational temperature and rotational temperature are 1.1 eV to 1.6 eV, 0.2 eV to 0.7 eV and 0.19 eV to 0.22 eV, respectively, and it is found for the first time that the vibrational and rotational temperatures increase while the electron temperature decreases in the compression zones. The electron temperature departs from the vibrational and the rotational temperatures due to non-equilibrium plasma effects. Electrons and heavy particles could not completely exchange energy via collisions in the shock plasma jet under the low pressure of 620 Pa or so.

  1. Analysis of time- and space-resolved Na-, Ne-, and F-like emission from a laser-produced bromine plasma

    SciTech Connect

    Goldstein, W.H.; Young, B.K.F.; Osterheld, A.L.; Stewart, R.E.; Walling, R.S. (Lawrence Livermore National Lab., CA (USA)); Bar-Shalom, A. (Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev); Klapisch, M. (Lawrence Berkeley Lab., CA (USA))

    1991-01-16

    Advances in the efficiency and accuracy of computational atomic physics and collisional radiative modeling promise to place the analysis and diagnostic application of L-shell emission on a par with the simpler K-shell regime. Coincident improvements in spectroscopic plasma measurements yield optically thin emission spectra from small, homogeneous regions of plasma, localized both in space and time. Together, these developments can severely test models for high-density, high-temperature plasma formation and evolution, and non-LTE atomic kinetics. In this paper we present highly resolved measurements of n=3 to n=2 X-ray line emission from a laser-produced bromine micro-dot plasma. The emission is both space- and time-resolved, allowing us to apply simple, steady-state, 0-dimensional spectroscopic models to the analysis. These relativistic, multi-configurational, distorted wave collisional-radiative models were created using the HULLAC atomic physics package. Using these models, we have analyzed the F-like, Ne-like and Na-like (satellite) spectra with respect to temperature, density and charge-state distribution. This procedure leads to a full characterization of the plasma conditions. 9 refs., 3 figs.

  2. Electric field measurements from satellites-to-forbidden line ratios in an Omega-Upgrade laser-produced plasma. Semi-annual report, February 1May 31, 1996

    Microsoft Academic Search

    H. R. Griem; R. C. Elton; B. L. Welch

    1996-01-01

    Under this FY-96 NLUF program, the authors began their search for satellite lines to forbidden transitions for localized laser-induced electric field measurements by preparing in their laboratory a flat-field grazing incidence spectrograph for use on the OMEGA-Upgrade facility. This involved wavelength calibration using a (small) laser-produced plasma, as well as designing and constructing a mounting table compatible with the large

  3. Satellite spectra from laser-produced plasmas of Be, B, C, N, and O in He-like and Li-like configurations

    Microsoft Academic Search

    Piergiorgio Nicolosi; Giuseppe Tondello

    1977-01-01

    Satellite lines near the resonance lines in He-like and Li-like configurations have been observed in laser-produced plasmas of Be, B, C, N, and O. The observations have been made with a grazing incidence spectrograph with spatial resolution. These lines have been identified and compared with the existing theoretical predictions. Their intensities have been measured relative to the accompanying resonance lines.

  4. Measurement of O and OH radical produced by an atmospheric-pressure helium plasma jet nearby rat skin

    NASA Astrophysics Data System (ADS)

    Yonemori, Seiya; Ono, Ryo

    2013-09-01

    Atmospheric-pressure helium plasma jet is getting much attention because it enables many kinds of plasma applications including biomedical application such as sterilization and cancer treatment. In biomedical plasma applications, it is though that active species like ions and radicals play important role. Especially, OH radical and O atom is very chemically reactive that they are deemed as major factors in cancer treatment. In this study, O and OH density distribution and its temporal behavior nearby rat skin were measured to demonstrate actual application. Plasma discharge was under AC10 kVp-p, 10 kHz with 1.5 slm (standard litter per minute) of helium gas flow. OH density was around 1 ppm and O atom density was around 10 ppm at maximum. We also measured time-evolution of OH and O atom density. Both OH and O density was almost constant between discharge pulses because lifetime of active species could be prolonged in helium. And density distribution of both species varied depending on helium flow rate and water concentration on the surface; on rat skin or on the grass surface. Those results suggest the production mechanisms and provision mechanisms of O atom and OH radical by an atmospheric-pressure helium plasma jet. Atmospheric-pressure helium plasma jet is getting much attention because it enables many kinds of plasma applications including biomedical application such as sterilization and cancer treatment. In biomedical plasma applications, it is though that active species like ions and radicals play important role. Especially, OH radical and O atom is very chemically reactive that they are deemed as major factors in cancer treatment. In this study, O and OH density distribution and its temporal behavior nearby rat skin were measured to demonstrate actual application. Plasma discharge was under AC10 kVp-p, 10 kHz with 1.5 slm (standard litter per minute) of helium gas flow. OH density was around 1 ppm and O atom density was around 10 ppm at maximum. We also measured time-evolution of OH and O atom density. Both OH and O density was almost constant between discharge pulses because lifetime of active species could be prolonged in helium. And density distribution of both species varied depending on helium flow rate and water concentration on the surface; on rat skin or on the grass surface. Those results suggest the production mechanisms and provision mechanisms of O atom and OH radical by an atmospheric-pressure helium plasma jet. This work is partially supported by the Grant-in-Aid for Science Research by the Ministry of Education, Culture, Sport, Science and Technology.

  5. plasmas

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  6. Oxidation of vanadium with reactive oxygen plasma: A photoelectron spectroscopy study of the initial stages of the oxide growth process

    Microsoft Academic Search

    Andriy Romanyuk; Peter Oelhafen

    2007-01-01

    We report on the oxidation of vanadium surface in a low-temperature oxygen plasma studied by in-situ photoelectron spectroscopy (XPS, UPS). Pure vanadium foil was exposed to the oxygen plasma for different time intervals allowing to investigate early stages of the oxidemetal interface formation process and the oxide film growth. Upon increasing the exposure time to the oxygen plasma we identify

  7. Study of plasma start-up initiated by second harmonic electron cyclotron resonance heating on WEGA experiment

    NASA Astrophysics Data System (ADS)

    Preynas, M.; Laqua, H. P.; Otte, M.; Stange, T.; Wauters, T.; Amus, D.

    2014-02-01

    Although both 1st harmonic ordinary mode (O1) and 2nd harmonic extra-ordinary mode (X2) have been successfully used to initiate pre-ionization and breakdown in many devices, a complete theoretical model is still missing to explain the success of this method. Moreover, some experimental observations are not completely understood, such as what occurs during the delay time between the turn-on of ECRH power and first signals of density or light measurements. Since during this free period the ECRH power has to be absorbed by in-vessel components, it is of prime importance to know what governs this delay time. Recently, dedicated start-up experiments have been performed on WEGA, using a 28 GHz ECRH system in X2-mode. This machine has the interesting capability to be run also as a tokamak allowing comparative experiments between stellarator (?/2? > 0) and tokamak (?/2? = 0) configurations. Different scans in heating power, neutral gas pressure, and rotational transform (?) show clearly that the start-up is a two step process. A first step following the turn-on of the ECRH power during which no measurable electron density (or just above the noise level in some cases), ECE and radiated power is detected. Its duration depends strongly on the level of injected power. The second step corresponds to the gas ionization and plasma expansion phase, with a velocity of density build-up and filling-up of the vessel volume depending mainly on pressure, gas and rotational transform. Moreover, an interesting scenario of ECRH pre-ionization without loop voltage in tokamak configuration by applying a small optimal vertical field is relevant for start-up assistance on future experiments like ITER. The results from this experimental parametric study are useful for the modeling of the start-up assisted by the second harmonic electron cyclotron resonance heating. The aim of this work is to establish predictive scenarios for both ITER and W7-X operation.

  8. Study of plasma start-up initiated by second harmonic electron cyclotron resonance heating on WEGA experiment

    SciTech Connect

    Preynas, M.; Laqua, H. P.; Otte, M.; Stange, T.; Amus, D. [Max Planck Institut fr Plasmaphysik, EURATOM Association, D-17491 Greifswald (Germany); Wauters, T. [Association Euratom-Belgian State, LPP-ERM/KMS, 1000 Brussels (Belgium)

    2014-02-12

    Although both 1st harmonic ordinary mode (O1) and 2nd harmonic extra-ordinary mode (X2) have been successfully used to initiate pre-ionization and breakdown in many devices, a complete theoretical model is still missing to explain the success of this method. Moreover, some experimental observations are not completely understood, such as what occurs during the delay time between the turn-on of ECRH power and first signals of density or light measurements. Since during this free period the ECRH power has to be absorbed by in-vessel components, it is of prime importance to know what governs this delay time. Recently, dedicated start-up experiments have been performed on WEGA, using a 28 GHz ECRH system in X2-mode. This machine has the interesting capability to be run also as a tokamak allowing comparative experiments between stellarator (?/2? > 0) and tokamak (?/2? = 0) configurations. Different scans in heating power, neutral gas pressure, and rotational transform (?) show clearly that the start-up is a two step process. A first step following the turn-on of the ECRH power during which no measurable electron density (or just above the noise level in some cases), ECE and radiated power is detected. Its duration depends strongly on the level of injected power. The second step corresponds to the gas ionization and plasma expansion phase, with a velocity of density build-up and filling-up of the vessel volume depending mainly on pressure, gas and rotational transform. Moreover, an interesting scenario of ECRH pre-ionization without loop voltage in tokamak configuration by applying a small optimal vertical field is relevant for start-up assistance on future experiments like ITER. The results from this experimental parametric study are useful for the modeling of the start-up assisted by the second harmonic electron cyclotron resonance heating. The aim of this work is to establish predictive scenarios for both ITER and W7-X operation.

  9. Quasi-phase-matching induced enhancement of the groups of high-order harmonics generating in various multi-jet plasmas produced using perforated targets and modulated heating pulses

    NASA Astrophysics Data System (ADS)

    Ganeev, R. A.; Suzuki, M.; Yoneya, S.; Kuroda, H.

    2014-11-01

    Quasi-phase-matching (QPM) of the harmonics of ultrashort pulses in the perforated aluminum, indium, and chromium plasma plumes produced by different techniques is analyzed. We extend our recent studies (2014 J. Phys. B: At. Mol. Opt. Phys. 47 105401) to other plasma ablations and show the advantages of modulated plasma profiles for the harmonic generation. We demonstrate the 20 growth of QPM-enhanced harmonics in the plasma produced on the perforated aluminum surface. The calculations of plasma concentrations at different delays and distances from ablating targets are presented. We show the tuning of maximally enhanced harmonics using variable excitation of metallic targets at the conditions of QPM, as well as demonstrate the use of a two-color pump of the four-jet indium plasma for enhancement of the harmonics, which were not present in the spectra obtained from the extended indium plasma.

  10. EBT2 dosimetry of x-rays produced by the electron beam from a Plasma Focus for medical applications

    SciTech Connect

    Ceccolini, E.; Mostacci, D.; Sumini, M. [Montecuccolino Nuclear Engineering Laboratory - DIENCA, University of Bologna, via dei Colli 16, I-40136 Bologna (Italy); Rocchi, F. [Montecuccolino Nuclear Engineering Laboratory - DIENCA, University of Bologna, via dei Colli 16, I-40136 Bologna (Italy); UTFISSM-PRONOC, ENEA, via Martiri di Monte Sole 4, I-40129 Bologna (Italy); Tartari, A. [Department of Physics, Ferrara University, via Saragat 1, I-44122 Ferrara (Italy); Mariotti, F. [ENEA, IRP-DOS, via dei Colli 16, I-40136 Bologna (Italy)

    2012-09-01

    The electron beam emitted from the back of Plasma Focus devices is being studied as a radiation source for intraoperative radiation therapy applications. A Plasma Focus device is being developed to this aim, to be utilized as an x-ray source. The electron beam is driven to impinge on 50 {mu}m brass foil, where conversion x-rays are generated. Measurements with gafchromic film are performed to analyse the attenuation of the x-rays beam and to predict the dose given to the culture cell in radiobiological experiments to follow.

  11. Measurement of the Radiofrequency-microwave Pulse Produced in Experiments of Laser-plasma Interaction in the ABC Laser Facility

    NASA Astrophysics Data System (ADS)

    Consoli, Fabrizio; De Angelis, Riccardo; Andreoli, Pierluigi; Cristofari, Giuseppe; Di Giorgioa, Giorgio

    The emission of electromagnetic waves in the radiofrequency-microwave range has been observed in many experiments of laser- plasma interaction. These fields can have very high intensity and estimated frequency band up to several gigahertz. The radiation normally affects the behaviour of most of the detectors, often up to hundreds of nanoseconds from the laser pulse, and can represent a serious limitation for the time-of-flight detection of fast particles, and in general for the safe operation of the electronic equipment. In this work we describe the measurements of this electromagnetic pulse, under different conditions of laser-plasma interaction.

  12. Viral particles drive rapid differentiation of memory B cells into secondary plasma cells producing increased levels of antibodies.

    PubMed

    Zabel, Franziska; Mohanan, Deepa; Bessa, Juliana; Link, Alexander; Fettelschoss, Antonia; Saudan, Philippe; Kndig, Thomas M; Bachmann, Martin F

    2014-06-15

    Extensive studies have been undertaken to describe naive B cells differentiating into memory B cells at a cellular and molecular level. However, relatively little is known about the fate of memory B cells upon Ag re-encounter. We have previously established a system based on virus-like particles (VLPs), which allows tracking of VLP-specific B cells by flow cytometry as well as histology. Using allotype markers, it is possible to adoptively transfer memory B cells into a naive mouse and track responses of naive and memory B cells in the same mouse under physiological conditions. We have observed that VLP-specific memory B cells quickly differentiated into plasma cells that drove the early onset of a strong humoral IgG response. However, neither IgM(+) nor IgG(+) memory B cells proliferated extensively or entered germinal centers. Remarkably, plasma cells derived from memory B cells preferentially homed to the bone marrow earlier and secreted increased levels of Abs when compared with primary plasma cells derived from naive B cells. Hence, memory B cells have the unique phenotype to differentiate into highly effective secondary plasma cells. PMID:24821969

  13. Analysis, simulation, and experimental studies of YAG and CO2 laser-produced plasma for EUV lithography sources

    E-print Network

    Harilal, S. S.

    lithography sources A. Hassanein, V. Sizyuk, S.S. Harilal, and T. Sizyuk School of Nuclear Engineering emission, source formation, debris generation, and conversion efficiency. The much higher reflectivity thinner plumes with higher velocity and in a better formation of plasma properties (temperature

  14. Studies of resonantly produced plasmas in the H-1NF heliac using a far-infrared scanning interferometer

    E-print Network

    Howard, John

    using ion cyclotron resonant heating at 0.5 T. II. INTERFEROMETER SYSTEM Figure 1 shows a Gaussian ray trace of the multiview system4 with three plasma views installed. The support struc- ture with an electric motor to provide a stable computer controlled rotational speed and to make the system acoustically

  15. Femtosecond-laser-produced low-density plasmas in transparent biological media: a tool for the creation of chemical, thermal, and thermomechanical effects below the optical breakdown threshold

    NASA Astrophysics Data System (ADS)

    Vogel, Alfred; Noack, Joachim; Huettmann, Gereon; Paltauf, Guenther

    2002-04-01

    The irradiance threshold for femtosecond optical breakdown in aqueous media is approximately equals 1.0x1013W cm-2. At the breakdown threshold, a plasma with a free electron density of about 1021cm-3 is generated, and the energy density in the breakdown region is sufficiently high to cause the formation of a bubble which can be experimentally observed. We found previously that plasmas with a free electron density <1021cm-3 are formed also in a fairly large irradiance range below the breakdown threshold. The present study investigates the chemical, thermal, and thermomechanical effects produced by these low-density plasmas. We use a rate equation model considering multiphoton ionization and produced by these low-density plasmas. We use a rate equation model considering multiphoton ionization and avalanche ionization to numerically simulate the temporal evolution of the free electron density during the laser pulse for a given irradiance, and to calculate the irradiance dependence of the free-electron density and volumetric energy density reached at the end of the laser pulse. The value of the energy density created by each laser pulse is then used to calculate the temperature distribution in the focal region after application of a single laser pulse and of series of pulses. The results of the temperature calculations yield, finally, the starting point for calculations of the thermoelastic stresses that are generated during the formation of the low-density plasmas. We found that, particularly for short wavelengths, a large 'tuning range' exists for the creation of spatially extremely confined chemical, thermal and mechanical effects via free electron generation through nonlinear absorption. Photochemical effects dominate at the lower end of this irradiance range, whereas at the upper end they are mixed with thermal effects and modified by thermoelastic stresses. Above the breakdown threshold, the spatial confinement is partly destroyed by cavitation bubble formation, and the laser-induced effects become more disruptive. Our simulations revealed that the highly localized ablation of intracellular structures and intranuclear chromosome dissection recently demonstrated by other researchers are probably mediated by free-electron- induced chemical bond breaking and not related to heating or thermoelastic stresses. We conclude that low density plasmas below the optical breakdown threshold can be a versatile tool for the manipulation of transparent biological media and other transparent materials. (enabling, e.g., the generation of optical waveguides in bulk glass). Low density plasmas may, however, also be a potential hazard in multiphoton microscopy and higher harmonic imaging.

  16. Principal component analysis of electron beams generated in K-shell aluminum X-pinch plasma produced by a compact LC-generator

    NASA Astrophysics Data System (ADS)

    Yilmaz, M. F.; Danisman, Y.; Larour, J.; Aranchuk, L.

    2015-06-01

    Principal component analysis (PCA) method is applied and compared with the line ratios of H-like and He-like transitions, in order to investigate the effects of electron beam on the K-shell Aluminum synthetic spectra. It is also used as a diagnostics to estimate the plasma parameters of K-shell Al X-pinch plasma spectrum. This spectrum is produced by the explosion of two 25-?m Al wires on a compact LC (40 kV, 200 kA) generator. The database for the principal component extraction is created over a previously developed, non-LTE, collisional radiative K-shell Aluminum model. As a result, PCA shows an agreement with the line ratios which are sensitive to plasma electron temperatures, densities and beam fractions. Principal component analysis also illustrates that the addition to the non-LTE model of a fraction f of electrons in an energetic beam, generates the clusters in a three dimensional vector space which are translations of each other and follows reverse v-shaped cascade trajectories, except for the f = 0.0 case. Modeling of a typical shot by PCA gives the plasma electron temperature of Te = 100 eV, density of Ne = 1 1020 cm-3 and hot electron fraction of f = 0.2 (with a beam energy centered at 10 keV).

  17. Autoresonant excitation of antiproton plasmas.

    PubMed

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

    2011-01-14

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

  18. Diblock copolymer of bacterial cellulose and poly(methyl methacrylate) initiated by chain-end-type radicals produced by mechanical scission of glycosidic linkages of bacterial cellulose.

    PubMed

    Sakaguchi, Masato; Ohura, Takeshi; Iwata, Tadahisa; Takahashi, Shuhei; Akai, Shuji; Kan, Toshiyuki; Murai, Hisao; Fujiwara, Motoyasu; Watanabe, Osamu; Narita, Mamiko

    2010-11-01

    Bacterial cellulose (BC) was mechanically fractured in vacuum at 77 K; this resulted in the scission of the ?-1,4 glycosidic linkages of BC. The chain-end-type radicals (mechanoradicals) generated from the scissions were assigned by electron spin resonance (ESR) spectral analyses. A diblock copolymer of BC and poly(methyl methacrylate) (BC-block-PMMA) was produced by the mechanical fracture of BC with MMA (methyl methacrylate) in vacuum at 77 K. Radical polymerization of MMA was initiated by the mechanoradicals located on the BC surface. The BC surface was fully covered with the PMMA chains of the BC-block-PMMA. Novel modification of the BC surface with the BC-block-PMMA was confirmed by spectral analyses of ESR, Fourier-transform infrared, (1)H NMR, and gel permeation chromatography. PMID:20882979

  19. Spectral characteristics of quantum-cascade laser operating at 10.6 ?m wavelength for a seed application in laser-produced-plasma extreme UV source.

    PubMed

    Nowak, Krzysztof M; Ohta, Takeshi; Suganuma, Takashi; Yokotsuka, Toshio; Fujimoto, Junichi; Mizoguchi, Hakaru; Endo, Akira

    2012-11-15

    In this Letter, we investigate, for the first time to our knowledge, the spectral properties of a quantum-cascade laser (QCL) from a point of view of a new application as a laser seeder for a nanosecond-pulse high-repetition frequency CO(2) laser operating at 10.6 ?m wavelength. The motivation for this work is a renewed interest in such a pulse format and wavelength driven by a development of extreme UV (EUV) laser-produced-plasma (LPP) sources. These sources use pulsed multikilowatt CO(2) lasers to drive the EUV-emitting plasmas. Basic spectral performance characteristics of a custom-made QCL chip are measured, such as tuning range and chirp rate. The QCL is shown to have all essential qualities of a robust seed source for a high-repetition nanosecond-pulsed CO(2) laser required by EUV LPP sources. PMID:23164906

  20. Mutation breeding of lycopene-producing strain Blakeslea trispora by a novel atmospheric and room temperature plasma (ARTP).

    PubMed

    Qiang, Wang; Ling-ran, Feng; Luo, Wei; Han-guang, Li; Lin, Wang; Ya, Zhou; Xiao-bin, Yu

    2014-09-01

    To improve the fermentation efficiency of lycopene, a plasma jet, driven by an active helium atom supplied with atmospheric and room temperature plasma (ARTP) biological breeding system, was used as a new method to generate mutations in Blakeslea trispora (-). After several rounds of screening, a mutant A5 with high concentration of lycopene and dry biomass was isolated, which showed a maximum lycopene concentration (26.4 0.2 mg/g dry biomass) which was 55 % higher than the parent strain (16.9 0.3 mg/g dry biomass) in the production of lycopene. Compared with parent strain, B. trispora A5 required less dissolved oxygen (10 % less than that of parent strain) to reach maximum concentration in a 5-L stirred tank reactor batch fermentation. PMID:24903962