WorldWideScience

Sample records for plasma initiation produced

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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. (authors)

  2. Initial development of ponderomotive filaments in plasma from intense hot spots produced by a random phase plate

    International Nuclear Information System (INIS)

    Rose, H.A.; DuBois, D.F.

    1993-01-01

    Local intensity peaks, hot spots, in laser beams may initiate self-focusing, in lieu of linear instabilities. If the hot spot power, P, contains several times the critical power, P c , and if the plasma density, n, is small compared to the critical density, n c , then on a time scale less than an acoustic transit time across the hot spot radius, τ ia , the hot spot collapses, capturing order unity of the initial hot spot power. The collapse time is determined as a universal function of P/P c and τ ia . The focal region moves towards the laser with an initially supersonic speed, and decelerates as it propagates. The power of this back propagating focus decreases monotonically until the critical power is reached. This limiting, shallowest, focus develops on a time scale long compared to τ ia and corresponds to the focus obtained in a model with adiabatically responding ions. For low-density plasma nonlinear ion effects terminate collapse and a bound on the transient intensity amplification is obtained as a universal function of the optics f/number, F, and n/n c . The boundary between thermal and ponderomotive regimes depends upon F and not the laser intensity

  3. Properties of the Dense Plasma Produced in Plasma Focus

    International Nuclear Information System (INIS)

    Peacock, N.J.; Wilcock, P.D.; Speer, R.J.; Morgan, P.D.

    1969-01-01

    The plasma produced by the focus or quasi-cylindrical magnetic compression which occurs at the open end of a metal-walled, coaxial plasma gun has been studied, using the electrical waveforms and the electromagnetic and reaction particle, emission. The electromagnetic radiation in the XUV region of the spectrum has previously been briefly reported, and the present paper describes further more detailed analyses of the line emission at wavelengths shorter than 10 Å when impurities are added to the gas filling. The emission is characteristic of a plasma with a temperature of a few keV and a density greater than 10 19 cm -3 , while the appearance of optical transitions in highly stripped ions, e. g. A XVIII, gives a measure of the thermalization in the plasma. The stored electrical energy has been doubled and the scaling of the neutron emission with the applied voltage and the initial particle density is presented. The duration of the neutron and X-ray emission is considerably longer than the observed instability growth time in the plasma filament. Calculations of the mode of heating and the confinement of the plasma are compared with experimental observations. (author)

  4. Diagnostics of laser-produced plasmas

    Directory of Open Access Journals (Sweden)

    Batani Dimitri

    2016-12-01

    Full Text Available We present the general challenges of plasma diagnostics for laser-produced plasmas and give a few more detailed examples: spherically bent crystals for X-ray imaging, velocity interferometers (VISAR for shock studies, and proton radiography.

  5. Spark gap produced plasma diagnostics

    International Nuclear Information System (INIS)

    Chang, H.Y.

    1990-01-01

    A Spark Gap (Applied voltage : 2-8KV, Capacitor : 4 Micro F. Dia of the tube : 1 inch, Electrode distance : .3 ∼.5 inch) was made to generate a small size dynamic plasma. To measure the plasma density and temperature as a function of time and position, we installed and have been installing four detection systems - Mach-Zehnder type Interferometer for the plasma refractivity, Expansion speed detector using two He-Ne laser beams, Image Processing using Lens and A Optical-Fiber Array for Pointwise Radiation Sensing, Faraday Rotation of a Optical Fiber to measure the azimuthal component of B-field generated by the plasma drift. These systems was used for the wire explosion diagnostics, and can be used for the Laser driven plasma also

  6. Electron acceleration using laser produced plasmas

    CERN Multimedia

    CERN. Geneva; Landua, Rolf

    2005-01-01

    Low density plasmas have long been of interest as a potential medium for particle acceleration since relativistic plasma waves are capable of supporting electric fields greater than 100 GeV/m. The physics of particle acceleration using plasmas will be reviewed, and new results will be discussed which have demonstrated that relatively narrow energy spread (<3%) beams having energies greater than 100 MeV can be produced from femtosecond laser plasma interactions. Future experiments and potential applications will also be discussed.

  7. High beta plasma operation in a toroidal plasma producing device

    International Nuclear Information System (INIS)

    Clarke, J.F.

    1978-01-01

    A high beta plasma is produced in a plasma producing device of toroidal configuration by ohmic heating and auxiliary heating. The plasma pressure is continuously monitored and used in a control system to program the current in the poloidal field windings. Throughout the heating process, magnetic flux is conserved inside the plasma and the distortion of the flux surfaces drives a current in the plasma. As a consequence, the total current increases and the poloidal field windings are driven with an equal and opposing increasing current. The spatial distribution of the current in the poloidal field windings is determined by the plasma pressure. Plasma equilibrium is maintained thereby, and high temperature, high beta operation results

  8. Field reversal produced by a plasma gun

    International Nuclear Information System (INIS)

    Hartman, C.W.; Condit, W.; Granneman, E.H.A.; Prono, D.; Smith, A.C. Jr.; Taska, J.; Turner, W.C.

    1980-01-01

    Experimental results are presented of the production of Field-Reversed Plasma with a high energy coaxial plasma gun. The gun is magnetized with solenoids inside the center electrode and outside the outer electrode so that plasma emerging from the gun entrains the radial fringer field at the muzzle. The plasma flow extends field lines propagating a high electrical conductivity, the flux inside the center electrode should be preserved. However, for low flux, the trapped flux exceeds by 2 or more the initial flux, possibly because of helical deformation of the current channel extending from the center electrode

  9. Energy transport in laser produced plasmas

    International Nuclear Information System (INIS)

    Key, M.H.

    1989-06-01

    The study of energy transport in laser produced plasmas is of great interest both because it tests and develops understanding of several aspects of basic plasma physics and also because it is of central importance in major applications of laser produced plasmas including laser fusion, the production of intense X-ray sources, and X-ray lasers. The three sections cover thermal electrons (energy transport in one dimension, plane targets and lateral transport from a focal spot, thermal smoothing, thermal instabilities), hot electrons (preheating in one dimension, lateral transport from a focal spot) and radiation (preheating in one dimension, lateral transport and smoothing, instabilities). (author)

  10. Initial plasma production by induction electric field on QUEST tokamak

    International Nuclear Information System (INIS)

    Hasegawa, Makoto; Nakamura, Kazuo; Sato, Kohnosuke

    2007-01-01

    Induction electric field by center solenoid coil plays a roll to produce initial plasma. According to Townsend avalanche theory, minimum electric field for plasma breakdown depends on neutral gas pressure and connection length. On QUEST spherical tokamak, a connection length is evaluated as 966m on null point neighborhood with coil current ratio I PF26 /I CS =0.1, and induction electric field considering eddy current of vacuum vessel is evaluated as about 0.1 V/m on null point neighborhood. With Townsend avalanche theory, these values manage to produce initial plasma on QUEST. (author)

  11. Adventures in Laser Produced Plasma Research

    Energy Technology Data Exchange (ETDEWEB)

    Key, M

    2006-01-13

    In the UK the study of laser produced plasmas and their applications began in the universities and evolved to a current system where the research is mainly carried out at the Rutherford Appleton Laboratory Central Laser Facility ( CLF) which is provided to support the universities. My own research work has been closely tied to this evolution and in this review I describe the history with particular reference to my participation in it.

  12. Spectroscopic and corpuscular analysis of laser-produced carbon plasma

    International Nuclear Information System (INIS)

    Czarnecka, A.; Kubkowska, M.; Kowalska-Strzeciwilk, E.; Parys, P.; Sadowski, M.J.; Skladnik-Sadowska, E.; Malinowski, K.; Kwiatkowski, R.; Ladygina, M.

    2013-01-01

    The paper describes spectroscopic and corpuscular measurements of laser-produced carbon plasma, which was created at surfaces of three targets made of CFC of the Snecma-N11 type with different crystallographic orientations. In order to irradiate the investigated samples the use was made of a Nd:YAG laser. Experiments were performed in a vacuum chamber under the initial pressure equal to 5.10-5 mbar. A Mechelle 900 optical spectrometer equipped with a CCD detector was used to record spectra emitted from the produced carbon-plasma. The recorded optical spectra showed distinct carbon lines ranging from CI to CIV. Basing on the Stark broadening of the CII 426.7 nm line it was possible to estimate the electron density of plasma from each investigated sample. Corpuscular measurements of the emitted ions were carried out by means of an electrostatic ion-energy analyzer and ion collector.

  13. Plasma treatment for producing electron emitters

    Science.gov (United States)

    Coates, Don Mayo; Walter, Kevin Carl

    2001-01-01

    Plasma treatment for producing carbonaceous field emission electron emitters is disclosed. A plasma of ions is generated in a closed chamber and used to surround the exposed surface of a carbonaceous material. A voltage is applied to an electrode that is in contact with the carbonaceous material. This voltage has a negative potential relative to a second electrode in the chamber and serves to accelerate the ions toward the carbonaceous material and provide an ion energy sufficient to etch the exposed surface of the carbonaceous material but not sufficient to result in the implantation of the ions within the carbonaceous material. Preferably, the ions used are those of an inert gas or an inert gas with a small amount of added nitrogen.

  14. Thermonuclear fusion plasma produced by lasers

    International Nuclear Information System (INIS)

    Yamanaka, C.; Yokoyama, M.; Nakai, S.; Sasaki, T.; Yoshida, K.; Matoba, M.; Yamabe, C.; Tschudi, T.; Yamanaka, T.; Mizui, J.; Yamaguchi, N.; Nishikawa, K.

    1975-01-01

    Recently, much attention has been focused on laser fusion schemes using high-density plasmas produced by implosion. Scientific-feasibility laser-fusion experiments are now in time. But the physics of interaction between laser and plasma, the high-compression technique and the development of high-power lasers are still important problems to be solved if laser fusion is to make some progress. In the field of laser-plasma coupling, experiments were carried out in which hydrogen and deuterium sticks were bombarded by laser beams; in these experiments, a glass-laser system, LETKKO-I, with an energy of 50 J in a nanosecond pulse, and a double-discharge TEA CO 2 laser system with an energy of 100 J in a 100-ns pulse were used. A decrease in reflectivity occurred at a laser intensity one order of magnitude higher than the parametric-instability threshold. Self-phase modulation of scattered light due to modulational instability was found. A Brillouin-backscattering isotope effect due to the hydrogen and deuterium plasma has also been observed in the red-side part of the SHG-light. Preliminary compression experiments have been carried out using a glass-laser system LETKKO-II, with an energy of 250-1000 J in a ns-pulse. A hologram has been used to study shock waves in the plasma due to the SHG-light converted from the main laser beam. Development of high-power lasers has been promoted, such as disc-glass lasers, E-beam CO 2 lasers and excimer lasers. (author)

  15. Initial operation of NSTX with plasma control

    International Nuclear Information System (INIS)

    Gates, D.; Bell, M.; Ferron, J.; Kaye, S.; Menard, J.; Mueller, D.; Neumeyer, C.; Sabbagh, S.

    2000-01-01

    First plasma, with a maximum current of 300kA, was achieved on NSTX in February 1999. These results were obtained using preprogrammed coil currents. The first controlled plasmas on NSTX were made starting in August 1999 with the full 1MA plasma current achieved in December 1999. The controlled quantities were plasma position (R, Z) and current (Ip). Variations in the plasma shape are achieved by adding preprogrammed currents to those determined by the control parameters. The control system is fully digital, with plasma position and current control, data acquisition, and power supply control all occurring in the same four-processor real time computer. The system uses the PCS (Plasma Control Software) system designed at General Atomics. Modular control algorithms, specific to NSTX, were written and incorporated into the PCS. The application algorithms do the actual control calculations, with the PCS handling data passing. The control system, including planned upgrades, will be described, along with results of the initial controlled plasma operations. Analysis of the performance of the control system will also be presented

  16. Molybdenum disilicide composites produced by plasma spraying

    International Nuclear Information System (INIS)

    Castro, R.G.; Hollis, K.J.; Kung, H.H.; Bartlett, A.H.

    1998-01-01

    The intermetallic compound, molybdenum disilicide (MoSi 2 ) is being considered for high temperature structural applications because of its high melting point and superior oxidation resistance at elevated temperatures. The lack of high temperature strength, creep resistance and low temperature ductility has hindered its progress for structural applications. Plasma spraying of coatings and structural components of MoSi 2 -based composites offers an exciting processing alternative to conventional powder processing methods due to superior flexibility and the ability to tailor properties. Laminate, discontinuous and in situ reinforced composites have been produced with secondary reinforcements of Ta, Al 2 O 3 , SiC, Si 3 N 4 and Mo 5 Si 3 . Laminate composites, in particular, have been shown to improve the damage tolerance of MoSi 2 during high temperature melting operations. A review of research which as been performed at Los Alamos National Laboratory on plasma spraying of MoSi 2 -based composites to improve low temperature fracture toughness, thermal shock resistance, high temperature strength and creep resistance will be discussed

  17. Study on Laser Induced Plasma Produced in Liquid

    International Nuclear Information System (INIS)

    Tsuda, N.; Yamada, J.

    2003-01-01

    When an intense laser light is focused in liquid, a hot plasma is produced at the focal spot. The breakdown threshold and the transmittance of sodium choroids solution are observed using excimer laser or YAG laser. The breakdown threshold decreases with increasing NaCl concentration. Threshold intensity of plasma produced by YAG laser is lower than excimer laser. The behavior of plasma development is observed by a streak camera. The plasma produced by a YAG laser develops only backward. However, the plasma produced by excimer laser develops not only backward but also forward same as the plasma development in high-pressure gases

  18. Measurement of Debye length in laser-produced plasma.

    Science.gov (United States)

    Ehler, W.

    1973-01-01

    The Debye length of an expanded plasma created by placing an evacuated chamber with an entrance slit in the path of a freely expanding laser produced plasma was measured, using the slab geometry. An independent measurement of electron density together with the observed value for the Debye length also provided a means for evaluating the plasma electron temperature. This temperature has applications in ascertaining plasma conductivity and magnetic field necessary for confinement of the laser produced plasma. Also, the temperature obtained would be useful in analyzing electron-ion recombination rates in the expanded plasma and the dynamics of the cooling process of the plasma expansion.

  19. Studies on the propagation of relativistic plasma waves in high density plasmas produced by hypersonic ionizing shock waves

    International Nuclear Information System (INIS)

    Williams, R.L.; Johnson, J.A. III

    1993-01-01

    The feasibility of using an ionizing shock wave to produce high density plasmas suitable for the propagation large amplitude relativistic plasma waves is being investigated. A 20 kv arc driven shock tube of coaxial geometry produces a hypersonic shock wave (10 p > 10 17 cm -3 ). The shock can be made to reflect off the end of the tube, collide with its wake, and thus increase the plasma density further. After reflecting, the plasma is at rest. The shock speed is measured using piezoelectric pressure probes and the ion density is measured using laser induced fluorescence (LIF) techniques on argon 488.0 nm and 422.8 nm lines. The future plans are to excite large amplitude relativistic plasma waves in this plasma by either injecting a short pulse laser (Laser Wake Field Scheme), two beating lasers (Plasma Beat Wave Scheme), or a short bunch of relativistic electrons (Plasma Wake Field Scheme). Results of recent computational and theoretical studies, as well as initial experimental measurements on the plasma using LIF, are reported. Implications for the application of high density plasmas produced in this way to such novel schemes as the plasma wave accelerator, photon accelerator, plasma wave undulator, and also plasma lens, are discussed. The effect of plasma turbulence is also discussed

  20. Laser plasma focus produced in a ring target

    International Nuclear Information System (INIS)

    Saint-Hilaire, G.; Szili, Z.

    1976-01-01

    A new geometry for generating a laser-produced plasma is presented. A toroidal mirror is used to focus a CO 2 laser beam on the inside wall of a copper ring target. The plasma produced converges at the center of the ring where an axial plasma focus is formed. High-speed photography shows details of a plasma generated at a distance from the target surface. This new geometry could have important applications in the field of x-ray lasers

  1. Interaction between laser-produced plasma and guiding magnetic field

    International Nuclear Information System (INIS)

    Hasegawa, Jun; Takahashi, Kazumasa; Ikeda, Shunsuke; Nakajima, Mitsuo; Horioka, Kazuhiko

    2013-01-01

    Transportation properties of laser-produced plasma through a guiding magnetic field were examined. A drifting dense plasma produced by a KrF laser was injected into an axisymmetric magnetic field induced by permanent ring magnets. The plasma ion flux in the guiding magnetic field was measured by a Faraday cup at various distances from the laser target. Numerical analyses based on a collective focusing model were performed to simulate plasma particle trajectories and then compared with the experimental results. (author)

  2. Laser produced plasma density measurement by Mach-Zehnder interferometry

    International Nuclear Information System (INIS)

    Vaziri, A.; Kohanzadeh, Y.; Mosavi, R.K.

    1976-06-01

    This report describes an optical interferometric method of measuring the refractive index of the laser-produced plasma, giving estimates of its electron density. The plasma is produced by the interaction of a high power pulsed CO 2 laser beam with a solid target in the vacuum. The time varying plasma has a transient electron density. This transient electron density gives rise to a changing plasma refractive index. A Mach-Zehnder ruby laser interferometer is used to measure this refractive index change

  3. Microwave produced plasma in a Toroidal Device

    Science.gov (United States)

    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.

  4. Oxide cathodes produced by plasma deposition

    International Nuclear Information System (INIS)

    Scheitrum, G.; Caryotakis, G.; Pi, T.; Umstattd, R.; Brown, I.; Montiero, O.

    1997-01-01

    These are two distinct applications for high-current-density, long-life thermionic cathodes. The first application is as a substitute for explosive emission cathodes used in high-power microwave (HPM) devices being developed for Air Force programs. The second application is in SLAC's X-band klystrons for the Next Linear Collider (NLC). SLAC, UCD, and LBL are developing a plasma deposition process that eliminates the problems with binders, carbonate reduction, peeling, and porosity. The emission layer is deposited using plasma deposition of metallic barium in vacuum with an oxygen background gas. An applied bias voltage drives the oxide plasma into the nickel surface. Since the oxide is deposited directly, it does not have problems with poisoning from a hydrocarbon binder. The density of the oxide layer is increased from the 40--50% for standard oxide cathodes to nearly 100% for plasma deposition

  5. Initial value problem for plasma oscillations

    International Nuclear Information System (INIS)

    Li, J.; Spies, G.O.

    1991-01-01

    The solution of the initial value problem for the linearized one-dimensional electron Vlasov--Poisson equations in a field-free homogeneous equilibrium is examined for small and for large ratios κ of Debye length and wavelength, assuming initial perturbing distribution functions varying on the same velocity scale as the equilibrium. Previously known approximations of the initial evolution (which, unlike the time-asymptotic one, does not depend on analyticity assumptions) are extended to longer times, and to arbitrary stable or unstable equilibria: In the quasifluid regime (small κ), the electric field, within an additive error O(κ 2 ), and independently of the initial data, performs an oscillation near the plasma frequency that corresponds to an eigenmode if it is unstable or marginal, but to an approximate eigenmode arising from the continuous spectrum otherwise. If other unstable or marginal modes are present, these influence only the time-asymptotic behavior because their amplitudes are O(κ 2 ) initially. In the ballistic regime (large κ), there are no instabilities and the perturbing density, now within an error O(κ -2 ), is the Fourier transform of the initial perturbing distribution function, thus following an arbitrary decay law that is independent of the equilibrium. The errors are shown to be time-independent, implying that either approximation is relevant at least until the perturbing density has essentially damped out. Hence the dominating damping mechanism (in the stable case) is Landau damping if κ much-lt 1, but ballistic particle mixing if κ much-gt 1

  6. Plasmas produced by incident laser in solids

    International Nuclear Information System (INIS)

    Oliveira Campos, D. de; Boeckelmann, H.K.

    1984-01-01

    The experimental arrangement for plasma production by incident laser in solids and a system of diagnostics are presented. The system of diagnostics allows: verify the plasma generation and expansion through the ultrahigh-speed photography; obtain measurements of temperature and density by spectroscopy (using an optical analyser of multichannels) and obtain measurements of kinetic energy of ions through his fly time, using a 'Faraday cup'. A vacuum system with an adsorption pump for pre-vacuum and ionic pump was used to reduce pressure and avoid mechanical vibrations and system contaminations. (M.C.K.) [pt

  7. Brillouin scatter in laser-produced plasmas

    International Nuclear Information System (INIS)

    Phillion, D.W.; Kruer, W.L.; Rupert, V.C.

    1977-01-01

    The absorption of intense laser light is found to be reduced when targets are irradiated by 1.06 μm light with long pulse widths (150-400 psec) and large focal spots (100-250 μm). Estimates of Brillouin scatter which account for the finite heat capacity of the underdense plasma predict this reduction. Spectra of the back reflected light show red shifts indicative of Brillouin scattering

  8. Study of a Laser-Produced Plasma by Langmuir Probes

    DEFF Research Database (Denmark)

    Chang, C. T.; Hasimi, M.; Pant, H. C.

    1977-01-01

    -emission peak and the main plasma from the target. The flow velocity, density and electron temperature of the plasma were determined. The expansion of the plasma was found to be adiabatic, yielding gamma =5/3. The spatial distribution of the plasma was observed to be strongly anisotropic.......The structure, the parameters and the expansion of the plasma produced by focusing a 7 J, 20 ns Nd-glass laser on stainless-steel and glass targets suspended in a high-vacuum chamber were investigated by Langmuir probes. It was observed that the probe signals consisted of a photoelectric...

  9. Ion-Ion Plasmas Produced by Electron Beams

    Science.gov (United States)

    Fernsler, R. F.; Leonhardt, D.; Walton, S. G.; Meger, R. A.

    2001-10-01

    The ability of plasmas to etch deep, small-scale features in materials is limited by localized charging of the features. The features charge because of the difference in electron and ion anisotropy, and thus one solution now being explored is to use ion-ion plasmas in place of electron-ion plasmas. Ion-ion plasmas are effectively electron-free and consist mainly of positive and negative ions. Since the two ion species behave similarly, localized charging is largely eliminated. However, the only way to produce ion-ion plasmas at low gas pressure is to convert electrons into negative ions through two-body attachment to neutrals. While the electron attachment rate is large at low electron temperatures (Te < 1 eV) in many of the halogen gases used for processing, these temperatures occur in most reactors only during the afterglow when the heating fields are turned off and the plasma is decaying. By contrast, Te is low nearly all the time in plasmas produced by electron beams, and therefore electron beams can potentially produce ion-ion plasmas continuously. The theory of ion-ion plasmas formed by pulsed electron beams is examined in this talk and compared with experimental results presented elsewhere [1]. Some general limitations of ion-ion plasmas, including relatively low flux levels, are discussed as well. [1] See the presentation by D. Leonhardt et al. at this conference.

  10. Interaction of two plasma jets produced successively from Cu target

    Czech Academy of Sciences Publication Activity Database

    Kasperczuk, A.; Pisarczyk, T.; Badziak, J.; Borodziuk, S.; Chodukowski, T.; Parys, P.; Ullschmied, Jiří; Krouský, Eduard; Mašek, Karel; Pfeifer, Miroslav; Rohlena, Karel; Skála, Jiří; Pisarczyk, P.

    2010-01-01

    Roč. 28, č. 3 (2010), s. 497-504 ISSN 0263-0346 R&D Projects: GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z10100523 Keywords : Laser targets * laser produced-plasma jets * interaction of plasma jets * PALS laser Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.656, year: 2010

  11. Nanosized lithium titanates produced by plasma technique

    International Nuclear Information System (INIS)

    Grabis, J; Orlovs, A; Rasmane, Dz

    2007-01-01

    The synthesis of nanosized lithium titanates is studied by evaporation of coarse grained commercially available titanium and lithium carbonate particles in radio-frequency plasma flow with subsequent controlling formation and growth conditions of product particles. In accordance with the XRD analysis the phase composition of the obtained powders is determined by feeding rate of precursors and strongly by ratio of lithium and titanium. The Li 2 TiO 3 and Li 4 Ti 5 O 12 particles containing small amounts of extra phases were obtained at ratio of Li/Ti = 2 and Li/Ti = 0.8 respectively, feeding rate of precursors being in the range of 0.6-0.9 kg/h. Specific surface area of powders is in the range of 20-40 m2/g depending on concentration of vapours in gas flow and cooling rate of the products. Additional calcination of nanosize particles at 800-900 deg. C improves phase composition of lithium titanates

  12. Simulation of radiation in laser produced plasmas

    Science.gov (United States)

    Colombant, D. G.; Klapisch, M.; Deniz, A. V.; Weaver, J.; Schmitt, A.

    1999-11-01

    The radiation hydrodynamics code FAST1D(J.H.Gardner,A.J.Schmitt,J.P.Dahlburg,C.J.Pawley,S.E.Bodner,S.P.Obenschain,V.Serlin and Y.Aglitskiy,Phys. Plasmas,5,1935(1998)) was used directly (i.e. without postprocessor) to simulate radiation emitted from flat targets irradiated by the Nike laser, from 10^12 W/cm^2 to 10^13W/cm^2. We use enough photon groups to resolve spectral lines. Opacities are obtained from the STA code(A.Bar-Shalom,J.Oreg,M.Klapisch and T.Lehecka,Phys.Rev.E,59,3512(1999)), and non LTE effects are described with the Busquet model(M.Busquet,Phys.Fluids B,5,4191(1993)). Results are compared to transmission grating spectra in the range 100-600eV, and to time-resolved calibrated filtered diodes (spectral windows around 100, 180, 280 and 450 eV).

  13. 3-D magnetic reconnection in colliding laser-produced plasmas

    Science.gov (United States)

    Matteucci, Jackson; Fox, Will; Moissard, Clement; Bhattacharjee, Amitava

    2017-10-01

    Recent experiments have demonstrated magnetic reconnection between colliding plasma plumes, where the reconnecting magnetic fields were self-generated in the expanding laser-produced plasmas by the Biermann battery effect. Using fully kinetic 3-D particle in cell simulations, we conduct the first end-to-end simulations of these experiments, including self-consistent magnetic field generation via the Biermann effect through driven magnetic field reconnection. The simulations show rich, temporally and spatially dependent magnetic field reconnection. First, we find fast, vertically-localized ``Biermann-mediated reconnection,'' an inherently 3-D reconnection mechanism where the sign of the Biermann term reverses in the reconnection layer, destroying incoming flux and reconnecting flux downstream. Reconnection then transitions to fast, collisionless reconnection sustained by the non-gyrotropic pressure tensor. To separate out the role 3-D mechanisms, 2-D simulations are initialized based on reconnection-plane cuts of the 3-D simulations. These simulations demonstrate: (1) suppression of Biermann-mediated reconnection in 2-D; (2) similar efficacy of pressure tensor mechanisms in 2-D and 3-D; and (3) plasmoids develop in the reconnection layer in 2-D, where-as they are suppressed in 3-D. Supported by NDSEG Fellowship. This research used resources of the OLCF at ORNL, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725.

  14. Stationary Density Variation Produced by a Standing Plasma Wave

    DEFF Research Database (Denmark)

    Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens

    1977-01-01

    Measurements are presented of a stationary density modulation produced by a standing electron plasma wave. The experimental results are well explained by taking into account the ponderomotive forces on the electrons exerted by the high frequency field.......Measurements are presented of a stationary density modulation produced by a standing electron plasma wave. The experimental results are well explained by taking into account the ponderomotive forces on the electrons exerted by the high frequency field....

  15. Optimization for getting stable plasma initiation in JT-60

    International Nuclear Information System (INIS)

    Yoshino, Ryuji; Neyatani, Yuzuru; Abe, T.

    1988-06-01

    This paper analyses the plasma current build-up just after the breakdown, and investigates the method for obtaining more stable plasma initiation with reduced Volt-second consumption. Control of the amount of particles contained in the wall is necessary for getting the optimum plasma density just after the breakdown, and is essential for obtaining the stable current build-up. (author)

  16. Electrostatic fields and charged particle acceleration in laser produced plasmas

    International Nuclear Information System (INIS)

    Hora, H.

    1983-01-01

    Some new aspects pioneered recently by Alfven in the theory of cosmic plasmas, indicate the possibility of a new treatment of the action of electrostatic double layers in the periphery of an expanding laser produced plasma. The thermally produced electrostatic double layer which has been re-derived for a homogeneous plasma shows that a strong upshift of ion energies is possible, in agreement with experiments. The number of accelerated ions is many orders of magnitude smaller than observed at keV and MeV energies. The nonlinear force acceleration could explain the number and energy of the observed fast ions. It is shown, however, that electrostatic double layers can be generated which should produce super-fast ions. A derivation of the spread double layers in the case of inhomogeneous plasmas is presented. It is concluded that the hydrodynamically expected multi GeV heavy ions for 10 TW laser pulses should produce super-fast ions up to the TeV range. Further conclusions are drawn from the electrostatically measured upshifted (by 300 keV) DT fusion alphas from laser compressed plasma. An analysis of alpha spectra attempts to distinguish between different models of the stopping power in the plasmas. The analysis preliminarily arrives at a preference for the collective model. (author)

  17. EUV laser produced and induced plasmas for nanolithography

    Science.gov (United States)

    Sizyuk, Tatyana; Hassanein, Ahmed

    2017-10-01

    EUV produced plasma sources are being extensively studied for the development of new technology for computer chips production. Challenging tasks include optimization of EUV source efficiency, producing powerful source in 2 percentage bandwidth around 13.5 nm for high volume manufacture (HVM), and increasing the lifetime of collecting optics. Mass-limited targets, such as small droplet, allow to reduce contamination of chamber environment and mirror surface damage. However, reducing droplet size limits EUV power output. Our analysis showed the requirement for the target parameters and chamber conditions to achieve 500 W EUV output for HVM. The HEIGHTS package was used for the simulations of laser produced plasma evolution starting from laser interaction with solid target, development and expansion of vapor/plasma plume with accurate optical data calculation, especially in narrow EUV region. Detailed 3D modeling of mix environment including evolution and interplay of plasma produced by lasers from Sn target and plasma produced by in-band and out-of-band EUV radiation in ambient gas, used for the collecting optics protection and cleaning, allowed predicting conditions in entire LPP system. Effect of these conditions on EUV photon absorption and collection was analyzed. This work is supported by the National Science Foundation, PIRE project.

  18. Stark broadening in hot, dense laser-produced plasmas

    International Nuclear Information System (INIS)

    Tighe, R.J.; Hooper, C.F. Jr.

    1976-01-01

    Broadened Lyman-α x-ray lines from neon X and argon XVIII radiators, which are immersed in a hot, dense deuterium or deuterium-tritium plasma, are discussed. In particular, these lines are analyzed for several temperature-density cases, characteristic of laser-produced plasmas; special attention paid to the relative importance of ion, electron, and Doppler effects. Static ion microfield distribution functions are tabulated

  19. Magnetic confinement of laser produced LiH plasma in LITE

    International Nuclear Information System (INIS)

    Ard, W.B.; Stufflebeam, J.H.; Tomlinson, R.G.

    1976-01-01

    In the LITE experiment, a hot, dense plasma produced by laser heating of an approximately 100 μ dia LiH particle is used to fill a minimum-B baseball coil mirror magnetic containment field. The confined laser produced plasma subsequently serves as the target for an energetic neutral hydrogen beam in experiments to investigate the target plasma buildup approach for creating and sustaining an equilibrium, steady state mirror fusion plasma. In the experiments, the LiH particle is positioned in vacuum at the laser beam focus by a feedback particle suspension system and heated by two sided irradiation with the focused dual beam, 50 j, 7 nsec output of a Q-switched Nd-glass laser. The energy density of the laser produced plasma is initially much greater than that of the surrounding magnetic field and the plasma expands, converting its internal energy into expansion kinetic energy and displacement of the magnetic field. As the energy density falls below that of the magnetic field, the expansion is stopped and the plasma becomes trapped, making the transition to a low beta, mirror confined plasma. This report is concerned with the properties and behavior of the plasma in the confinement stage

  20. Studies on fundamental technologies for producing tokamak-plasma

    International Nuclear Information System (INIS)

    Matsuzaki, Yoshimi

    1987-10-01

    The report describes studies on fundamental technologies to produce tokamak-plasma of the JFT-2 and JFT-2M tokamaks. (1) In order to measure the particle number of residual gases, calibration methods of vacuum gauges have been developed. (2) Devices for a Taylor-type discharge cleaning (TDC), a glow discharge cleaning (GDC) and ECR discharge cleaning (ECR-DC) have been made and the cleaning effects have been investigated. In TDC the most effective plasma for cleaning is obtained in the plasma with 5 eV of electron temperature. GDC is effective in removing carbon impurities, but is less effective for removing oxygen impurities. ECR-DC has nearly the similar effect as TDC. The cleaning effect of these three types were studied by comparing the properties of resulting tokamak plasmas in the JFT-2M tokamak. (3) Experimental studies of pre-ionization showed as following results; A simple pre-ionization equipment as a hot-electron-gun and a J x B gun was effective in reducing breakdown voltage. An ordinary mode wave of the electron cyclotron frequency was very effective for pre-ionization. The RF power whose density is 3.6 x 10 -2 W/cm 3 produced plasma of an electron density of 5 x 10 11 cm -3 . In this case, it is possible to start up with negligible consumption of the magnetic flux caused by the plasma resistance. (4) Concerning to studies on plasma control, the following results were obtained; In order to obtain constant plasma current, a pulse forming network was constructed and sufficient constant plasma current was achieved. In applying an iso-flux method for measuring the plasma position, it is no problem practically to use only one loop-coil and one magnetic probe. (author)

  1. Laser optically pumped by laser-produced plasma

    International Nuclear Information System (INIS)

    Silfvast, W.T.; Wood, O.R. II.

    1975-01-01

    Laser solids, liquids and gases are pumped by a new technique in which the output from an efficient molecular laser, such as a CO 2 laser, ionizes a medium, such as xenon, into a generally cylindrical plasma volume, in proximity to the pumped laser body. Breakdown yields a visible and ultraviolet-radiation-emitting plasma in that volume to pump the laser body. The spectral radiance of the plasma is significantly higher than that produced by a dc-discharge-heated plasma at nearly all wavelengths in the plasma spectrum. The risetime of radiation from the laser-produced plasma can also be significantly shorter than that of a dc heated plasma. A further advantage resides in the fact that in some applications the attenuating walls needed by flashlamps may be eliminated with the result that laser threshold is more readily reached. Traveling wave excitation may be provided by oblique incidence of the pumping laser beam through the ionizable medium to create sequential ionization of portions of that medium along the length of the pumped laser body. (auth)

  2. Physics and applications of plasmas produced by pulsed power technology

    International Nuclear Information System (INIS)

    Ozaki, Tetsuo; Katsuki, Sunao

    2013-10-01

    The papers presented at the symposium on 'Physics and Applications of Plasmas Produced by Pulsed Power Technology' held on March 27-28, 2012 at the National Institute for Fusion Science are collected in these proceedings. The papers in these proceedings reflect the current status and progress in the experimental and theoretical research on high power particle beams and high energy density plasmas produced by pulsed power technology. This issue is the collection of 22 papers presented at the entitled meeting. Ten of the presented papers are indexed individually. (J.P.N.)

  3. THE KINETICS OF METHYL METHACRYLATE POLYMERIZATION INITIATED BY THE VOLATILE PRODUCTS OF A METHYL METHACRYLATE PLASMA

    Institute of Scientific and Technical Information of China (English)

    杨梅林; 马於光; 郑莹光; 沈家骢

    1990-01-01

    It is found that the volatile products of methyl methacrylate plasma can very actively initiate the polymerization of the monomer to produce ultrahigh molecular weight polymers. This polymerization of MMA occurs by a livlng free radical mechanism with instantaneous initiation and monomer transfer.

  4. Collimation of laser-produced plasmas using axial magnetic field

    Czech Academy of Sciences Publication Activity Database

    Roy, Amitava; Harilal, S.S.; Hassan, S.M.; Endo, Akira; Mocek, Tomáš; Hassanein, A.

    2015-01-01

    Roč. 33, č. 2 (2015), s. 175-182 ISSN 0263-0346 R&D Projects: GA MŠk ED2.1.00/01.0027; GA MŠk EE2.3.20.0143; GA MŠk EE2.3.30.0057 Grant - others:HILASE(XE) CZ.1.05/2.1.00/01.0027; OP VK 6(XE) CZ.1.07/2.3.00/20.0143; OP VK 4 POSTDOK(XE) CZ.1.07/2.3.00/30.0057 Institutional support: RVO:68378271 Keywords : laser-produced plasma * optical emission spectroscopy * plasma-B field interaction * plasma temperature and density * tin plasma Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 1.649, year: 2015

  5. XUV laser-produced plasma sheet beam and microwave agile mirror

    International Nuclear Information System (INIS)

    Shen, W.; Scharer, J.E.; Porter, B.; Lam, N.T.

    1994-01-01

    An excimer-laser (λ = 193 nm) produced plasma in an organic gas (TMAE) has been generated and studied. These studies have determined the ion-electron recombination coefficient and the photon absorption cross-section, of the neutral gas. The dependences of wave transmission, reflection and absorption on plasma density are obtained. A new optical system with an array of cylindrical XUV coated lenses has been implemented to form a plasma sheet to study its usage as agile mirror microwave reflector. The lens system expands the incident laser beam in X direction and compresses it in Y direction to form a sheet beam. The expanded beam then passes through a vacuum chamber filled with TMAE at 50--500 nTorr to produce the plasma sheet. Space-time measurements of the plasma density and temperature as measured by a Langmuir probe are presented. XUV optical measurements of the laser beam as measured by a photodiode are presented. Initial experiments have generated a plasma sheet of 5--10 mm x 11 cm with peak plasma density of 5 x 10 13 cm -3 . A microwave source will be utilized to study the agile mirror character of the plasma sheet. Modeling of the microwave reflection from the plasma profile will also be discussed

  6. Study of charged fusion products in laser produced plasmas

    International Nuclear Information System (INIS)

    Rosenblum, M.

    1981-07-01

    Charged reaction products play a central role in inertial confinement fusion. The investigation of the various processes these particles undergo in laser produced plasmas, their influence on the dynamics of the fusion and their utilization as a diagnostic tool are the main subjects of this thesis. (author)

  7. Plasma androgen concentrations in initial samples from spotted ...

    African Journals Online (AJOL)

    1990-01-31

    Jan 31, 1990 ... initial samples, the immobilization stress response and the response to exogenous GnRH administration, for ... the sex-specific differences in plasma androgens is confounded by other variables such as the reproductive.

  8. Suitability of tunneling ionization produced plasmas for the plasma beat wave accelerator

    International Nuclear Information System (INIS)

    Leeman, W.P.; Clayton, C.E.; Marsh, K.A.; Dyson, A.; Joshi, C.

    1991-01-01

    Tunneling ionization can be thought of as the high intensity, low frequency limit of multi-photon ionization (MPI). Extremely uniform plasmas were produced by the latter process at Rutherford lab for beat wave excitation experiments using a 0.5 μm laser. Plasmas with 100% ionization were produced with densities exceeding 10 17 cm -3 . The experiment uses a CO 2 laser (I max ∼ 5 x 10 14 W/cm 2 ) which allows the formation of plasmas via the tunneling process. For the experiments the authors need plasmas with densities in the range of 5 to 10 x 10 16 cm -3 . Using Thomson scattering as a diagnostic they have explored the density and temperature regime of tunneling ionization produced plasmas. They find that plasmas with densities up to 10 16 cm -3 can indeed be produced and that these plasmas are hot. Beyond this density strong refraction of laser radiation occurs due to the radial profile of the plasma. Implications of this work to the Beat Wave Accelerator program will be discussed

  9. High resolution X-ray spectromicroscopy of laser produced plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Faenov, A.Ya. [Multi-charged Ions Spectra Data Center of VNIIFTRI (MISDC), Mendeleevo, Moscow region, (Russian Federation)

    2000-01-01

    In recent years new classes of X-ray spectroscopic instruments possessing both dispersive and focusing properties have been manufactured. Their principal advantage over more traditional instruments is that they combine very high luminosity with high spatial resolution, while preserving the highest possible spectral resolution of their dispersive elements. These instruments opened up the registration of plasmas in new regimes and surroundings. The measurements delivered new information about the properties of even previously studied traditional plasma objects (e.g. ns-laser produced plasmas). Also the detailed investigation of relatively new plasma laboratory sources with very small dimensions and low energy content (e.g. mJ fs-laser pulses) became possible. The purpose of this report is to give a short review of the experimental and theoretical results obtained in the past few years by MISDC (Multi-charged Ions Spectra Data Center) research team in the field of X-ray spectroscopy of a laser-produced plasma. Experimental spectra have been obtained at various laser installations with nanosecond, sub-nanosecond, picosecond and sub-picosecond pulses interacting with solid, gaseous or cluster targets in collaborations with research teams from Russia, USA, Germany, France, Poland, Belgium, Italy, China and Israel. Practically all results have been obtained with the help of spectrographs with spherically bent mica crystals operating in FSSR-1D, 2D schemes. (author)

  10. Experimental and theoretical investigation of radiation and dynamics properties in laser-produced carbon plasmas

    Science.gov (United States)

    Min, Qi; Su, Maogen; Wang, Bo; Cao, Shiquan; Sun, Duixiong; Dong, Chenzhong

    2018-05-01

    The radiation and dynamics properties of laser-produced carbon plasma in vacuum were studied experimentally with aid of a spatio-temporally resolved emission spectroscopy technique. In addition, a radiation hydrodynamics model based on the fluid dynamic equations and the radiative transfer equation was presented, and calculation of the charge states was performed within the time-dependent collisional radiative model. Detailed temporal and spatial evolution behavior about plasma parameters have been analyzed, such as velocity, electron temperature, charge state distribution, energy level population, and various atomic processes. At the same time, the effects of different atomic processes on the charge state distribution were examined. Finally, the validity of assuming a local thermodynamic equilibrium in the carbon plasma expansion was checked, and the results clearly indicate that the assumption was valid only at the initial (applicable near the plasma boundary because of a sharp drop of plasma temperature and electron density.

  11. New approach to controlling impurity contamination of a plasma-gun-produced compact torus

    International Nuclear Information System (INIS)

    Post, R.F.; Turner, W.C.

    1982-01-01

    The presence of impurity ions, notably carbon and oxygen, has been determined to be a major factor limiting the lifetime of field-reversed plasma entities produced by coaxial plasma guns such as the Beta II gun at LLNL. Similar problems are encountered in other toroidal plasmas, e.g. those in tokamaks. However, the solution employed there, discharge cleaning, followed by initiation of the plasma at low density (where impurity radiation losses are exceeded by ohmic heating rates) is not applicable here. This note discusses a proposed means for drastically reducing the level of impurities. (These are believed to be evolved from the gun electrode surfaces as a result of thermal shock associated with UV emission from the gun plasma). The idea: take advantage of the UV pulse preferentially to release hydrogen from the electrode surfaces. These surfaces are to be coated with a few-micron-thick layer of titanium, outgassed by preheating and subsequently loaded with hydrogen

  12. High plasma rotation velocity and density transitions by biased electrodes in RF produced, magnetized plasma

    International Nuclear Information System (INIS)

    Matsuyama, Shoichiro; Shinohara, Shunjiro

    2001-01-01

    A large density profile modification was successfully obtained by voltage biasing to electrodes inserted in a RF (radio frequency) produced, magnetized plasma, and formation of strong shear of azimuthal plasma rotation velocity in a supersonic regime was found. For the case of biasing to an electrode near the central plasma region, two types of density transitions were observed in the outer plasma region: one was an oscillatory transition between two states, and the other was a transition from high to low density states with a large reduction of density fluctuations. (author)

  13. High plasma rotation velocity and density transitions by biased electrodes in RF produced, magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Matsuyama, Shoichiro; Shinohara, Shunjiro [Kyushu Univ., Interdisciplinary Graduate School of Engineering Sciences, Fukuoka (Japan)

    2001-07-01

    A large density profile modification was successfully obtained by voltage biasing to electrodes inserted in a RF (radio frequency) produced, magnetized plasma, and formation of strong shear of azimuthal plasma rotation velocity in a supersonic regime was found. For the case of biasing to an electrode near the central plasma region, two types of density transitions were observed in the outer plasma region: one was an oscillatory transition between two states, and the other was a transition from high to low density states with a large reduction of density fluctuations. (author)

  14. Laser-pulsed Plasma Chemistry: Laser-initiated Plasma Oxidation Of Niobium

    OpenAIRE

    Marks R.F.; Pollak R.A.; Avouris Ph.; Lin C.T.; Thefaine Y.J.

    1983-01-01

    We report the first observation of the chemical modification of a solid surface exposed to an ambient gas plasma initiated by the interaction of laser radiation with the same surface. A new technique, which we designate laser-pulsed plasma chemistry (LPPC), is proposed for activating heterogeneous chemical reactions at solid surfaces in a gaseous ambient by means of a plasma initiated by laser radiation. Results for niobium metal in one atmosphere oxygen demonstrate single-pulse, self-limitin...

  15. Initial damage processes for diamond film exposure to hydrogen plasma

    International Nuclear Information System (INIS)

    Deslandes, A.; Guenette, M.C.; Samuell, C.M.; Karatchevtseva, I.; Ionescu, M.; Cohen, D.D.; Blackwell, B.; Corr, C.; Riley, D.P.

    2013-01-01

    Graphical abstract: -- Highlights: • Exposing chemical vapour deposited (CVD) diamond films in a recently constructed device, MAGPIE, specially commissioned to simulate fusion plasma conditions. • Non-diamond material is etched from the diamond. • There is no hydrogen retention observed, which suggests diamond is an excellent candidate for plasma facing materials. • Final structure of the surface is dependent on synergistic effects of etching and ion-induced structural change. -- Abstract: Diamond is considered to be a possible alternative to other carbon based materials as a plasma facing material in nuclear fusion devices due to its high thermal conductivity and resistance to chemical erosion. In this work CVD diamond films were exposed to hydrogen plasma in the MAGnetized Plasma Interaction Experiment (MAGPIE): a linear plasma device at the Australian National University which simulates plasma conditions relevant to nuclear fusion. Various negative sample stage biases of magnitude less than 500 V were applied to control the energies of impinging ions. Characterisation results from SEM, Raman spectroscopy and ERDA are presented. No measureable quantity of hydrogen retention was observed, this is either due to no incorporation of hydrogen into the diamond structure or due to initial incorporation as a hydrocarbon followed by subsequent etching back into the plasma. A model is presented for the initial stages of diamond erosion in fusion relevant hydrogen plasma that involves chemical erosion of non-diamond material from the surface by hydrogen radicals and damage to the subsurface region from energetic hydrogen ions. These results show that the initial damage processes in this plasma regime are comparable to previous studies of the fundamental processes as reported for less extreme plasma such as in the development of diamond films

  16. Production of a rapidly rotating plasma by cross-field injection of gun-produced plasma

    International Nuclear Information System (INIS)

    Ohzu, Akira; Ikehata, Takashi; Tanabe, Toshio; Mase, Hiroshi

    1984-01-01

    Cross-field plasma injection with use of a JxB plasma gun is described as a method to produce rapidly rotating plasma in a crossed electric and magnetic field system. The rotational velocity of the plasma is seriously limited by neutrals surrounding the plasma through strong interactions at the boundary layer. The concentration of neutrals can be reduced by the injection of fully or partially ionized plasma into the discharge volume instead of filling the volume with an operating gas. With use of this method, it is observed that the rotational velocity increases by a factor of 2 to 3 when compared with the conventional method of stationary gas-filling. (author)

  17. Ramp-up of CHI Initiated Plasmas on NSTX

    International Nuclear Information System (INIS)

    Mueller, D.; Bell, M.G.; Bell, R.E.; LeBlanc, B.; Roquemore, A.L.; Raman, R.; Jarboe, T.R.; Nelson, B.A.; Soukhanovskii, V.

    2009-01-01

    Experiments on the National Spherical Torus (NSTX) have now demonstrated flux savings using transient coaxial helicity injection (CHI). In these discharges, the discharges initiated by CHI are ramped up with an inductive transformer and exhibit higher plasma current than discharges without the benefit of CHI initiation.

  18. Instabilities observed at the bubble edge of a laser produced plasma during its expansion in an ambient tenuous plasma

    Science.gov (United States)

    Lee, Bo Ram; Clark, S. E.; Hoffmann, D. H. H.; Niemann, C.

    2014-10-01

    The Raptor kJ class 1053 nm Nd:Glass laser in the Phoenix laser laboratory at University of California, Los Angeles, is used to ablate a dense debris plasma from a graphite or plastic target embedded in a tenuous, uniform, and quiescent ambient magnetized plasma in the Large Plasma Device (LAPD) which provides a peak plasma density of ni ~ 1013 cm-3. Its background magnetic field can vary between 200 and 1200 G. Debris ions from laser produced plasma expand out conically with super-Alfvénic speed (MA ~ 2) and expel the background magnetic field and ambient ions to form a diamagnetic bubble. The debris plasma interacts with the ambient plasma and the magnetic field and acts as a piston which can create collisionless shocks. Flute-type instabilities, which are probably large Larmor radius Rayleigh Taylor instabilities or lower hybrid drift instabilities, are developed at the bubble edge and also observed in the experiment. The amplitude and wavelength dependence of the instabilities, which might be a strong function of debris to ambient mass to charge ratio, is studied and the experimental results are compared to the two dimensional hybrid simulations. the Deutsche Forschungsgemeinschaft in the framework of the Excellence Initiative Darmstadt Graduate School of Energy Science and Engineering (GSC1070).

  19. Centrifugal mass separation in rotating plasmas produced by a coaxial plasma gun

    International Nuclear Information System (INIS)

    Ikehata, T.; Suzuki, M.; Tanabe, T.; Mase, H.

    1989-01-01

    Rotating Cu/Zn plasmas produced by a coaxial plasma gun have been applied to plasma centrifuge. A separation factor of up to 10 is measured over a radius of 4 cm when a current of 13 kA and an axial magnetic field of 2.5 kG are applied. Plasma parameters are: rotation frequency ω=1.1x10 6 rad/s, density n∼10 15 cm -3 , and ion temperature T i =10 eV. The separation factor of 2 is attained even in the plasma core where the density is higher than one-half of the peak value. This is attributed to the fact that a strong centrifugal force forms a hollow density profile which gives the density peak at a radius of 2 cm

  20. Optical emission spectra of a copper plasma produced by a metal vapour vacuum arc plasma source

    International Nuclear Information System (INIS)

    Yotsombat, B.; Poolcharuansin, P.; Vilaithong, T.; Davydov, S.; Brown, I.G.

    2001-01-01

    Optical emission spectroscopy in the range 200-800 nm was applied for investigation of the copper plasma produced by a metal vapour vacuum arc plasma source. The experiments were conducted for the cases when the plasma was guided by straight and Ω-shaped curved solenoids as well as without solenoids, and also for different vacuum conditions. It was found that, besides singly- and doubly-charged ions, a relatively high concentration of excited neutral copper atoms was present in the plasma. The relative fraction of excited atoms was much higher in the region close to the cathode surface than in the plasma column inside the solenoid. The concentration of excited neutral, singly- and doubly-ionized atoms increased proportionally when the arc current was increased to 400 A. Some weak lines were attributed to more highly ionized copper species and impurities in the cathode material. (author)

  1. Ionization mechanism of cesium plasma produced by irradiation of dye laser

    International Nuclear Information System (INIS)

    Yamada, Jun; Shibata, Kohji; Uchida, Yoshiyuki; Hioki, Yoshiaki; Sahashi, Toshio.

    1992-01-01

    When a cesium vapor was irradiated by a dye laser which was tuned to the cesium atomic transition line, the number of charged particles produced by the laser radiation was observed. Several sharp peaks in the number of charged particles were observed, which corresponded to the atomic transition where the lower level was the 6P excited atom. The ionization mechanism of the laser-produced cesium plasma has been discussed. An initial electron is produced by laser absorptions of the cesium dimer. When the cesium density is high, many 6P excited atoms are excited by electron collisions. The 6P excited atom further absorbs the laser photon and is ionized through the higher-energy state. As the cesium vapor pressure increases, the resonance effect becomes observable. The 6P excited atom plays dominant role in the ionization mechanism of the laser-produced cesium plasma. (author)

  2. Line intensities for diagnosing laser-produced plasmas

    International Nuclear Information System (INIS)

    Kauffman, R.L.; Matthews, D.L.; Lee, R.W.; Whitten, B.L.; Kilkenny, J.D.

    1983-01-01

    We have measured relative line intensities of the K x-ray spectra of Si, Cl, and Ca from laser-produced plasmas to assess their usefulness as a plasma diagnostic. The different elements are added at low concentrations to CH disks which are irradiated at 5 x 10 14 W/cm 2 with a 0.53 μm laser pulse of 20 Joules at 1 nsec. The concentration of each element is kept low in order not to change the Z of the plasma, and therefore the plasma dynamics. The various spectra are measured with a time-resolved spectrograph to obtain line intensities as a function of time over the length of the laser pulse. These relative intensities of various He-like and H-like lines are compared with calculations from a steady-state level population code. The results give good consistency among the various line ratios. Agreement is not as good for analysis of the Li-like satellite lines. Modelling of the Li-like lines need further investigation. 10 references, 9 figures

  3. Transition from isentropic to isothermal expansion in laser produced plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Barrero, A; Santartin, J R

    1980-07-01

    The transition that the expansion flow of laser-produced plasmas experiences when ones moves from long, low intensity pulses (temperature vanishing at the Isentropic plasma-vacuum front, lying at finite distance) to short, intense ones (non-zero, uni- form temperature at the plasma-vacuum front, lying at infinity) is studied. For planar geometry and large Ion number Z{sub j} the transition occurs for d {phi} / d t {approx_equal} 0.14(27/8)k{sup 7}/2 Z{sub j}{sup 3}/2/m{sub j}{sup 3}/2 K; {phi}, k, m{sub j}, and K are laser intensity, Boltzmann s constant, ion mass, and Spitzer s heat conduction coefficient. This result remains valid for finite Z{sub j} though the numerical factor in d{phi} / d t is different. In spherical geometry a similar transition occurs even in steady conditions. Shorter wavelength lasers and higher Z{sub j} plasmas allow faster rising pulses below transition. (Author) 13 refs.

  4. Polarization spectroscopy on laser-produced plasmas and Z-pinch plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong E. [POSTECH, Kyungbuk (Korea); Baronova, Elena O. [RRC Kurchatov Institute, Nuclear Fusion Institute, Moscow (Russian Federation); Jakubowski, Lech [Soltan Institute for Nuclear Studies, Swierk-Otwock (Poland)

    2002-08-01

    PPS experiments on laser-produced plasmas are reviewed. Polarization is interpreted in terms of the anisotropic velocity distribution of electrons due to non-local transport. The polarization of an x-ray laser, and recent results regarding the recombining plasma are also presented. X-ray polarization spectroscopy experiments on heliumlike ion lines from a vacuum spark and from a plasma focus are presented: in both cases, the resonance line of the heliumlike ions shows polarization in the direction perpendicular to the discharge axis. Two possible interpretations are suggested. (author)

  5. Interaction of a laser-produced copper plasma jet with ambient plastic plasma

    Czech Academy of Sciences Publication Activity Database

    Kasperczuk, A.; Pisarczyk, T.; Badziak, J.; Borodziuk, S.; Chodukowski, T.; Gus’kov, S.Yu.; Demchenko, N. N.; Klir, D.; Kravarik, J.; Kubes, P.; Rezac, K.; Ullschmied, Jiří; Krouský, Eduard; Mašek, Karel; Pfeifer, Miroslav; Rohlena, Karel; Skála, Jiří; Pisarczyk, P.

    2011-01-01

    Roč. 53, č. 9 (2011), 095003-095003 ISSN 0741-3335 R&D Projects: GA MŠk(CZ) 7E09092; GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z10100523 Keywords : laser produced-plasma jets * PALS laser * laser ablation * copper plasma * plastic plasma Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.425, year: 2011 http://iopscience.iop.org/0741-3335/53/9/095003/pdf/0741-3335_53_9_095003.pdf

  6. Hydrodynamic simulation of X-UV laser-produced plasmas

    International Nuclear Information System (INIS)

    Fajardo, M.; Zeitoun, P.; Gauthier, J.C.

    2004-01-01

    With the construction of novel X-UV sources, such as V-UV FEL's (free-electron lasers), X-UV laser-matter interaction will become available at ultra-high intensities. But even table-top facilities such as X-UV lasers or High Harmonic Generation, are starting to reach intensities high enough to produce dense plasmas. X-UV laser-matter interaction is studied by a 1-dimensional hydrodynamic Lagrangian code with radiative transfer for a range of interesting X-UV sources. Heating is found to be very different for Z=12-14 elements having L-edges around the X-UV laser wavelength. Possible absorption mechanisms were investigated in order to explain this behaviour, and interaction with cold dense matter proved to be dominant. Plasma sensitivity to X-UV laser parameters such as energy, pulse duration, and wavelength was also studied, covering ranges of existing X-UV lasers. We found that X-UV laser-produced plasmas could be studied using table-top lasers, paving the way for future V-UV-FEL high intensity experiments. (authors)

  7. Radiofrequency initiation and radiofrequency sustainment of laser initiated seeded high pressure plasma

    International Nuclear Information System (INIS)

    Paller, Eric S.; Scharer, John E.; Akhtar, Kamran; Kelly, Kurt; Ding, Guowen

    2001-01-01

    We examine radiofrequency initiation of high pressure(1-70 Torr) inductive plasma discharges in argon, nitrogen, air and organic seed gas mixtures. Millimeter wave interferometry, optical emission and antenna wave impedance measurements for double half-turn helix and helical inductive antennas are used to interpret the rf/plasma coupling, measure the densities in the range of 10 12 cm -3 and analyze the ionization and excited states of the gas mixtures. We have also carried out 193 nm excimer laser initiation of an organic gas seed plasma which is sustained at higher pressures(150 Torr) by radiofrequency coupling at 2.8 kW power levels

  8. Spectra of neutrons and fusion charged products produced in a dense laser plasma

    International Nuclear Information System (INIS)

    Burtsev, V.A.; Dyatlov, V.D.; Krzhizhanovskij, R.E.; Levkovskij, A.A.

    1977-01-01

    The possibility of laser-produced plasma diagnostics has been investigated by measuring spectra of neutrons and alpha particles produced in the T(d,n) 4 He reaction. Using the Monte Carlo method the spectra have been calculated for nine states of the deuterium-tritium plasma with the temperature of 1;5 and 10 keV and the density of 0.2; 1 and 10 g/cm 3 respectively. The initial radius of the target was assumed to be 0.01 cm at the density of 0.2 g/cm 3 . It is shown that the neutron and alpha spectra can serve as plasma diagnostics parameters in laser fusion

  9. Recent developments in understanding the physics of laser produced plasmas

    International Nuclear Information System (INIS)

    Bezzerides, B.; DuBois, D.F.; Forslund, D.W.; Kindel, J.M.; Lee, K.; Lindman, E.L.

    1976-01-01

    The absorption of intense laser light by a plasma is known to produce a high energy component of electrons. Even though the hot electron pressure may be larger than the cold background pressure, the background temperature can control the self-consistent profile modification. Since temperatures in high intensity experiments seem to be similar for CO 2 and Nd glass lasers, the profile modification may be so severe for CO 2 and Nd glass lasers, the profile modification may be so severe for CO 2 that orders of magnitude change in density can occur over microns, leading to a softened electron spectrum. However, the resulting equilibrium of laser pressure balancing plasma pressure is unstable even when flow is properly taken into account. We also briefly discuss recent results for self-generated magnetic fields including important kinetic effects

  10. Analysis of extreme ultraviolet spectra from laser produced rhenium plasmas

    Science.gov (United States)

    Wu, Tao; Higashiguchi, Takeshi; Li, Bowen; Suzuki, Yuhei; Arai, Goki; Dinh, Thanh-Hung; Dunne, Padraig; O'Reilly, Fergal; Sokell, Emma; Liu, Luning; O'Sullivan, Gerry

    2015-08-01

    Extreme ultraviolet spectra of highly-charged rhenium ions were observed in the 1-7 nm region using two Nd:YAG lasers with pulse lengths of 150 ps and 10 ns, respectively, operating at a number of laser power densities. The maximum focused peak power density was 2.6 × 1014 W cm-2 for the former and 5.5 × 1012 W cm-2 for the latter. The Cowan suite of atomic structure codes and unresolved transition array (UTA) approach were used to calculate and interpret the emission properties of the different spectra obtained. The results show that n = 4-n = 4 and n = 4-n = 5 UTAs lead to two intense quasi-continuous emission bands in the 4.3-6.3 nm and 1.5-4.3 nm spectral regions. As a result of the different ion stage distributions in the plasmas induced by ps and ns laser irradiation the 1.5-4.3 nm UTA peak moves to shorter wavelength in the ps laser produced plasma spectra. For the ns spectrum, the most populated ion stage during the lifetime of this plasma that could be identified from the n = 4-n = 5 transitions was Re23+ while for the ps plasma the presence of significantly higher stages was demonstrated. For the n = 4-n = 4 4p64dN-4p54dN+1 + 4p64dN-14f transitions, the 4d-4f transitions contribute mainly in the most intense 4.7-5.5 nm region while the 4p-4d subgroup gives rise to a weaker feature in the 4.3-4.7 nm region. A number of previously unidentified spectral features produced by n = 4-n = 5 transitions in the spectra of Re XVI to Re XXXIX are identified.

  11. Relative ion expansion velocity in laser-produced plasmas

    International Nuclear Information System (INIS)

    Goldsmith, S.; Moreno, J.C.; Griem, H.R.; Cohen, L.; Richardson, M.C.

    1988-01-01

    The spectra of highly ionized titanium, TiXIII through TiXXI, and CVI Lyman lines were excited in laser-produced plasmas. The plasma was produced by uniformly irradiating spherical glass microballoons coated with thin layers of titanium and parylene. The 24-beam Omega laser system produced short, 0.6 ns, and high intensity, 4 x 10 14 W/cm, 2 laser pulses at a wavelength of 351 nm. The measured wavelength for the 2p-3s TiXIII resonance lines had an average shift of +0.023 A relative to the CVI and TiXX spectral lines. No shift was found between the CVI, TiXIX, and TiXX lines. The shift is attributed to a Doppler effect, resulting from a difference of (2.6 +- 0.2) x 10 7 cm/s in the expansion velocities of TiXIX and TiXX ions compared to TiXIII ions

  12. Influence of the focal point position on the properties of a laser-produced plasma

    International Nuclear Information System (INIS)

    Kasperczuk, A.; Pisarczyk, T.; Badziak, J.; Miklaszewski, R.; Parys, P.; Rosinski, M.; Wolowski, J.; Stenz, CH.; Ullschmied, J.; Krousky, E.; Masek, K.; Pfeifer, M.; Rohlena, K.; Skala, J.; Pisarczyk, P.

    2007-01-01

    This paper deals with investigations of the influence of the focusing lens focal point position on the properties of a plasma produced by a defocused laser beam. The experiment was carried out at the Prague Asterix Laser System iodine laser [K. Jungwirth, A. Cejnarova, L. Juha, B. Kralikova, J. Krasa, E. Krousky, P. Krupickova, L. Laska, K. Masek, T. Mocek, M. Pfeifer, A. Prag, O. Renner, K. Rohlena, B. Rus, J. Skala, P. Straka, and J. Ullschmied, Phys. Plasmas 8, 2495 (2001)] by using the third harmonic of laser radiation (λ=0.438 μm), laser energy of 70 J, pulse duration of 250 ps (full width at half-maximum), and beam spot radii of 250 and 400 μm. Cu and Ta were chosen as target materials. The experimental data were obtained by means of a three-frame interferometric system, ion collectors, and crater replica techniques. The reported results allow formulating an important hypothesis that the laser-produced plasma modifies strongly the laser intensity distribution. It is shown how such a modification depends on the relative position and distance of the focal point to the target surface. Of particular importance is whether the focal point is located inside or in front of the target. The irradiation geometry is crucial for the possibility of generating plasma jets by laser radiation. Well-formed jet-like plasma structures can be created if an initially homogeneous laser intensity distribution is transformed in the plasma to an annular one

  13. Spectroscopic analysis of coal plasma emission produced by laser ablation

    OpenAIRE

    Vera-Londoño, Liliana Patricia; Pérez-Taborda, Jaime Andrés; Riascos-Landázuri, Henry

    2016-01-01

    An analysis of plasma produced by laser ablation using 1,064 nm of laser radiation from a Q-switched Nd:YAG on coal mineral samples under air ambient, was performed. The emission of molecular band systems such as C2 Swan System , the First Negative System N2 (Band head at 501.53 nm) and different emission lines were investigated using the optical emission spectroscopy technique. The C2 molecular spectra (Swan band) were analyzed to determine vibrational temperature (0.62 eV). The density and ...

  14. Electron-Beam Produced Air Plasma: Optical and Electrical Diagnostics

    Science.gov (United States)

    Vidmar, Robert; Stalder, Kenneth; Seeley, Megan

    2006-10-01

    High energy electron impact excitation is used to stimulate optical emissions that quantify the measurement of electron beam current. A 100 keV 10-ma electron beam source is used to produce air plasma in a test cell at a pressure between 1 mTorr and 760 Torr. Optical emissions originating from the N2 2^nd positive line at 337.1 nm and the N2^+ 1^st negative line at 391.4 nm are observed. Details on calibration using signals from an isolated transmission window and a Faraday plate are discussed. Results using this technique and other electrical signal are presented.

  15. Saturation of Langmuir waves in laser-produced plasmas

    International Nuclear Information System (INIS)

    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

  16. Porous materials produced from incineration ash using thermal plasma technology.

    Science.gov (United States)

    Yang, Sheng-Fu; Chiu, Wen-Tung; Wang, To-Mai; Chen, Ching-Ting; Tzeng, Chin-Ching

    2014-06-01

    This study presents a novel thermal plasma melting technique for neutralizing and recycling municipal solid waste incinerator (MSWI) ash residues. MSWI ash residues were converted into water-quenched vitrified slag using plasma vitrification, which is environmentally benign. Slag is adopted as a raw material in producing porous materials for architectural and decorative applications, eliminating the problem of its disposal. Porous materials are produced using water-quenched vitrified slag with Portland cement and foaming agent. The true density, bulk density, porosity and water absorption ratio of the foamed specimens are studied here by varying the size of the slag particles, the water-to-solid ratio, and the ratio of the weights of the core materials, including the water-quenched vitrified slag and cement. The thermal conductivity and flexural strength of porous panels are also determined. The experimental results show the bulk density and the porosity of the porous materials are 0.9-1.2 g cm(-3) and 50-60%, respectively, and the pore structure has a closed form. The thermal conductivity of the porous material is 0.1946 W m(-1) K(-1). Therefore, the slag composite materials are lightweight and thermal insulators having considerable potential for building applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. 201Hg excitation in plasma produced by laser

    International Nuclear Information System (INIS)

    Comet, Maxime

    2014-01-01

    The use of high power lasers allows the study of the properties of matter in extreme conditions of temperature and density. Indeed, the interaction of a power laser and a target creates a plasma in which the temperature is high enough to reach important degrees of ionization. These conditions can allow the excitation of the nucleus. A nucleus of interest to study the processes of nuclear excitation is the 201 Hg. This work aims to design an experiment where the 201 Hg excitation will be observed in a plasma produced by a high power laser. The first part of this manuscript presents the calculation of the expected nuclear excitation rates in the plasma. For about ten years, nuclear excitation rates have been calculated using the average atom model. To validate this model a code named ADAM (French acronym for Beyond The Average Atom Model) was developed to calculate the nuclear excitation rates under the DCA (Detailed Configuration Accounting) hypothesis. ADAM allows us to deduce the thermo dynamical domain where the nuclear excitation rates determined with the average atom model are relevant. The second part of this manuscript presents the coupling of the excitation rate calculation with a hydrodynamic code to calculate the number of excited nuclei produced in one laser shot for different laser intensity. Finally, in the last part, first experimental approaches which will be used to design an experiment on a laser installation are presented. These approaches are based on the detection and determination of the amount of multicharged ions obtained far from the target (∼80 cm). For this purpose, an electrostatic analyzer was used. (author) [fr

  18. Analysis of extreme ultraviolet spectra from laser produced rhenium plasmas

    International Nuclear Information System (INIS)

    Wu, Tao; Dunne, Padraig; O’Reilly, Fergal; Sokell, Emma; Liu, Luning; O’Sullivan, Gerry; Higashiguchi, Takeshi; Suzuki, Yuhei; Arai, Goki; Dinh, Thanh-Hung; Li, Bowen

    2015-01-01

    Extreme ultraviolet spectra of highly-charged rhenium ions were observed in the 1–7 nm region using two Nd:YAG lasers with pulse lengths of 150 ps and 10 ns, respectively, operating at a number of laser power densities. The maximum focused peak power density was 2.6 × 10 14 W cm −2 for the former and 5.5 × 10 12 W cm −2 for the latter. The Cowan suite of atomic structure codes and unresolved transition array (UTA) approach were used to calculate and interpret the emission properties of the different spectra obtained. The results show that n = 4-n = 4 and n = 4-n = 5 UTAs lead to two intense quasi-continuous emission bands in the 4.3–6.3 nm and 1.5–4.3 nm spectral regions. As a result of the different ion stage distributions in the plasmas induced by ps and ns laser irradiation the 1.5–4.3 nm UTA peak moves to shorter wavelength in the ps laser produced plasma spectra. For the ns spectrum, the most populated ion stage during the lifetime of this plasma that could be identified from the n = 4-n = 5 transitions was Re 23+ while for the ps plasma the presence of significantly higher stages was demonstrated. For the n = 4-n = 4 4p 6 4d N -4p 5 4d N+1  + 4p 6 4d N−1 4f transitions, the 4d-4f transitions contribute mainly in the most intense 4.7–5.5 nm region while the 4p-4d subgroup gives rise to a weaker feature in the 4.3–4.7 nm region. A number of previously unidentified spectral features produced by n = 4-n = 5 transitions in the spectra of Re XVI to Re XXXIX are identified. (paper)

  19. Instabilities in superconductors and in intense laser produced plasma's

    International Nuclear Information System (INIS)

    Banerjee, Satyajit S.; Mohan, Shyam; Sinha, Jaivardhan; Kahaly, Subendhu; Ravindra Kumar, G.

    2007-01-01

    In this talk I will attempt to discuss phenomena's in two areas of physics which appear quite divorced from each other, viz., superconductivity and plasma's. The first portion of the talk will describe the behavior of a collection of vortices in superconductors in a random pinning environment. Vortices manifest themselves in a variety of systems, like in fluids and in type II superconductors. A collection of vortices inside superconductors behaves like an elastic media. Investigating this elastic medium of the vortex state is a convenient prototype for investigating similar physics in a wide variety of systems, viz., charge density waves, Wigner crystals, magnetic domains, etc. The behavior of all these systems can be generalized under, nature of elastic media in the presence of a random pinning environment and thermal fluctuations. Based on the idea that softer matter is easy to pin we have attempted to investigate how the vortex lattice disorders as its gets softer. Surprisingly we find evidence to two distinct types of instabilities in the vortex lattice instead of one. These two instabilities produce vastly different effects on certain quantities associated with the extent of disorder in the superconductor. It appears that prior to softening of the vortex state, a heterogeneously pinned state of the vortex matter appears, perhaps through a KT like transition. In the second part of the talk, I will attempt to describe some of our recent results pertaining to instabilities and the appearance of giant magnetic fields in plasma's. These results have been obtained with a high sensitivity magneto-optical imaging setup we have developed at IIT Kanpur. Using the setup, we investigate distribution of magnetic fields around dense solid plasmas generated by intense p-polarized laser (∼10 16 Wcm -2 , 100 fs) irradiation of magnetic tapes, using high sensitivity magneto optical imaging technique. We demonstrate giant axial magnetic fields and map out for the first time

  20. Modelling vacuum arcs : from plasma initiation to surface interactions

    International Nuclear Information System (INIS)

    Timko, H.

    2011-01-01

    A better understanding of vacuum arcs is desirable in many of today's 'big science' projects including linear colliders, fusion devices, and satellite systems. For the Compact Linear Collider (CLIC) design, radio-frequency (RF) breakdowns occurring in accelerating cavities influence efficiency optimisation and cost reduction issues. Studying vacuum arcs both theoretically as well as experimentally under well-defined and reproducible direct-current (DC) conditions is the first step towards exploring RF breakdowns. In this thesis, we have studied Cu DC vacuum arcs with a combination of experiments, a particle-in-cell (PIC) model of the arc plasma, and molecular dynamics (MD) simulations of the subsequent surface damaging mechanism. We have also developed the 2D Arc-PIC code and the physics model incorporated in it, especially for the purpose of modelling the plasma initiation in vacuum arcs. Assuming the presence of a field emitter at the cathode initially, we have identified the conditions for plasma formation and have studied the transitions from field emission stage to a fully developed arc. The 'footing' of the plasma is the cathode spot that supplies the arc continuously with particles; the high-density core of the plasma is located above this cathode spot. Our results have shown that once an arc plasma is initiated, and as long as energy is available, the arc is self-maintaining due to the plasma sheath that ensures enhanced field emission and sputtering.The plasma model can already give an estimate on how the time-to-breakdown changes with the neutral evaporation rate, which is yet to be determined by atomistic simulations. Due to the non-linearity of the problem, we have also performed a code-to-code comparison. The reproducibility of plasma behaviour and time-to-breakdown with independent codes increased confidence in the results presented here. Our MD simulations identified high-flux, high-energy ion bombardment as a possible mechanism forming the early

  1. Sn ion energy distributions of ns- and ps-laser produced plasmas

    Science.gov (United States)

    Bayerle, A.; Deuzeman, M. J.; van der Heijden, S.; Kurilovich, D.; de Faria Pinto, T.; Stodolna, A.; Witte, S.; Eikema, K. S. E.; Ubachs, W.; Hoekstra, R.; Versolato, O. O.

    2018-04-01

    Ion energy distributions arising from laser-produced plasmas of Sn are measured over a wide laser parameter space. Planar-solid and liquid-droplet targets are exposed to infrared laser pulses with energy densities between 1 J cm‑2 and 4 kJ cm‑2 and durations spanning 0.5 ps to 6 ns. The measured ion energy distributions are compared to two self-similar solutions of a hydrodynamic approach assuming isothermal expansion of the plasma plume into vacuum. For planar and droplet targets exposed to ps-long pulses, we find good agreement between the experimental results and the self-similar solution of a semi-infinite simple planar plasma configuration with an exponential density profile. The ion energy distributions resulting from solid Sn exposed to ns-pulses agrees with solutions of a limited-mass model that assumes a Gaussian-shaped initial density profile.

  2. An investigation of the structure of plasma produced by reflected shock waves

    International Nuclear Information System (INIS)

    Phillips, M.G.R.; Pugatschew, A.A.

    1979-05-01

    Space and time resolved measurements of electron density and temperature have been made in the reflected-shock plasma produced by a Mach 20 incident shock wave propagating in argon at an initial pressure of 1.5 Torr. The peak electron density was found to decrease away from the reflecting wall in such a way that the plasma was fairly uniform at all times. Close to the reflecting wall (0.2 cm away) the measured peak electron density was close to (i.e. about 20% lower than) the predicted equilibrium value but further away (1.0 cm) it was lower by a factor 4. Possible reasons for this discrepancy are discussed. Calculations of reflected-shock plasma structure based on incident shock structure are only partially supported by available experimental evidence

  3. X-ray spectroscopic diagnostics of plasma produced by femtosecond laser pulses at interaction with cluster target

    International Nuclear Information System (INIS)

    Skobelev, I.Yu.; Faenov, A.Ya.; Magunov, A.I.

    2002-01-01

    By means of X-ray spectroscopy one determined parameters of plasma produced at interaction of supershort laser pulses with cluster targets. One investigated into the effect of both initial properties of a cluster target and properties of a laser pulse on plasma characteristics. To diagnose plasma one applied a model of production of emitting spectra covering a whole number of free parameters. The conducted experimental investigations show that the investigated model of cluster heating by supershort pulses is the actual physical model, while the applied fitting parameters have a meaning of average values of plasma parameters [ru

  4. The role of current sheet formation in driven plasmoid reconnection in laser-produced plasma bubbles

    Science.gov (United States)

    Lezhnin, Kirill; Fox, William; Bhattacharjee, Amitava

    2017-10-01

    We conduct a multiparametric study of driven magnetic reconnection relevant to recent experiments on colliding magnetized laser produced plasmas using the PIC code PSC. Varying the background plasma density, plasma resistivity, and plasma bubble geometry, the results demonstrate a variety of reconnection behavior and show the coupling between magnetic reconnection and global fluid evolution of the system. We consider both collision of two radially expanding bubbles where reconnection is driven through an X-point, and collision of two parallel fields where reconnection must be initiated by the tearing instability. Under various conditions, we observe transitions between fast, collisionless reconnection to a Sweet-Parker-like slow reconnection to complete stalling of the reconnection. By varying plasma resistivity, we observe the transition between fast and slow reconnection at Lundquist number S 103 . The transition from plasmoid reconnection to a single X-point reconnection also happens around S 103 . We find that the criterion δ /di < 1 is necessary for fast reconnection onset. Finally, at sufficiently high background density, magnetic reconnection can be suppressed, leading to bouncing motion of the magnetized plasma bubbles.

  5. High beta capture and mirror confinement of laser produced plasmas. Semiannual report, July 1, 1975--January 31, 1976

    International Nuclear Information System (INIS)

    Haught, A.F.; Polk, D.H.; Fader, W.J.; Tomlinson, R.G.; Jong, R.A.; Ard, W.B.; Mensing, A.E.; Churchill, T.L.; Stufflebeam, J.H.; Bresnock, F.J.

    1976-01-01

    The Laser Initiated Target Experiment (LITE) at the United Technologies Research Center is designed to address the target plasma buildup approach to a steady state mirror fusion device. A dense, mirror confined, target plasma is produced by high power laser irradiation of a solid lithium hydride particle, electrically suspended in a vacuum at the center of an established minimum-B magnetic field. Following expansion in and capture by the magnetic field, this target plasma is irradiated by an energetic neutral hydrogen beam. Charge exchange collisions with energetic beam particles serve to heat the confined plasma while ionization of the neutral beam atoms and trapping in the mirror magnetic field add particles to the confined plasma. For sufficiently high beam intensities, confined plasmas losses will be offset so that buildup of the plasma density occurs, thus demonstrating sustenance and fueling as well as the heating by neutral beam injection of a steady state mirror fusion device. Investigations of the decay of the magnetically confined target plasmas and initial studies of energetic neutral beam injection into confined target plasmas, conducted during this report period, are presented. Additional development of the LITE experimental systems including improvements in the laser plasma production facility, the energetic neutral beam line, and the heavy ion probe diagnostic is reported. A series of calculations on enhanced scattering and classical decay for plasma mirror confined in a LITE type system are discussed

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

    Czech Academy of Sciences Publication Activity Database

    Kasperczuk, A.; Pisarczyk, T.; Badziak, J.; Borodziuk, S.; Chodukowski, T.; Gus’kov, S.Yu.; Demchenko, N. N.; Ullschmied, Jiří; Krouský, Eduard; Mašek, Karel; Pfeifer, Miroslav; Rohlena, Karel; Skála, Jiří; Pisarczyk, P.

    2010-01-01

    Roč. 17, č. 11 (2010), s. 114505 ISSN 1070-664X R&D Projects: GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z10100523 Keywords : Composed laser targets * target material * laser produced-plasma jets * PALS laser Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.320, year: 2010 http://pop.aip.org/ resource /1/phpaen/v17/i11/p114505_s1

  7. Filter media properties of mineral fibres produced by plasma spray.

    Science.gov (United States)

    Prasauskas, Tadas; Matulevicius, Jonas; Kliucininkas, Linas; Krugly, Edvinas; Valincius, Vitas; Martuzevicius, Dainius

    2016-01-01

    The purpose of this study was to determine the properties of fibrous gas filtration media produced from mineral zeolite. Fibres were generated by direct current plasma spray. The paper characterizes morphology, chemical composition, geometrical structure of elementary fibres, and thermal resistance, as well as the filtration properties of fibre media. The diameter of the produced elementary fibres ranged from 0.17 to 0.90 μm and the length ranged from 0.025 to 5.1 mm. The release of fibres from the media in the air stream was noticed, but it was minimized by hot-pressing the formed fibre mats. The fibres kept their properties up to the temperature of 956°C, while further increase in temperature resulted in the filter media becoming shrunk and brittle. The filtration efficiency of the prepared filter mats ranged from 95.34% to 99.99% for aerosol particles ranging in a size between 0.03 and 10.0 μm. Unprocessed fibre media showed the highest filtration efficiency when filtering aerosol particles smaller than 0.1 µm. Hot-pressed filters were characterized by the highest quality factor values, ranging from 0.021 to 0.064 Pa(-1) (average value 0.034 Pa(-1)).

  8. PlasmaPy: initial development of a Python package for plasma physics

    Science.gov (United States)

    Murphy, Nicholas; Leonard, Andrew J.; Stańczak, Dominik; Haggerty, Colby C.; Parashar, Tulasi N.; Huang, Yu-Min; PlasmaPy Community

    2017-10-01

    We report on initial development of PlasmaPy: an open source community-driven Python package for plasma physics. PlasmaPy seeks to provide core functionality that is needed for the formation of a fully open source Python ecosystem for plasma physics. PlasmaPy prioritizes code readability, consistency, and maintainability while using best practices for scientific computing such as version control, continuous integration testing, embedding documentation in code, and code review. We discuss our current and planned capabilities, including features presently under development. The development roadmap includes features such as fluid and particle simulation capabilities, a Grad-Shafranov solver, a dispersion relation solver, atomic data retrieval methods, and tools to analyze simulations and experiments. We describe several ways to contribute to PlasmaPy. PlasmaPy has a code of conduct and is being developed under a BSD license, with a version 0.1 release planned for 2018. The success of PlasmaPy depends on active community involvement, so anyone interested in contributing to this project should contact the authors. This work was partially supported by the U.S. Department of Energy.

  9. Lazer-produced plasma in a strong magnetic field

    International Nuclear Information System (INIS)

    Kaitmazov, S.D.; Shklovskij, E.I.

    1978-01-01

    Investigations on interaction of laser plasma with the magnetic field in the range of 100-300 kOe are surveyed. Problems associated with the effect of the field on the optical breakdown threshold in gases, the geometry (kinetics) of laser plasma and its radiation are mainly considered. It is noted that the magnetic field may reduce the o tical breakdown threshold in gases, promote the spreading of plasma predominantly in the direction of tice magnetic field, and also affect (increase in the visible range) the radiation intensity of the laser plasma. The effect of the magnetic field on the temperature of the laser plasma is not completely understood yet, but the very fact of existence of this dependence is important; it enables one to search for conditions under which the magnetic field would promote the increase at the temperature of laser plasma

  10. Ion collisions and deceleration in laser-produced plasma-jet interaction with walls

    Czech Academy of Sciences Publication Activity Database

    Renner, Oldřich; Krouský, Eduard; Liska, R.; Šmíd, M.; Larroche, O.; Dalimier, E.

    2011-01-01

    Roč. 56, - (2011), T165-T174 ISSN 0001-7043 R&D Projects: GA MŠk(CZ) LC528; GA ČR GAP205/10/0814 Institutional research plan: CEZ:AV0Z10100523 Keywords : laser-produced plasma jets * plasma-wall interaction * plasma diagnostics * X-ray spectroscopy * fluid and kinetic plasma simulation Subject RIV: BL - Plasma and Gas Discharge Physics

  11. Initial evolution of nonlinear magnetic islands in high temperature plasmas

    International Nuclear Information System (INIS)

    Kotschenreuther, M.

    1988-06-01

    The evolution of nonlinear magnetic islands is computed in the kinetic collisionality regime called the semicollisional regime, which is appropriate to present fusion confinement devices. Realistic effects are included, such as the presence of small external field errors, radial electric fields, and omega. When present simultaneously, these effects can greatly change the stability of small amplitude nonlinear islands. Islands with Δ' > O can sometimes be prevented from growing to macroscopic size; it is also possible to produce moderate mode-number nonlinear instabilities in the plasma edge. Furthermore, island growth can be prevented by application of external fields with suitably chosen amplitude and frequency

  12. Direct currents produced by hf heating of plasma

    International Nuclear Information System (INIS)

    Klima, R.

    1974-01-01

    In addition to the well-known diffusion currents, toroidal direct currents arise in h.f. heated plasmas as a result of a momentum transfer from the h.f. field to plasma particles. The estimates of steady-state conditions are given for these currents. Particularly, the possibility of stationary operation of a Tokamak device is analyzed. (author)

  13. Initial biocompatibility of plasma polymerized hexamethyldisiloxane films with different wettability

    Science.gov (United States)

    Krasteva, N. A.; Toromanov, G.; Hristova, K. T.; Radeva, E. I.; Pecheva, E. V.; Dimitrova, R. P.; Altankov, G. P.; Pramatarova, L. D.

    2010-11-01

    Understanding the relationships between material surface properties, behaviour of adsorbed proteins and cellular responses is essential to design optimal material surfaces for tissue engineering. In this study we modify thin layers of plasma polymerized hexamethyldisiloxane (PPHMDS) by ammonia treatment in order to increase surface wettability and the corresponding biological response. The physico-chemical properties of the polymer films were characterized by contact angle (CA) measurements and Fourier Transform Infrared Spectroscopy (FTIR) analysis.Human umbilical vein endothelial cells (HUVEC) were used as model system for the initial biocompatibility studies following their behavior upon preadsorption of polymer films with three adhesive proteins: fibronectin (FN), fibrinogen (FG) and vitronectin (VN). Adhesive interaction of HUVEC was evaluated after 2 hours by analyzing the overall cell morphology, and the organization of focal adhesion contacts and actin cytoskeleton. We have found similar good cellular response on FN and FG coated polymer films, with better pronounced vinculin expression on FN samples while. Conversely, on VN coated surfaces the wettability influenced significantly initial celular interaction spreading. The results obtained suggested that ammonia plasma treatment can modulate the biological activity of the adsorbed protein s on PPHMDS surfaces and thus to influence the interaction with endothelial cells.

  14. Study of multicharged ions in the laser-produced plasmas

    International Nuclear Information System (INIS)

    Jaegle, P.; Carillon, A.; Jamelot, G.; Wehenkel, C.; Sureau, A.; Guennou, H.

    1980-01-01

    With respect to hot plasmas, laser induced plasmas have an especially high density, with a steep partial gradient and a fast temporal variation of temperature and density. The study of multicharged ion radiation, wich is necessary to perform diagnostics of plasma parameters, opens a new field for atomic physics investigations, including identification of peculiar lines, which are not observed in other conditions, large changes in line profiles due to radiative transfer and to both shift and broadening by Stark effect. Departure from population equilibrium takes place in these plasmas, going possibly so far as population inversion between ionic levels in an energy range covering EUV and soft X-rays. Experimental and theoretical study of these phenomena are in progress and needs to find solutions for complicated problems. Here, recent works performed with the laser of the GRECO 'Interaction Laser-Matiere' are briefly presented [fr

  15. Investigation of plasma stream collision produced by thin films irradiated by powerful pulsed electron beam

    International Nuclear Information System (INIS)

    Efremov, V P; Demidov, B A; Ivkin, M V; Mescheryakov, A N; Petrov, V A; Potapenko, A I

    2006-01-01

    Collision of fast plasma streams in vacuum is investigated. Plasma streams were produced by irradiation of thin foils with a powerful pulsed electron beam. Interaction of the plasma flows was studied by using frame and streak cameras. One-dimensional numerical simulation was carried out. Application of this method for porous ICF targets and high-energy physics is discussed

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

    International Nuclear Information System (INIS)

    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.

    2001-01-01

    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'') ∼ 0.1-1 may be suppressed in these plasmas, while modes with k(subscript ''theta'') rho(subscript ''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 [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

  17. Ion turbulence and thermal transport in laser-produced plasmas

    International Nuclear Information System (INIS)

    Barr, H.C.; Boyd, T.J.M.

    1982-01-01

    In the interaction of high-intensity lasers with target plasmas the transport of thermal energy from the region in which the radiation is absorbed, to the cold dense plasma in the interior of the target, is an issue of central importance. The role of ion turbulence as a flux limiter is addressed with particular regard to recent experiments in which target plasmas were irradiated by 1.06 μm neodymium laser light at irradiances of 10 15 W cm - 2 and greater. Saturation levels of the ion-acoustic turbulence driven by a combination of a suprathermal electron current and a heat flux are calculated on the basis of perturbed orbit theory. The levels of turbulence are found to be markedly lower than those commonly estimated from simple trapping arguments and too low to explain the thermal flux inhibition observed in the experiments used as a basis for the model. (author)

  18. Study of the state of the plasma produced by oblique-incident laser

    International Nuclear Information System (INIS)

    Sheng Jiatian; Zhang Guoping; Liu Wei; Ye Chunfu; Hu Shengyong

    1997-01-01

    The plasma state and the gain region produced by the oblique-incidence laser on Ge target are studied and are compared with that produced by the vertical one. As a result of study, the absorption efficiency of the pumping energy turns far smaller, the plasma state changes remarkable and the gain region becomes much narrower when incident angle is greater than 30 degree

  19. Nanosecond framing photography for laser-produced interstreaming plasmas

    International Nuclear Information System (INIS)

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

    1988-01-01

    Using a fast-gated (120 psec-5 nsec) microchannel-plate optical camera (gated optical imager), framing photographs have been taken of the rapidly streaming laser plasma (∼ 5 x 10 7 cm/sec) passing through a vacuum or a background gas, with and without a magnetic field. Observations of Large-Larmor-Radius Interchange Instabilities are presented

  20. Characterisation of plasmas produced by the "torche à injection axiale"

    NARCIS (Netherlands)

    Jonkers, J.; Selen, L.J.M.; Mullen, van der J.J.A.M.; Timmermans, E.A.H.; Schram, D.C.; Fauchais, P.

    1997-01-01

    Two different kinds of plasmas created by the microwave driven Torche a' Injection Axiale (TIA) are investigated: one with helium and the other with argon as the main gas. By using abs. line intensity measurements, the densities of the excited states are detd. Applying the ideal gas law gives the

  1. Characterisation of plasmas produced by the "Torche a Injection Axiale"

    NARCIS (Netherlands)

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

    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

  2. Characterisation of plasmas produced by the "Torche a Injection Axciale"

    NARCIS (Netherlands)

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

    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

  3. Characteristics of the aluminum alloy plasma produced by a 1064 ...

    Indian Academy of Sciences (India)

    using the Boltzmann plot method with nine strong neutral aluminum lines. Due to the ... solids. At the same time, LIBS is considered a non-destructive technique because ... On the one hand, studying the spatial distribution of metal plasma ... sition probability ratios are in excellent agreement with the NIST database within.

  4. Soft x-ray source by laser produced Xe plasma

    International Nuclear Information System (INIS)

    Amano, Sho; Masuda, Kazuya; Miyamoto, Shuji; Mochizuki, Takayasu

    2010-01-01

    The laser plasma soft X-ray source in the wavelength rage of 5-17 nm was developed, which consisted of the rotating drum system supplying cryogenic Xe target and the high repetition rate pulse Nd:YAG slab laser. We found the maximum conversion efficiency of 30% and it demonstrated the soft X-ray generation with the high repetition rate pulse of 320 pps and the high average power of 20 W. The soft X-ray cylindrical mirror was developed and successfully focused the soft X-ray with an energy intensity of 1.3 mJ/cm 2 . We also succeeded in the plasma debris mitigation with Ar gas. This will allow a long lifetime of the mirror and a focusing power intensity of 400 mW/cm 2 with 320 pps. The high power soft X-ray is useful for various applications. (author)

  5. Spectral modeling of laser-produced underdense titanium plasmas

    Science.gov (United States)

    Chung, Hyun-Kyung; Back, Christina A.; Scott, Howard A.; Constantin, Carmen; Lee, Richard W.

    2004-11-01

    Experiments were performed at the NIKE laser to create underdense low-Z plasmas with a small amount of high-Z dopant in order to study non-LTE population kinetics. An absolutely calibrated spectra in 470-3000 eV was measured in time-resolved and time-averaged fashion from SiO2 aerogel target with 3% Ti dopant. K-shell Ti emission was observed as well as L-shell Ti emission. Time-resolved emission show that lower energy photons peak later than higher energy photons due to plasma cooling. In this work, we compare the measured spectra with non-LTE spectral calculations of titanium emission at relatively low temperatures distributions dominated by L-shell ions will be discussed.

  6. Density oscillations in laser produced plasma decelerated by ...

    Indian Academy of Sciences (India)

    during deceleration under the effect of external magnetic field. This has been verified with the help of figure 3, which shows the variation of x-ray intensity emitted from the plasma with laser intensity at 0.01 and 0.6 T magnetic field. Enhancement in the x-ray emission by 2–3 times in the presence of magnetic field has already ...

  7. Increase of hot initial plasma energy content in the end system of AMBAL-M during hydrogen puffing

    International Nuclear Information System (INIS)

    Akhmetov, Timour; Bekher, Sergei; Davydenko, Vladimir; Krivenko, Aleksander; Muraviev, Maksim; Reva, Vladimir; Sokolov, Vladimir

    2001-01-01

    At the end system of the completely axisymmetric mirror trap AMBAL-M the experiments on creation and study of a hot initial plasma have been performed. In the experiments a gas-box was used for hydrogen supply into the hot startup plasma in the mirror trap to increase the plasma density. The hot initial plasma in the trap was produced by the trapping of a plasma stream with developed electrostatic turbulence generated by a gas-discharge source located outside the entrance throat. It was found that in addition to the increase in the plasma density by a factor of 2-3, hydrogen puffing resulted in an unexpected nearly twofold diamagnetism increase. The gas puffing did not reduce the electron temperature in the trap. Essential for explanation of the observed effect is the fact that with the gas puffing the measured plasma potential in the trap increased. The increase in the plasma potential enhanced the trapping of the ion flow entering the trap and increased the average energy of the electron flow entering the trap. It was found that with the increasing hydrogen puffing rate plasma parameters in the trap were saturated. (author)

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

    International Nuclear Information System (INIS)

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

    2010-01-01

    Using an ultrafast electron probe capable of four-dimensional diagnosis, the initial stage of fast evolving plasmas produced by a 10 14 W/cm 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 7 suprathermal electrons with the outermost layer expanding at an average speed of 1.2x10 7 m/s.

  9. Proton radiography of magnetic field in laser produced plasma

    International Nuclear Information System (INIS)

    Le Pape, S.; Patel, P.; Chen, S.; Town, R.; Mackinnon, A.

    2009-01-01

    Electromagnetic fields generated by the interaction with plasmas of long-pulse laser beams relevant to inertial confinement fusion have been measure. A proton beam generated by the interaction of an ultra intense laser with a thin metallic foil is used to probe the B-fields. The proton beam then generated is temporally short (of the order of a ps), highly laminar and hence equivalent to a virtual point which makes it an ideal source for radiography. We have investigated, using face-on radiography, B fields at intensity around 10 14 W/cm 2 due to the non co-linearity of temperature and density gradients. (authors)

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

    Science.gov (United States)

    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

  11. Experiments on hot and dense laser-produced plasmas

    International Nuclear Information System (INIS)

    Back, C.A.; Woolsey, N.C.; Asfaw, A.; Glenzer, S.H.; Hammel, B.A.; Keane, C.J.; Lee, R.W.; Liedahl, D.; Moreno, J.C.; Nash, J.K.; Osterheld, A.L.; Calisti, A.; Stamm, R.; Talin, B.; Godbert, L.; Mosse, C.; Ferri, S.; Klein, L.

    1996-01-01

    Plasmas generated by irradiating targets with ∼20 kJ of laser energy are routinely created in inertial confinement fusion research. X-ray spectroscopy provides one of the few methods for diagnosing the electron temperature and electron density. For example, electron densities approaching 10 24 cm -3 have been diagnosed by spectral linewidths. However, the accuracy of the spectroscopic diagnostics depends on the population kinetics, the radiative transfer, and the line shape calculations. Analysis for the complex line transitions has recently been improved and accelerated by the use of a database where detailed calculations can be accessed rapidly and interactively. Examples of data from Xe and Ar doped targets demonstrate the current analytic methods. First we will illustrate complications that arise from the presence of a multitude of underlying spectral lines. Then, we will consider the Ar He-like 1s 2 ( 1 S 0 ) - 1s3p( 1 P 0 ) transition where ion dynamic effects may affect the profile. Here, the plasma conditions are such that the static ion microfield approximation is no longer valid; therefore in addition to the width, the details of the line shape can be used to provide additional information. We will compare the data to simulations and discuss the possible pitfalls involved in demonstrating the effect of ion dynamics on lineshapes

  12. Characterization of plasma nitrided layers produced on sintered iron

    Directory of Open Access Journals (Sweden)

    Marcos Alves Fontes

    2014-07-01

    Full Text Available Plasma nitriding is a thermo-physical-chemical treatment process, which promotes surface hardening, caused by interstitial diffusion of atomic nitrogen into metallic alloys. In this work, this process was employed in the surface modification of a sintered ferrous alloy. Scanning electron microscopy (SEM, X-ray diffraction (XRD analyses, and wear and microhardness tests were performed on the samples submitted to ferrox treatment and plasma nitriding carried out under different conditions of time and temperature. The results showed that the nitride layer thickness is higher for all nitrided samples than for ferrox treated samples, and this layer thickness increases with nitriding time and temperature, and temperature is a more significant variable. The XRD analysis showed that the nitrided layer, for all samples, near the surface consists in a mixture of γ′-Fe4N and ɛ-Fe3N phases. Both wear resistance and microhardness increase with nitriding time and temperature, and temperature influences both the characteristics the most.

  13. Ponderomotive force, magnetic fields and hydrodynamics of laser produced plasmas

    International Nuclear Information System (INIS)

    Bobin, J.-L.; Wee Woo; Degroot, J.-S.

    1977-01-01

    Nonlinear effects deeply change the structure of a laser driven plasma flow. For high intensities, the radiation pressure should be taken into account. It acts through a ponderomotive force proportional to the electron density and to the gradient of the mean electric field energy density of the incident wave. Static magnetic fields originate from a term in the ponderomotive force which includes radiation absorption and whose curl is non zero. The basic properties of the structure are determined analytically in the absence of thermal conductivity and magnetic fields: steep density gradient close to the cut-off density, shelf at lower densities. The conditions of a steady state regime are set up. The isothermal case is specially investigated. It is shown that the cavities which are created in a motionless plasma may disappear due to the onset of a flow. Regions in which electromagnetic forces arising from the static field compensate the ponderomotive force are determined. The subsequent effects on the flow itself are studied [fr

  14. Simultaneous streak and frame interferometry for electron density measurements of laser produced plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Quevedo, H. J., E-mail: hjquevedo@utexas.edu; McCormick, M.; Wisher, M.; Bengtson, Roger D.; Ditmire, T. [Center for High Energy Density Science, Department of Physics, University of Texas at Austin, Austin, Texas 78712 (United States)

    2016-01-15

    A system of two collinear probe beams with different wavelengths and pulse durations was used to capture simultaneously snapshot interferograms and streaked interferograms of laser produced plasmas. The snapshots measured the two dimensional, path-integrated, electron density on a charge-coupled device while the radial temporal evolution of a one dimensional plasma slice was recorded by a streak camera. This dual-probe combination allowed us to select plasmas that were uniform and axisymmetric along the laser direction suitable for retrieving the continuous evolution of the radial electron density of homogeneous plasmas. Demonstration of this double probe system was done by measuring rapidly evolving plasmas on time scales less than 1 ns produced by the interaction of femtosecond, high intensity, laser pulses with argon gas clusters. Experiments aimed at studying homogeneous plasmas from high intensity laser-gas or laser-cluster interaction could benefit from the use of this probing scheme.

  15. Laser radiation forces in laser-produced plasmas

    International Nuclear Information System (INIS)

    Stamper, J.A.

    1975-01-01

    There are two contributions to laser radiation forces acting on the electrons. Transfer of momentum from the fields to the electrons results in a field pressure contribution and occurs whenever there is absorption or reflection. The quiver pressure contribution, associated with electron quiver motion, is due to inhomogeneous fields inducing momentum transfer within the electron system. It is shown that the ponderomotive force with force density, (epsilon-1)/8πdel 2 >, does not include the field contribution and does not lead to a general description of macroscopic processes. A theory is discussed which does give a general macroscopic description (absorption, reflection, refraction, and magnetic field generation) and which reduces to the ponderomotive force for purely sinusoidal fields in a neutral, homogeneous, nonabsorbing plasma

  16. Morphology of magnetic fields generated in laser-produced plasmas

    International Nuclear Information System (INIS)

    Boyd, T.J.M.; Cooke, D.

    1988-01-01

    Magnetic fields in the megagauss range have been measured in experiments on plasmas generated by irradiating targets with high power lasers. A study of the morphology of these self-generated fields is important not only for its intrinsic interest but for possible implications in laser--target physics. In this paper work on the numerical modeling of large magnetic fields generated in target experiments is reported. The results show generally satisfactory agreement with the fields measured experimentally both in terms of the magnitude of the peak fields and their morphology. In the numerical model the contribution from the Hall term in describing the evolution of the magnetic field is shown to be important especially in short pulse (≅100 psec) experiments

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

    Czech Academy of Sciences Publication Activity Database

    Kasperczuk, A.; Pisarczyk, T.; Chodukowski, T.; Kalinowska, Z.; Parys, P.; Renner, Oldřich; Gus´kov, S.Y.; Demchenko, N. N.; Ullschmied, Jiří; Krouský, Eduard; Pfeifer, Miroslav; Rohlena, Karel; Skála, Jiří

    2012-01-01

    Roč. 19, č. 9 (2012), s. 1-8 ISSN 1070-664X R&D Projects: GA MŠk(CZ) 7E09092; GA MŠk(CZ) LC528; GA ČR GAP205/10/0814 Grant - others:7FP LASERLAB-EUROPE(XE) 228334 Program:FP7 Institutional research plan: CEZ:AV0Z10100523; CEZ:AV0Z20430508 Keywords : laser-mater interaction * plasma jets production * x-ray spectroscopy * particle plasma diagnosis * ion charge density * plasma temperature Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.376, year: 2012

  18. Calculation of high-pressure argon plasma parameters produced by excimer laser

    International Nuclear Information System (INIS)

    Tsuda, Norio; Yamada, Jun

    2000-01-01

    When a XeCl excimer laser light was focused in a high-pressure argon gas up to 150 atm, a dense plasma developed not only backward but also forward. It is important to study on the electron density and temperature of the laser-induced plasma in the high-pressure gas. The electron density and temperature in high-pressure argon plasma produced by XeCl excimer laser has been calculated and compared with the experimental data. (author)

  19. Transition probabilities of some Si II lines obtained by laser produced plasma emission

    International Nuclear Information System (INIS)

    Blanco, F.; Botho, B.; Campos, J.

    1995-01-01

    The absolute transition probabilities for 28 Si II spectral lines have been determined by measurement of emission line intensities from laser-produced plasmas of Si in Ar and Kr atmospheres. The studied plasma has a temperature of about 2 . 10 4 K and 10 17 cm -3 electron density. The local thermodynamic equilibrium conditions and plasma homogeneity have been checked. The results are compared with the available experimental and theoretical data and with present Hartree-Fock calculations in LS coupling. (orig.)

  20. On the atomic state densities of plasmas produced by the "torch a injection axiale"

    NARCIS (Netherlands)

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

    1996-01-01

    The atomic state densities of helium and argon plasmas produced by the microwave driven plasma torch called the "torche à 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

  1. Plasma conditions for non-Maxwellian electron distributions in high current discharges and laser-produced plasmas

    International Nuclear Information System (INIS)

    Whitney, K.G.; Pulsifer, P.E.

    1993-01-01

    Results from the standard quasilinear theory of ion-acoustic and Langmuir plasma microturbulence are incorporated into the kinetic theory of the electron distribution function. The theory is then applied to high current discharges and laser-produced plasmas, where either the current flow or the nonlinear laser-light absorption acts, respectively, as the energy source for the microturbulence. More specifically, the theory is applied to a selenium plasma, whose charge state is determined under conditions of collisional-radiative equilibrium, and plasma conditions are found under which microturbulence strongly influences the electron kinetics. In selenium, we show that this influence extends over a wide range of plasma conditions. For ion-acoustic turbulence, a criterion is derived, analogous to one previously obtained for laser heated plasmas, that predicts when Ohmic heating dominates over electron-electron collisions. This dominance leads to the generation of electron distributions with reduced high-energy tails relative to a Maxwellian distribution of the same temperature. Ion-acoustic turbulence lowers the current requirements needed to generate these distributions. When the laser heating criterion is rederived with ion-acoustic turbulence included in the theory, a similar reduction in the laser intensity needed to produce non-Maxwellian distributions is found. Thus we show that ion-acoustic turbulence uniformly (i.e., by the same numerical factor) reduces the electrical and heat conductivities, as well as the current (squared) and laser intensity levels needed to drive the plasma into non-Maxwellian states

  2. PDX modification to produce a bean-shaped high-beta plasma

    International Nuclear Information System (INIS)

    Materna, P.; Chrzanowski, J.; Heitzenroeder, P.; Lee, K.; Pereira, M.

    1983-01-01

    Princeton's PDX tokamak is being converted to produce bean-shaped plasmas which hopefully will reach beta of 10%. The work, which is nearly complete, involves repositioning active coils, adding passive coils, and making external modifications

  3. The electromagnetic properties of plasma produced by hypervelocity impact

    Science.gov (United States)

    Zhang, Qingming; Gong, Liangfei; Ma, Yuefen; Long, Renrong; Gong, Zizheng

    2018-02-01

    The change of electron density in moving plasma in this paper is empirically determined according to multiple ground-based experimental results and the assumption of the Maxwell distribution. Moreover, the equation of the magnetic field intensity, dominated by the current due to the collective electron movement during the expansion, is presented on the basis of the Biot-Savart law, and its relationship with time and space is subsequently depicted. In addition, hypervelocity impact experiments on a 2AL12 target have been carried out using a two-stage light gas gun to accelerate a 2AL12 projectile of 6.4 mm to 6.2 km/s. Spiral coils are designed to measure the intensity of the electromagnetic field induced by this impact. The experimental results show that the magnetic field strength is an alternate pulse maintaining nearly 1 ms and its maximum is close to 15 μT, which is strong enough to interfere with the communication circuit and chip in spacecrafts. Lastly, numerical simulation of the magnetic field intensity using this experimental parameter reveals that the intensity in our estimation from our theory tends to be well consistent with the experimental data in the first peak of the pulse signal.

  4. Direct isotope ratio measurement of uranium metal by emission spectrometry on a laser-produced plasma

    International Nuclear Information System (INIS)

    Pietsch, W.; Petit, A.; Briand, A.

    1995-01-01

    The method of Optical Emission Spectrometry on a Laser-Produced Plasma (OES/LPP) at reduced pressure has been studied for the determination of the uranium isotope ratio ( 235 U/ 238 U). Spectral profiles of the investigated transition U-II 424.437 nm show the possibility to obtain an isotopic spectral resolution in a laser-produced plasma under exactly defined experimental conditions. Spectroscopic data and results are presented. (author)

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

    Science.gov (United States)

    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.

  6. Test of models for electron transport in laser produced plasmas

    International Nuclear Information System (INIS)

    Colombant, D.G.; Manheimer, W.M.; Busquet, M.

    2005-01-01

    This paper examines five different models of electron thermal transport in laser produced spherical implosions. These are classical, classical with a flux limit f, delocalization, beam deposition model, and Fokker-Planck solutions. In small targets, the results are strongly dependent on f for flux limit models, with small f's generating very steep temperature gradients. Delocalization models are characterized by large preheat in the center of the target. The beam deposition model agrees reasonably well with the Fokker-Planck simulation results. For large, high gain fusion targets, the delocalization model shows the gain substantially reduced by the preheat. However, flux limitation models show gain largely independent of f, with the beam deposition model also showing the same high gain

  7. Ultrafast gated imaging of laser produced plasmas using the optical Kerr effect

    International Nuclear Information System (INIS)

    Symes, D. R.; Wegner, U.; Ahlswede, H.-C.; Streeter, M. J. V.; Gallegos, P. L.; Divall, E. J.; Rajeev, P. P.; Neely, D.; Smith, R. A.

    2010-01-01

    Optical imaging is a versatile diagnostic for investigations of plasmas generated under intense laser irradiation. Electro-optic gating techniques operating on the >100 ps timescale are commonly used to reduce the amount of light detected from self-emission of hot plasma or improve the temporal resolution of the detector. The use of an optical Kerr gate enables a superior dynamic range and temporal resolution compared to electronically gated devices. The application of this method for enhanced imaging of laser produced plasmas with gate time ∼100 fs is demonstrated, and the possibility to produce a sub-10 fs, high dynamic range 'all optical' streak camera is discussed.

  8. Charge-exchange-induced formation of hollow atoms in high-intensity laser-produced plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Rosmej, F.B. [TU-Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); Faenov, A.Ya.; Pikuz, T.A.; Magunov, A.I.; Skobelev, I.Yu. [Multicharged Ions Spectra Data Center of VNIIFTRI, Mendeleevo (Russian Federation); Auguste, T.; D' Oliveira, P.; Hulin, S.; Monot, P. [Commissariat a lEnergie Atomique DSM/DRECAM/SPAM, Gif-Sur-Yvette Cedex (France); Andreev, N.E.; Chegotov, M.V.; Veisman, M.E. [High Energy Density Research Centre, Institute of High Temperatures of Russian Academy of Sciences, Moscow (Russian Federation)

    1999-03-14

    For the first time registration of high-resolution soft x-ray emission and atomic data calculations of hollow-atom dielectronic satellite spectra of highly charged nitrogen have been performed. Double-electron charge-exchange processes from excited states are proposed for the formation of autoionizing levels nln'l' in high-intensity laser-produced plasmas, when field-ionized ions penetrate into the residual gas. Good agreement is found between theory and experiment. Plasma spectroscopy with hollow ions is proposed and a temperature diagnostic for laser-produced plasmas in the long-lasting recombining regime is developed. (author). Letter-to-the-editor.

  9. Characteristics of an elongated plasma column produced by magnetically coupled hollow cathode plasma source

    Science.gov (United States)

    Bhuva, M. P.; Karkari, S. K.; Kumar, Sunil

    2018-03-01

    An elongated plasma column in the presence of an axial magnetic field has been formed using a cylindrical hollow cathode (HC) and a constricted anode (CA). The plasma characteristics of the central line have been found to vary with the magnetic field strength and the axial distance from the source. It is believed that the primary electrons constituting the discharge current are steered by the axial magnetic field to undertake ionizing collisions along the plasma column. The current carrying electrons from the HC reach the anode by cross-field diffusion towards the central line. The above observation has been substantiated using a phenomenological model which links the observed characteristics of the source with the plasma column. The experimental results are found to be in qualitative agreement with the model.

  10. Expansion of laser-produced plasmas into vacuum and ambient gases

    International Nuclear Information System (INIS)

    Williams, T.

    2001-01-01

    Presented in this thesis are observations recorded using optical absorption spectroscopy, laser induced fluorescence imaging and Langmuir probe techniques for a low temperature laser-produced plasma. The plasma was generated using a KrF (248 nm, 30ns) excimer laser system focused onto a solid target surface (Ti, Mg) housed within a vacuum chamber. Plasma studies were made within vacuum (x10 -5 mTorr) and low pressure ( 2 and Ar ambient gas environments. Experimental results from a volumetric integration technique for plasma species number densities are used to yield total plume content for a laser-produced plasma in vacuum. This was used to determine the threshold power density for titanium neutral species formation. Temporally resolved electron number densities were determined using a Langmuir probe technique, for a titanium plasma generated under 532 nm and 248 nm ablation, for similar power densities and spot geometries. In this case the ablation thresholds for titanium are determined in terms of average power density and peak power density. Plume opacity problems which limit OAS and LIF diagnostic techniques are minimised using novel ablations configurations. Both techniques used, the 'composite target' and the 'plasma-jet' configurations, rely on reducing the optical thickness of the plume. The plasma-jets produced were allowed to interact with an ambient argon background and the ion/neutral ratio of the plasma-jet determined. Laser-produced plasma interactions with a d.c. biased copper mesh ∼15 mm in front of the target surface are observed. Self-emission studies of plume interactions with the mesh are monitored for positive and negative biases. Also ground-state neutral and ion interactions with the mesh are observed using OAS and LIF techniques to study individual species effects. A simple model was used to predict the perturbations to charged species distributions resulting from positive and negative applied potentials, but more complex interaction

  11. Numerical investigation of aerodynamic flow actuation produced by surface plasma actuator on 2D oscillating airfoil

    Directory of Open Access Journals (Sweden)

    Minh Khang Phan

    2016-08-01

    Full Text Available Numerical simulation of unsteady flow control over an oscillating NACA0012 airfoil is investigated. Flow actuation of a turbulent flow over the airfoil is provided by low current DC surface glow discharge plasma actuator which is analytically modeled as an ion pressure force produced in the cathode sheath region. The modeled plasma actuator has an induced pressure force of about 2 kPa under a typical experiment condition and is placed on the airfoil surface at 0% chord length and/or at 10% chord length. The plasma actuator at deep-stall angles (from 5° to 25° is able to slightly delay a dynamic stall and to weaken a pressure fluctuation in down-stroke motion. As a result, the wake region is reduced. The actuation effect varies with different plasma pulse frequencies, actuator locations and reduced frequencies. A lift coefficient can increase up to 70% by a selective operation of the plasma actuator with various plasma frequencies and locations as the angle of attack changes. Active flow control which is a key advantageous feature of the plasma actuator reveals that a dynamic stall phenomenon can be controlled by the surface plasma actuator with less power consumption if a careful control scheme of the plasma actuator is employed with the optimized plasma pulse frequency and actuator location corresponding to a dynamic change in reduced frequency.

  12. Initiation of an early-stage plasma during picosecond laser ablation of solids

    International Nuclear Information System (INIS)

    Mao, Samuel S.; Mao, Xianglei; Greif, Ralph; Russo, Richard E.

    2000-01-01

    Picosecond time-resolved images of plasma initiation were recorded during pulsed-laser ablation of metal targets in an air atmosphere. An early-stage plasma was observed to form before the release of a material vapor plume. Close to the target surface, interferometry measurements indicate that the early-stage plasma has an electron number density on the order of 10 20 cm -3 . The longitudinal expansion of the ionization front for this plasma has a velocity 10 9 cm/s, during the laser pulse. In contrast, a material--vapor plume forms approximately 200 ps after the laser pulse, and it moves away from the target at 10 6 cm/s. The experimental observations of the early-stage plasma were simulated by using a theoretical model based on a two-fluids description of laser plasmas. The results indicate that the initiation of the plasma is due to air breakdown assisted by electron emission from the target

  13. Combination of graph heuristics in producing initial solution of curriculum based course timetabling problem

    Science.gov (United States)

    Wahid, Juliana; Hussin, Naimah Mohd

    2016-08-01

    The construction of population of initial solution is a crucial task in population-based metaheuristic approach for solving curriculum-based university course timetabling problem because it can affect the convergence speed and also the quality of the final solution. This paper presents an exploration on combination of graph heuristics in construction approach in curriculum based course timetabling problem to produce a population of initial solutions. The graph heuristics were set as single and combination of two heuristics. In addition, several ways of assigning courses into room and timeslot are implemented. All settings of heuristics are then tested on the same curriculum based course timetabling problem instances and are compared with each other in terms of number of population produced. The result shows that combination of saturation degree followed by largest degree heuristic produce the highest number of population of initial solutions. The results from this study can be used in the improvement phase of algorithm that uses population of initial solutions.

  14. Late-time particle emission from laser-produced graphite plasma

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-09-01

    We report a late-time ''fireworks-like'' particle emission from laser-produced graphite plasma during its evolution. Plasmas were produced using graphite targets excited with 1064 nm Nd: yttrium aluminum garnet (YAG) laser in vacuum. The time evolution of graphite plasma was investigated using fast gated imaging and visible emission spectroscopy. The emission dynamics of plasma is rapidly changing with time and the delayed firework-like emission from the graphite target followed a black-body curve. Our studies indicated that such firework-like emission is strongly depended on target material properties and explained due to material spallation caused by overheating the trapped gases through thermal diffusion along the layer structures of graphite.

  15. Late-time particle emission from laser-produced graphite plasma

    International Nuclear Information System (INIS)

    Harilal, S. S.; Hassanein, A.; Polek, M.

    2011-01-01

    We report a late-time ''fireworks-like'' particle emission from laser-produced graphite plasma during its evolution. Plasmas were produced using graphite targets excited with 1064 nm Nd: yttrium aluminum garnet (YAG) laser in vacuum. The time evolution of graphite plasma was investigated using fast gated imaging and visible emission spectroscopy. The emission dynamics of plasma is rapidly changing with time and the delayed firework-like emission from the graphite target followed a black-body curve. Our studies indicated that such firework-like emission is strongly depended on target material properties and explained due to material spallation caused by overheating the trapped gases through thermal diffusion along the layer structures of graphite.

  16. On electromagnetic wave propagation through a plasma sheath produced by a moving ionization source

    International Nuclear Information System (INIS)

    Semenova, V.I.

    1977-01-01

    Features of the interaction of electromagnetic waves are considered with a nonstationary plasma layer of a finite thickness, produced in an immovable gas by a movable ionization source. It is shown that a static magnetic field excited on the ionization front in build-up of electrons produced in the incident wave field reemits the energy to the electromagnetic wave during the plasma relaxation caused by recombination processes. As a result the electromagnetic wave of a finite amplitude may propagate behind the nonstationary layer of an ''opaque'' (ωsub(p)sup(2)>>ωsub(urc)sup((0))sup(2)) plasma as distinct from the layer of a movable stationary plasma with the same parameters

  17. Laser-produced dense plasma in extremely high pressure gas and its application to a plasma-bridged gap switch

    International Nuclear Information System (INIS)

    Yamada, J.; Okuda, A.

    1989-01-01

    When an extremely high pressure gas is irradiated by an intense laser light, a dense plasma produced at the focal spot moves towards the focusing lens with a high velocity. Making use of this phenomenon, a new plasma-bridged gap switch is proposed and its switching characteristics is experimentally examined. From the experiments, it is confirmed that the switching time is almost constant with the applied voltage only when the focal spot is just on the positive electrode, indicating that the bridging of gap is caused by the laser light. (author)

  18. Investigation of micro-plasma in physiological saline produced by a high-power YAG laser

    International Nuclear Information System (INIS)

    Lu Jian; Ni Xiaowu; He Anzhi

    1994-01-01

    Micro-plasma and shock waves in the physiological saline produced by a Q-switched pulse YAG laser with nearby optical breakdown threshold energy are investigated by using optical shadowing exploring method, and a series of optical shadow graphs of micro-plasma and shock waves versus the incident laser energy and the delay time are obtained. Influence of mechanical action of shock waves for the high-power pulse laser on the ophthalmic treatment is discussed

  19. An isotopic analysis process with optical emission spectrometry on a laser-produced plasma

    International Nuclear Information System (INIS)

    Mauchien, P.; Pietsch, W.; Petit, A.; Briand, A.

    1994-01-01

    The sample that is to be analyzed is irradiated with a laser beam to produce a plasma at the sample surface; the spectrum of the light emitted by the plasma is analyzed and the isotope composition of the sample is derived from the spectrometry. The process is preferentially applied to uranium and plutonium; it is rapid, simpler and cheaper than previous methods, and may be applied to 'in-situ' isotopic analysis in nuclear industry. 2 figs

  20. Kinetic magnetization by fast electrons in laser-produced plasmas at sub-relativistic intensities

    Czech Academy of Sciences Publication Activity Database

    Pisarczyk, T.; Gus'kov, S. Yu.; Chodukowski, T.; Dudžák, Roman; Korneev, Ph.; Demchenko, N. N.; Kalinowska, Z.; Dostál, Jan; Zaras-Szydlowska, A.; Borodziuk, S.; Juha, Libor; Cikhardt, Jakub; Krása, Josef; Klír, Daniel; Cikhardtová, B.; Kubeš, P.; Krouský, Eduard; Krůs, Miroslav; Ullschmied, Jiří; Jungwirth, Karel; Hřebíček, Jan; Medřík, Tomáš; Golasowski, Jiří; Pfeifer, Miroslav; Renner, Oldřich; Singh, Sushil K.; Kar, S.; Ahmed, H.; Skála, Jiří; Pisarczyk, P.

    2017-01-01

    Roč. 24, č. 10 (2017), s. 1-11, č. článku 102711. ISSN 1070-664X R&D Projects: GA MŠk EF15_008/0000162 EU Projects: European Commission(XE) 654148 - LASERLAB-EUROPE Grant - others:ELI Beamlines(XE) CZ.02.1.01/0.0/0.0/15_008/0000162 Institutional support: RVO:68378271 ; RVO:61389021 Keywords : laser-produced plasma * femtosecond polaro-interferometry * spontaneous magnetic fiel * spatial and temporal electron density distribution Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.115, year: 2016

  1. Spectroscopic observations in the visible and near ultraviolet of a laser-produced plasma

    International Nuclear Information System (INIS)

    Zago, A.; Tondello, G.

    1985-01-01

    The emission from a plasma produced by laser focusing on plane targets of the elements Be, B, C and N has been observed in the visible and near ultraviolet. The spectra have been recorded mainly with an optical multichannel analyser allowing great sensitivity of detection. Both continua and line emission have been analysed in terms of plasma properties. Very broad lines of the type Δn = 1 appear prominent in the spectrum and, through their Stark broadening, the electron density of the plasma has been derived

  2. Spectroscopic observations in the visible and near ultraviolet of a laser-produced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Zago, A.; Tondello, G.

    1985-01-11

    The emission from a plasma produced by laser focusing on plane targets of the elements Be, B, C and N has been observed in the visible and near ultraviolet. The spectra have been recorded mainly with an optical multichannel analyser allowing great sensitivity of detection. Both continua and line emission have been analysed in terms of plasma properties. Very broad lines of the type ..delta..n = 1 appear prominent in the spectrum and, through their Stark broadening, the electron density of the plasma has been derived.

  3. Cracks and nanodroplets produced on tungsten surface samples by dense plasma jets

    Science.gov (United States)

    Ticoş, C. M.; Galaţanu, M.; Galaţanu, A.; Luculescu, C.; Scurtu, A.; Udrea, N.; Ticoş, D.; Dumitru, M.

    2018-03-01

    Small samples of 12.5 mm in diameter made from pure tungsten were exposed to a dense plasma jet produced by a coaxial plasma gun operated at 2 kJ. The surface of the samples was analyzed using a scanning electron microscope (SEM) before and after applying consecutive plasma shots. Cracks and craters were produced in the surface due to surface tensions during plasma heating. Nanodroplets and micron size droplets could be observed on the samples surface. An energy-dispersive spectroscopy (EDS) analysis revealed that the composition of these droplets coincided with that of the gun electrode material. Four types of samples were prepared by spark plasma sintering from powders with the average particle size ranging from 70 nanometers up to 80 μm. The plasma power load to the sample surface was estimated to be ≈4.7 MJ m-2 s-1/2 per shot. The electron temperature and density in the plasma jet had peak values 17 eV and 1.6 × 1022 m-3, respectively.

  4. Final Technical Report: Magnetic Reconnection in High-Energy Laser-Produced Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Germaschewski, Kai [Univ. of New Hampshire, Durham, NH (United States); Fox, William [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Bhattacharjee, Amitava [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

    2017-04-06

    This report describes the final results from the DOE Grant DE-SC0007168, “Fast Magnetic Reconnection in HED Laser-Produced Plasmas.” The recent generation of laboratory high-energy-density physics facilities has opened significant physics opportunities for experimentally modeling astrophysical plasmas. The goal of this proposal is to use these new tools to study fundamental problems in plasma physics and plasma astrophysics. Fundamental topics in this area involve study of the generation, amplification, and fate of magnetic fields, which are observed to pervade the plasma universe and govern its evolution. This project combined experiments at DOE laser facilities with kinetic plasma simulation to study these processes. The primary original goal of the project was to study magnetic reconnection using a new experimental platform, colliding magnetized laser-produced plasmas. However through a series of fortuitous discoveries, the work broadened out to allow significant advancement on multiple topics in laboratory astrophysics, including magnetic reconnection, Weibel instability, and collisionless shocks.

  5. High beta capture and mirror confinement of laser produced plasmas. Final report

    International Nuclear Information System (INIS)

    Haught, A.F.; Tomlinson, R.G.; Ard, W.B.; Boedeker, L.R.; Churchill, T.L.; Fader, W.J.; Jong, R.A.; Mensing, A.E.; Polk, D.H.; Stufflebeam, J.H.

    1977-12-01

    The LITE fusion plasma research program at UTRC has been investigating the stabilization and confinement physics of a mirror plasma created by energetic neutral beam heating of a confined target plasma. During the period covered by this report work has been concentrated on the investigation of hot ion losses in a warm target plasma, development of a cryocondensation pump for the LITE beam line neutralizer, theoretical studies of ECRH modification of the ambipolar potential in mirror plasmas, and analysis of the effects of localized cold plasma on DCLC stabilization. The results of these investigations are summarized below and detailed in four papers which comprise the body of this report. Measurements of the lifetime of hot ions in a mirror confined warm plasma have been carried out by observations of the hot ion buildup time obtained with energetic neutral beam injection. A cryocondensation pump of novel design has been constructed and incorporated in the neutralizer chamber of the LITE neutral beam line. Calculations have been carried out to evaluate the sizes and shapes of ambipolar potential modification produced by electron cyclotron resonance heated electrons and to determine the spatial distribution and densities of cold ions trapped in the potential wells. The effects of the spatial distribution of the cold ions on their effectiveness for stabilizing the drift cyclotron loss cone instability has been studied numerically using the formulation of Pearlstein in which the dispersion relation for the DCLC mode is solved for finite-size plasmas containing hot and cold components

  6. Dynamics expansion of laser produced plasma with different materials in magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Rabia Qindeel; Noriah Bte Bidin; Yaacob Mat daud [Laser Technology Laboratory, Physics Department, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia)], E-mail: plasmaqindeel@yahoo.com

    2008-12-01

    The dynamics expansion of the plasma generated by laser ablation of different materials has been investigated. The dynamics and confinement of laser generated plasma plumes are expanding across variable magnetic fields. A Q-switched neodymium-doped yttrium aluminum garnet laser with 1064 nm, 8 ns pulse width and 0.125 J laser energy was used to generate plasma that was allowed to expand across variable magnetic within 0.1 - 0.8 T. The expansions of laser-produced plasma of different materials are characterized by using constant laser power. CCD video camera was used to visualize and record the activities in the focal region. The plasma plume length, width and area were measured by using Matrox Inpector 2.1 and video Test 0.5 software. Spectrums of plasma beam from different materials are studied via spectrometer. The results show that the plasma generated by aluminum target is the largest than Brass and copper. The optical radiation from laser generated plasma beam spectrums are obtained in the range of UV to visible light.

  7. Experimental setup for producing tungsten coated graphite tiles using plasma enhanced chemical vapor deposition technique for fusion plasma applications

    International Nuclear Information System (INIS)

    Chauhan, Sachin Singh; Sharma, Uttam; Choudhary, K.K.; Sanyasi, A.K.; Ghosh, J.; Sharma, Jayshree

    2013-01-01

    Plasma wall interaction (PWI) in fusion grade machines puts stringent demands on the choice of materials in terms of high heat load handling capabilities and low sputtering yields. Choice of suitable material still remains a challenge and open topic of research for the PWI community. Carbon fibre composites (CFC), Beryllium (Be), and Tungsten (W) are now being considered as first runners for the first wall components of future fusion machines. Tungsten is considered to be one of the suitable materials for the job because of its superior properties than carbon like low physical sputtering yield and high sputter energy threshold, high melting point, fairly high re-crystallization temperature, low fuel retention capabilities, low chemical sputtering with hydrogen and its isotopes and most importantly the reparability with various plasma techniques both ex-situ and in-situ. Plasma assisted chemical vapour deposition is considered among various techniques as the most preferable technique for fabricating tungsten coated graphite tiles to be used as tokamak first wall and target components. These coated tiles are more favourable compared to pure tungsten due to their light weight and easier machining. A system has been designed, fabricated and installed at SVITS, Indore for producing tungsten coated graphite tiles using Plasma Enhanced Chemical Vapor Deposition (PE-CVD) technique for Fusion plasma applications. The system contains a vacuum chamber, a turbo-molecular pump, two electrodes, vacuum gauges, mass analyzer, mass flow controllers and a RF power supply for producing the plasma using hydrogen gas. The graphite tiles will be put on one of the electrodes and WF6 gas will be inserted in a controlled manner in the hydrogen plasma to achieve the tungsten-coating with WF6 dissociation. The system is integrated at SVITS, Indore and a vacuum of the order of 3*10 -6 is achieved and glow discharge plasma has been created to test all the sub-systems. The system design with

  8. Simulations of X-ray transmission through laser-produced plasmas

    International Nuclear Information System (INIS)

    Yan Jun; Qu Yizhi; Li Jiaming

    1999-01-01

    Using the detailed configuration accounting with the term structures treated by the unresolved transition array model, the authors present a method to calculate the transmission spectra for high-power laser-produced plasmas in local thermodynamic equilibrium. Based on the quantum defect theory, the UTA parameters with high principal quantum numbers can be conveniently calculated with much less computational efforts. This ensure us to handle a huge number of transition arrays from many configurations occurring in typical laser-produced middle-Z and high-Z plasmas

  9. Optical spectroscopy of laser-produced plasmas for standoff isotopic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Harilal, Sivanandan S.; Brumfield, Brian E.; LaHaye, Nicole L.; Hartig, Kyle C.; Phillips, Mark C.

    2018-04-20

    This review article covers the present status of isotope detection through emission, absorption, and fluorescence spectroscopy of atoms and molecules in a laser-produced plasma formed from a solid sample. A description of the physics behind isotope shifts in atoms and molecules is presented, followed by the physics behind solid sampling of laser ablation plumes, optical methods for isotope measurements, the suitable physical conditions of laser-produced plasma plumes for isotopic analysis, and the current status. Finally, concluding remarks will be made on the existing gaps between previous works in the literature and suggestions for future work.

  10. Initial measurements of two- and three-dimensional ordering, waves, and plasma filamentation in the Magnetized Dusty Plasma Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Edward, E-mail: etjr@auburn.edu; Konopka, Uwe [Physics Department, Auburn University, Auburn, Alabama 36849 (United States); Merlino, Robert L. [Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242 (United States); Rosenberg, Marlene [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)

    2016-05-15

    The Magnetized Dusty Plasma Experiment at Auburn University has been operational for over one year. In that time, a number of experiments have been performed at magnetic fields up to B = 2.5 T to explore the interaction between magnetized plasmas and charged, micron-sized dust particles. This paper reports on the initial results from studies of: (a) the formation of imposed, ordered structures, (b) the properties of dust wave waves in a rotating frame, and (c) the generation of plasma filaments.

  11. X-ray spectroscopic characterization of laser produced hot dense plasmas

    International Nuclear Information System (INIS)

    Kontogiannopoulos, N.

    2007-12-01

    In this work we performed experiments of emission and absorption spectroscopy of laser produced plasmas, to provide well characterized spectral data which permit to benchmark atomic physics codes. More precisely, we produced xenon and krypton plasmas in NLTE (non local thermodynamic equilibrium) conditions and studied their emission spectra. In a second experiment, we characterized the absorption spectra of zinc sulfide and aluminium plasmas in LTE (local thermodynamic equilibrium) conditions.The first two chapters give an outline of the theory involved in the study of the emission and absorption plasma spectroscopy. Chapter 1 describes the different atomic processes occurring in a plasma. The LTE and the NLTE statistics ruling the equilibrium of the atomic processes are presented. Then, we give a brief description of the different codes of plasma atomic physics used in the analysis of our experimental data, namely HULLAC, SCO and TRANSPEC/AVERROES. In Chapter 2 the macroscopic theory of the radiation transport through a plasma is given. We describe also the self-similar model of Basko and the view factor approach, which permits us to calculate the heating conditions of the absorption foils achieved in the interior of the spherical gold cavity. Chapter 3 gives a description of the instruments used for realizing the two experiments, as well as the technical characteristics of the LULI2000 laser facility used to perform the experiments. Chapter 4 presents the experiment realized to characterize the emission spectra of the xenon and krypton plasmas in NLTE, as well the analysis of the experimental data with TRANSPEC/AVERROES. Finally, the experiment for measuring the absorption spectrum of the ZnS plasma mixture and the analysis of the experimental data with the code SCO are given in Chapter 5

  12. Experimental studies of the effect target geometry on the evolution of laser produced plasma plumes

    Science.gov (United States)

    Beatty, Cuyler; Anderson, Austin; Iratcabal, Jeremy; Dutra, Eric; Covington, Aaron

    2016-10-01

    The expansion of the laser plumes was shown to be dependent on the initial target geometry. A 16 channel framing camera was used to record the plume shape and propagation speeds were determined from analysis of the images. Plastic targets were manufactured using different methods including 3D printing, CNC machining and vacuum casting. Preliminary target designs were made using a 3D printer and ABS plastic material. These targets were then tested using a 3 J laser with a 5 ns duration pulse. Targets with a deep conical depression were shown to produce highly collimated plumes when compared to flat top targets. Preliminary results of these experiments will be discussed along with planned future experiments that will use the indented targets with a 30 J laser with a 0.8 ns duration pulse in preparation for pinched laser plume experiments at the Nevada Terawatt Facility. Other polymers that are readily available in a deuterated form will also be explored as part of an effort to develop a cost effective plasma plume target for follow on neutron production experiments. Dr. Austin Anderson.

  13. Characterization of long-scale-length plasmas produced from plastic foam targets for laser plasma instability (LPI) research

    Science.gov (United States)

    Oh, Jaechul; Weaver, J. L.; Serlin, V.; Obenschain, S. P.

    2017-10-01

    We report on an experimental effort to produce plasmas with long scale lengths for the study of parametric instabilities, such as two plasmon decay (TPD) and stimulated Raman scattering (SRS), under conditions relevant to fusion plasma. In the current experiment, plasmas are formed from low density (10-100 mg/cc) CH foam targets irradiated by Nike krypton fluoride laser pulses (λ = 248 nm, 1 nsec FWHM) with energies up to 1 kJ. This experiment is conducted with two primary diagnostics: the grid image refractometer (Nike-GIR) to measure electron density and temperature profiles of the coronas, and time-resolved spectrometers with absolute intensity calibration to examine scattered light features of TPD or SRS. Nike-GIR was recently upgraded with a 5th harmonic probe laser (λ = 213 nm) to access plasma regions near quarter critical density of 248 nm light (4.5 ×1021 cm-3). The results will be discussed with data obtained from 120 μm scale-length plasmas created on solid CH targets in previous LPI experiments at Nike. Work supported by DoE/NNSA.

  14. Atomic data of Ti II from laser produced Ti plasmas by optical emission spectroscopy

    International Nuclear Information System (INIS)

    Refaie, A.I.; Farrag, A.A.; El Sharkawy, H.; El Sherbini, T.M.

    2005-06-01

    In the present study, the emission spectrum of titanium produced from laser induced plasma has been measured at different distances from the target. The Titanium target is irradiated by using the high power Q-switched Nd:YAG laser (λ=1064 nm) that generates energy 750 mJ/pulse of duration rate 6 ns and repetition rate 10 Hz in vacuum and at different distances. The variation of the distance from the target affects the measured plasma parameters, i.e. the electron density, the ion temperature and the velocity distribution. The electron density increases with the increase of the distance from the target. At a distance 0.6 mm from the target it decreases to 2.28·10 16 cm -3 . The temperature increases with the distance from the get until a distance of 1 mm, after that it decreases. It is found that the plasma velocity increases with the distance then it decreases again. Then, Energy levels and transition probabilities for 3d 2 4p →(3d 2 4s + 3d 3 ) lines have been determined by measurement of emission line intensities from an optically thin laser produced plasma of Ti II in vacuum. Calculations with intermediate coupling using Hartree-Fock wave functions have been carried out in order to place the experimental data on an absolute scale and also to evaluate the lifetimes. The plasma parameters in different regions of the plasma plume have been measured and used to obtain further transition probabilities. (author)

  15. A Novel Spectrometer for Measuring Laser-Produced Plasma X-Ray in Inertial Confinement Fusion

    Directory of Open Access Journals (Sweden)

    Zhu Gang

    2012-01-01

    Full Text Available In the experimental investigations of inertial confinement fusion, the laser-produced high-temperature plasma contains very abundant information, such as the electron temperature and density, ionization. In order to diagnose laser-plasma distribution in space and evolution in time, an elliptical curved crystal spectrometer has been developed and applied to diagnose X-ray of laser-produced plasma in 0.2~2.46 nm region. According to the theory of Bragg diffraction, four kinds of crystal including LiF, PET, MiCa, and KAP were chosen as dispersive elements. The distance of crystal lattice varies from 0.4 to 2.6 nm. Bragg angle is in the range of 30°~67.5°, and the spectral detection angle is in 55.4°~134°. The curved crystal spectrometer mainly consists of elliptical curved crystal analyzer, vacuum configuration, aligning device, spectral detectors and three-dimensional microadjustment devices. The spectrographic experiment was carried out on the XG-2 laser facility. Emission spectrum of Al plasmas, Ti plasma, and Au plasmas have been successfully recorded by using X-ray CCD camera. It is demonstrated experimentally that the measured wavelength is accorded with the theoretical value.

  16. Influence of the laser pulse duration on laser-produced plasma properties

    International Nuclear Information System (INIS)

    Drogoff, B Le; Margot, J; Vidal, F; Laville, S; Chaker, M; Sabsabi, M; Johnston, T W; Barthelemy, O

    2004-01-01

    In the framework of laser-induced plasma spectroscopy (LIPS) applications, time-resolved characteristics of laser-produced aluminium plasmas in air at atmospheric pressure are investigated for laser pulse durations ranging from 100 fs to 270 ps. Measurements show that for delays after the laser pulse longer than ∼100 ns, the plasma temperature increases slightly with the laser pulse duration, while the electron density is independent of it. In addition, as the pulse duration increases, the plasma radiation emission lasts longer and the spectral lines arise later from the continuum emission. The time dependence of the continuum emission appears to be similar whatever the duration of the laser pulse is, while the temporal evolution of the line emission seems to be affected mainly by the plasma temperature. Finally, as far as spectrochemical applications (such as LIPS) of laser-produced plasmas are concerned, this study highlights the importance of the choice of appropriate temporal gating parameters for each laser pulse duration

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

    International Nuclear Information System (INIS)

    Craxton, R.S.; Turner, F.S.; Hoefen, R.; Darrow, C.; Gabl, E.F.; Busch, G.E.

    1993-01-01

    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 ∼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

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

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, M. J., E-mail: mros@lle.rochester.edu; Li, C. K.; Séguin, F. H.; Frenje, J. A.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Fox, W. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Igumenshchev, I.; Stoeckl, C.; Glebov, V. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Town, R. P. J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2015-04-15

    Novel experiments to study the strongly-driven collision of parallel magnetic fields in β ∼ 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 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.

  19. Producing High Intense Attosecond Pulse Train by Interaction of Three-Color Pulse and Overdense Plasma

    Science.gov (United States)

    Salehi, M.; Mirzanejad, S.

    2017-05-01

    Amplifying the attosecond pulse by the chirp pulse amplification method is impossible. Furthermore, the intensity of attosecond pulse is low in the interaction of laser pulse and underdense plasma. This motivates us to propose using a multi-color pulse to produce the high intense attosecond pulse. In the present study, the relativistic interaction of a three-color linearly-polarized laser-pulse with highly overdense plasma is studied. We show that the combination of {{ω }}1, {{ω }}2 and {{ω }}3 frequencies decreases the instance full width at half maximum reflected attosecond pulse train from the overdense plasma surface. Moreover, we show that the three-color pulse increases the intensity of generated harmonics, which is explained by the relativistic oscillating mirror model. The obtained results demonstrate that if the three-color laser pulse interacts with overdense plasma, it will enhance two orders of magnitude of intensity of ultra short attosecond pulses in comparison with monochromatic pulse.

  20. Self-modulation and anomalous collective scattering of laser produced intense ion beam in plasmas

    Directory of Open Access Journals (Sweden)

    K. Mima

    2018-05-01

    Full Text Available The collective interaction between intense ion beams and plasmas is studied by simulations and experiments, where an intense proton beam produced by a short pulse laser is injected into a pre-ionized gas. It is found that, depending on its current density, collective effects can significantly alter the propagated ion beam and the stopping power. The quantitative agreement that is found between theories and experiments constitutes the first validation of the collective interaction theory. The effects in the interaction between intense ion beams and background gas plasmas are of importance for the design of laser fusion reactors as well as for beam physics. Keywords: Two stream instabilities, Ultra intense short pulse laser, Proton beam, Wake field, Electron plasma wave, Laser plasma interaction, PACS codes: 52.38.Kd, 29.27.Fh, 52.40.Kh, 52.70.Nc

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

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hong; Duan, Lian; Lan, Hui [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Wang, Xinbing, E-mail: xbwang@hust.edu.cn; Chen, Ziqi; Zuo, Duluo [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Lu, Peixiang [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2015-05-21

    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 μm 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.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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 μm 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

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

    International Nuclear Information System (INIS)

    Al-Shboul, K. F.; Harilal, S. S.; Hassanein, A.; Polek, M.

    2011-01-01

    We investigated the role of helium ambient gas on the dynamics of C 2 species formation in laser-produced carbon plasma. The plasma was produced by focusing 1064 nm pulses from an Nd:YAG laser onto a carbon target. The emission from the C 2 species was studied using optical emission spectroscopy, and spectrally resolved and integrated fast imaging. Our results indicate that the formation of C 2 in the plasma plume is strongly affected by the pressure of the He gas. In vacuum, the C 2 emission zone was located near the target and C 2 intensity oscillations were observed both in axial and radial directions with increasing the He pressure. The oscillations in C 2 intensity at higher pressures in the expanding plume could be caused by various formation zones of carbon dimers.

  4. Initial frequency shift of large amplitude plasma wave, 2

    International Nuclear Information System (INIS)

    Yamanaka, K.; Sugihara, R.; Ohsawa, Y.; Kamimura, T.

    1979-07-01

    A nonlinear complex frequency shift of the ion acoustic wave in the initial phase defined by 0 0 and ωsub(s)/k as long as ωsub(s) >> γsub( l), where phi 0 , ωsub(s), γsub( l) and t sub(c) are the initial value of the potential, the frequency of the wave, the linear Landau damping coefficient and the time for the first minimum of the amplitude oscillation, respectively. A simulation study is also carried out. The results confirm the validity of the theory. (author)

  5. Nonlinear processes in laser-produced dense plasma (observation of the fractional harmonics)

    International Nuclear Information System (INIS)

    Lyu, K.S.

    1988-01-01

    One of the main issues of laser plasma physics interactions is harmonic generation. The harmonic emission spectrum provides clues as to which non-linear processes take place in the plasma. Several effects contribute to a given line as judged from the complexity of the actual spectra. Unfolding of them has not been done satisfactorily yet. Harmonic lines with half integer or integer orders have been observed, but the physics are far from complete. In this dissertation research, we observed the usual second harmonic generation and a set of fractional harmonics which we believe have been observed for the first time in plasma physics. The plasma was produced by a high power laser and we have characterized its properties from the analysis of the radiation spectra, including the harmonic lines, as measured using the methods of transient spectroscopy. We produced the plasma with a Nd:glass laser which had a 65 nsec pulse width (FWHM) with a total energy of up to 6 Joules. The targets were steel alloys, copper, and aluminum. The harmonic generation from the plasma with a planar metal target was not strong. But, it became stronger when we made a dead hole (cavity) at the laser spot on the target surface. The second harmonic line appears first before the time of the peak of laser pulse. The fractional harmonics, which are related to the laser wavelength by rational number other than integers or half integers, appear near or after the time of the laser peak and weaker in UV wavelength range but stronger if some atomic emission line are near by. To understand the plasma evolution better, we developed computer simulation codes. The codes contain all relevant processes necessary to compute the plasma evolution

  6. Optical measurements of lateral energy flow and plasma motion in laser-produced plasmas

    International Nuclear Information System (INIS)

    Benjamin, R.F.; Riffle, J.H.

    1979-01-01

    An optical system consisting of a telephoto lens and multi-image camera is described and the experimental results and their implications are presented. We will also describe the opto-electronic system that will measure the time history of the energy flow with sub-nanosecond resolution. The system will be useful to study both one- and two-dimensional geometries. The third optical diagnostic is a laser probe utilizing detection by the opto-electronic system mentioned above. This diagnostic measures plasma motion as well as energy flow. The laser probe and detection system mounts directly onto the target chamber at LASLs Gemini CO 2 laser, causing severe alignment and stability problems whose solutions will be shown

  7. Intensity and shape of spectral lines from laser-produced plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Jamelot, G; Jaegle, P; Carillon, A; Wehenkel, C [Centre National de la Recherche Scientifique, 91 - Orsay (France); Paris-11 Univ., 91 - Orsay (France); Ecole Polytechnique, 91 - Palaiseau (France))

    1979-01-01

    In starting from spectral studies of multicharged ions in dense laser-produced plasmas, the main processes which determine the intensity and the shape of lines in the X-UV range are described. The role of radiation transfer is underlined. Intensity anomalies resulting from occurrence of population inversions are considered and a recent experiment performed for investigating such anomalies is described.

  8. Self-phase modulation of laser light in laser produced plasma

    International Nuclear Information System (INIS)

    Yamanaka, C.; Yamanaka, T.; Mizui, J.; Yamaguchi, N.

    1975-02-01

    A spectrum broadening due to the self-phase modulation of a laser light was observed in the laser produced deuterium and hydrogen plasma. Qualitative treatments of the density modulation due to the self-focusing process and the modulational instability were discussed. The theoretical estimation of spectrum broadening fairly accorded with the experimental results. (auth.)

  9. Fast ion emission from the plasma produced by the PALS laser system

    Czech Academy of Sciences Publication Activity Database

    Wolowski, J.; Badziak, J.; Boody, F. P.; Hora, H.; Hnatowicz, Vladimír; Jungwirth, Karel; Krása, Josef; Láska, Leoš; Parys, P.; Peřina, Vratislav; Pfeifer, Miroslav; Rohlena, Karel; Ryc, L.; Ullschmied, Jiří; Woryna, E.

    2002-01-01

    Roč. 44, - (2002), s. 1277-1283 ISSN 0741-3335 Institutional research plan: CEZ:AV0Z1048901 Keywords : emission * plasma produced * PALS laser system ? Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.121, year: 2002

  10. Technological plasma source equipped with combined system of vacuum-arc discharge initiation

    International Nuclear Information System (INIS)

    Sysoev, Yu.O.

    2013-01-01

    The construction and the operation principle of erosion plasma source with a three-stage system of vacuum-arc discharge excitation is described. As first two step was used the modified contactless start system with plasma injector, which was widely used in standard plasma sources of the ''Bulat'' systems. The operation principle of the third stage was based on the transition of glow discharge to arc discharge. Coordinated operation of three stages during various stages of coating deposition provided significant increasing of service life and reliability of the system of vacuum-arc discharge initiation and extended the functionality of the plasma source

  11. Experimental study of the initial plasma formation stage in a linear theta pinch of inverted field

    International Nuclear Information System (INIS)

    Casin, G.C.; Alvarez, Ricardo; Rojkind, R.H.; Rodrigo, A.B.

    1986-01-01

    The initial stage of the plasma formation was studied in a linear theta pinch. Experiments were made to determine the machine operating conditions for good shot-to-shot reproducibility. Spectroscopic measurements of electron density and of electron and ion temperature were made afterwards to characterize the plasma at different stages of its heating process. The results obtained indicate that shot-to-shot reproducibility is strongly influenced by the presence of impurities and by the plasma preionization technique used. Under proper operating conditions, excellent reproducibility was observed. The measured values of the plasma parameters are compatible with those determined for similar machines. (Author) [es

  12. Interferometric investigation of shock waves induced by a TEA-CO2 laser produced plasma in air in front of a solid target

    International Nuclear Information System (INIS)

    Apostol, D.; Apostol, I.; Cojocaru, E.; Draganescu, V.; Mihailescu, N.I.; Morjan, I.; Konov, I.V.

    1979-06-01

    The shock waves induced in the surrounding atmosphere by an air plasma were investigated by laser interferometry. The air breakdown plasma was produced by a TEA-CO 2 laser in front of a solid target. The results were compared to the predictions of theory of intense explosions in gases and a good agreement was inferred. It was also determined that the symmetry of the expansion of the initial shock wave is determined by the plasma source shape and, accordingly, depends on the laser power density incident on the target surface. However, for further stages all the shock waves expand spherically. (author)

  13. Spectral lines and characteristic of temporal variations in photoionized plasmas induced with laser-produced plasma extreme ultraviolet source

    Science.gov (United States)

    Saber, I.; Bartnik, A.; Wachulak, P.; Skrzeczanowski, W.; Jarocki, R.; Fiedorowicz, H.

    2017-11-01

    Spectral lines for Kr/Ne/H2 photoionized plasma in the ultraviolet and visible (UV/Vis) wavelength ranges have been created using a laser-produced plasma (LPP) EUV source. The source is based on a double-stream gas puff target irradiated with a commercial Nd:YAG laser. The laser pulses were focused onto a gas stream, injected into a vacuum chamber synchronously with the EUV pulses. Spectral lines from photoionization in neutral Kr/Ne/H2 and up to few charged states were observed. The intense emission lines were associated with the Kr transition lines. Experimental and theoretical investigations on intensity variations for some ionic lines are presented. A decrease in the intensity with the delay time between the laser pulse and the spectrum acquisition was revealed. Electron temperature and electron density in the photoionized plasma have been estimated from the characteristic emission lines. Temperature was obtained using Boltzmann plot method, assuming that the population density of atoms and ions are considered in a local thermodynamic equilibrium (LTE). Electron density was calculated from the Stark broadening profile. The temporal evaluation of the plasma and the way of optimizing the radiation intensity of LPP EUV sources is discussed.

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

    Science.gov (United States)

    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 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 (λ = 263 nm, Δt = 10 ps) beamlets (50 μm 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.

  15. Shack-Hartmann Electron Densitometer (SHED): An Optical System for Diagnosing Free Electron Density in Laser-Produced Plasmas

    Science.gov (United States)

    2016-11-01

    Free Electron Density in Laser-Produced Plasmas by Anthony R Valenzuela Approved for public release; distribution is...AND SUBTITLE Shack-Hartmann Electron Densitometer (SHED): An Optical System for Diagnosing Free Electron Density in Laser-Produced Plasmas 5a...SUPPLEMENTARY NOTES 14. ABSTRACT The Shack-Hartmann Electron Densitometer is a novel method to diagnose ultrashort pulse laser–produced plasmas

  16. Initial frequency shift of large amplitude plasma wave

    International Nuclear Information System (INIS)

    Sugihara, Ryo; Yamanaka, Kaoru.

    1979-04-01

    A distribution function which is an exact solution to the collisionless Boltzmann equation is obtained in an expansion form in terms of the potential phi(x, t). A complex nonlinear frequency shift ωsub( n)(t) is obtained by use of the Poisson equation and the expansion. The theory is valid for arbitrary phi 0 and v sub(p) as long as ωsub(p) >> γsub( l), and in the initial phase defined by 0 0 , v sub(p), ωsub(p), γsub( l) and t sub(c) are the initial value of phi, the phase velocity, the Langmuir frequency, the linear Landau damping coefficient and the time for the first minimum of the amplitude oscillation. The ωsub( n)(0) does not vanish and Reωsub( n)(0)/γsub( l) > 1 holds even for e phi 0 /T 1 in the initial phase for v sub( p) > v sub( t). The theory reproduces main features of experimental results and that of simulations. (author)

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

    International Nuclear Information System (INIS)

    Mahdieh, M H; Gavili, A

    2003-01-01

    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 (n i >>n e ∼0), the transition region (pre-sheath) (n i = n e ), and the quasi-neutral plasma (n i -n e i ). 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

  18. Characteristics of X-ray photons in tilted incident laser-produced plasma

    International Nuclear Information System (INIS)

    Wang Ruirong; Chen Weimin; Xie Dongzhu

    2008-01-01

    Characteristics of X-ray and spout direction of heat plasma flow were studied on Shenguang-II laser facility. Using of pinhole X-ray camera, X-ray photons from the plasma of aluminum (Al) irradiated by 1.053 μm laser, was measured and analysed. It is observed that the spatial distribution of X-ray photons in Al plasma for tilted irradiation is symmetic at the center of the target. The spout direction of heat plasma flow is inferred by the distribution contour of X-ray photons. the experimental results show that the spout direction of heat plasma flow is normal to target plane and the output intensity of X-ray photons does not increase significantly for tilted laser incidence. Uniformity of laser energy deposition is improved by superposing tilted incident and laser perpendicularly incident laser. At the same time, it is found that the conversion efficiency from the tilted incident laser energy to X-ray photons of laser-produced plasma is decreased. (authors)

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

    International Nuclear Information System (INIS)

    Lee, Y.T.; London, R.A.; Zimmerman, G.B.; Haglestein, P.L.

    1989-01-01

    In this paper the authors apply the escape probability method to treat transfer of optically thick lines in laser-produced plasmas in plan-parallel geometry. They investigate the effect of self-absorption on the ionization balance and ion level populations. In addition, they calculate such effect on the laser gains in an exploding foil target heated by an optical laser. Due to the large ion streaming motion in laser-produced plasmas, absorption of an emitted photon occurs only over the length in which the Doppler shift is equal to the line width. They find that the escape probability calculated with the Doppler shift is larger compared to the escape probability for a static plasma. Therefore, the ion streaming motion contributes significantly to the line transfer process in laser-produced plasmas. As examples, they have applied escape probability to calculate transfer of optically thick lines in both ablating slab and exploding foil targets under irradiation of a high-power optical laser

  20. Measurements of hydrogen gas stopping efficiency for tin ions from laser-produced plasma

    Science.gov (United States)

    Abramenko, D. B.; Spiridonov, M. V.; Krainov, P. V.; Krivtsun, V. M.; Astakhov, D. I.; Medvedev, V. V.; van Kampen, M.; Smeets, D.; Koshelev, K. N.

    2018-04-01

    Experimental studies of stopping of ion fluxes from laser-produced plasma by a low-pressure gas atmosphere are presented. A modification of the time-of-flight spectroscopy technique is proposed for the stopping cross-sectional measurements in the ion energy range of 0.1-10 keV. The application of the proposed technique is demonstrated for Sn ion stopping by H2 gas. This combination of elements is of particular importance for the development of plasma-based sources of extreme ultraviolet radiation for lithographic applications.

  1. Spectral tomographic analysis of Bremsstrahlung X-rays generated in a laser-produced plasma

    Czech Academy of Sciences Publication Activity Database

    Rhee, Y.-J.; Nam, S. M.; Peebles, W.; Sawada, H.; Wei, M.; Vaisseau, X.; Sasaki, T.; Giuffrida, Lorenzo; Hulin, S.; Vauzour, B.; Santos, J.J.; Batani, D.; McLean, H. S.; Patel, P. K.; Li, Y.; Yuan, D. W.; Zhang, K.; Zhong, J. Y.; Fu, C. B.; Hua, N.; Li, K.; Zhang, Y.; Zhu, J. Q.; Kim, I. J.; Jeon, J. H.; Jeong, T.M.; Choi, I.W.; Lee, H. W.; Sung, J.H.; Lee, S.K.; Nam, C.H.

    2016-01-01

    Roč. 34, č. 4 (2016), s. 645-654 ISSN 0263-0346 R&D Projects: GA MŠk LQ1606; GA MŠk EF15_008/0000162 Grant - others:ELI Beamlines(XE) CZ.02.1.01/0.0/0.0/15_008/0000162 Institutional support: RVO:68378271 Keywords : Bremsstrahlung X-ray * filter stack spectrometer * laser-produced plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.420, year: 2016

  2. Development of a compact laser-produced plasma soft X-ray source for radiobiology experiments

    Czech Academy of Sciences Publication Activity Database

    Adjei, D.; Ayele, M. G.; Wachulak, P.; Bartnik, A.; Wegrzynski, L.; Fiedorowicz, H.; Vyšín, Luděk; Wiechec, A.; Lekki, J.; Kwiatek, W. M.; Pina, L.; Davídková, Marie; Juha, Libor

    2015-01-01

    Roč. 364, Dec (2015), s. 27-32 ISSN 0168-583X R&D Projects: GA ČR(CZ) GBP108/12/G108; GA ČR GA13-28721S EU Projects: European Commission(XE) 284464 - LASERLAB-EUROPE Institutional support: RVO:68378271 ; RVO:61389005 Keywords : laser-produced plasma * soft X-rays * radiobiology * gas puff target * water window Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.389, year: 2015

  3. Anomalous intensities of Ne-like ion resonance line in plasma produced by picosecond laser pulse

    International Nuclear Information System (INIS)

    Bryunetkin, B.A.; Skobelev, I.Yu.; Faenov, A.Ya.; Kalashnikov, M.P.; Nikles, P.; Shnyupep, M.

    1995-01-01

    An anomalous structure of intensities of spectral lines of CuXX and GeXXX Ne-like ions emitted by plasma produced by laser pulses of picosecond duration and up to 2x10 18 W/cm 2 flux density is recorded for the first time. It is shown that spectrum maximum of these ions is emitted from a plasma region whose density is significantly above the critical value of the length of heating laser radiation wave. 9 refs.; 3 figs

  4. CO2-laser--produced plasma columns in a solenoidal magnetic field

    International Nuclear Information System (INIS)

    Offenberger, A.A.; Cervenan, M.R.; Smy, P.R.

    1976-01-01

    A 1-GW CO 2 laser pulse has been used to produce extended column breakdown of hydrogen at low pressure in a 20-cm-long solenoid. Magnetic fields of up to 110 kG were used to inhibit radial losses of the plasma column. A differential pumping scheme was devised to prevent formation of an opaque absorption wave travelling out of the solenoid back toward the focusing lens. Target burns give direct evidence for trapped laser beam propagation along the plasma column

  5. Ultra high speed framing photographs of laser produced plasmas using a picosecond optical shutter

    International Nuclear Information System (INIS)

    Gillman, G.B.; Ramsden, S.A.

    1975-01-01

    A study has been carried out of the spatial transmission properties of the optical Kerr effect shutter and it has been used to take ultra high speed framing photographs of laser produced plasmas in air and from solid targets. With a 1cm long CS 2 cell of aperture 5cm 2 a transmission of approximately 5% and an on/off contrast ratio of 10 4 was obtained. An image intensifier was necessary to obtain adequately exposed photographs of the plasma and the overall spatial resolution of the system was approximately 2μ. (author)

  6. 4d--4f emission resonances in laser-produced plasmas

    International Nuclear Information System (INIS)

    O'Sullivan, G.; Carroll, P.K.

    1981-01-01

    Using targets containing compounds of the elements cesium through lutetium, we studied the spectra of laser-produced plasmas in the grazing-incidence region from 40 to 200 A. The spectra are characterized by strong regions of resonancelike emission extending typically over 9--18 eV. With increasing Z, the spectra show certain systematic variations in character and move monotonically toward shorter wavelengths. From a collisional-radiative plasma model, the ion stages responsible for the emision are identified as VIII through XVI. The resonances are attributed to 4-4f transitions that, because Dn = 0, tend to overlap for different ion stages of the same element

  7. Development of a compact laser-produced plasma soft X-ray source for radiobiology experiments

    Energy Technology Data Exchange (ETDEWEB)

    Adjei, Daniel, E-mail: nana.adjeidan@gmail.com [Institute of Optoelectronics, Military University of Technology, 2, Kaliskiego Str., 00-908 Warsaw (Poland); Radiation Protection Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra (Ghana); Ayele, Mesfin Getachew; Wachulak, Przemyslaw; Bartnik, Andrzej; Wegrzynski, Łukasz; Fiedorowicz, Henryk [Institute of Optoelectronics, Military University of Technology, 2, Kaliskiego Str., 00-908 Warsaw (Poland); Vyšín, Luděk [Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8 (Czech Republic); Faculty of Nuclear Sciences and Engineering Physics, Czech Technical University in Prague, Břehová 7, 115 19 Prague 1 (Czech Republic); Wiechec, Anna; Lekki, Janusz; Kwiatek, Wojciech M. [Institute of Nuclear Physics, Polish Academy of Sciences, 152, Radzikowskiego Str., 31-342 Cracow (Poland); Pina, Ladislav [Faculty of Nuclear Sciences and Engineering Physics, Czech Technical University in Prague, Břehová 7, 115 19 Prague 1 (Czech Republic); Davídková, Marie [Institute of Nuclear Physics, Czech Academy of Sciences, Řež (Czech Republic); Juha, Libor [Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8 (Czech Republic)

    2015-12-01

    A desk-top laser-produced plasma (LPP) source of soft X-rays (SXR) has been developed for radiobiology research. The source is based on a double-stream gas puff target, irradiated with the focused beam of a commercial Nd:YAG laser. The source has been optimized to get a maximum photon emission from LPP in the X-ray “water window” spectral wavelength range from 2.3 nm (i.e., an absorption edge of oxygen) to 4.4 nm (i.e., an absorption edge of carbon) (280–540 eV in photon energy units) by using argon gas-puff target and spectral filtering by free-standing thin foils. The present source delivers nanosecond pulses of soft X-rays at a fluence of about 4.2 × 10{sup 3} photons/μm{sup 2}/pulse on a sample placed inside the vacuum chamber. In this paper, the source design, radiation output characterization measurements and initial irradiation experiments are described. The source can be useful in addressing observations related to biomolecular, cellular and organisms’ sensitivity to pulsed radiation in the “water window”, where carbon atoms absorb X-rays more strongly than the oxygen, mostly present in water. The combination of the SXR source and the radiobiology irradiation layout, reported in this article, make possible a systematic investigation of relationships between direct and indirect action of ionizing radiation, an increase of a local dose in carbon-rich compartments of the cell (e.g., lipid membranes), an experimental estimation of a particular role of the Auger effect (in particular in carbon atoms) in the damage to biological systems, and the study of ionization/excitation-density (LET – Linear Energy Transfer) and dose-rate effects in radiobiology.

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

    International Nuclear Information System (INIS)

    Mirzaie, M.; Shokri, B.; Rukhadze, A. A.

    2010-01-01

    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.

  9. Spectroscopic study of plasma produced with a heavy ion maxilac beam

    International Nuclear Information System (INIS)

    Belyaev, G.E.; Golubev, A.A.; Sharkov, B.Y.; Mahrt-Olt, K.; Hoffmann, D.H.H.

    1992-01-01

    Spectroscopic study of plasma produced through bombardment of the 1 x 3 mm 2 area on the surface of a solid Mg target with Kr + ions is carried out. Spectral lines of Mg I and Mg II ions were observed in the visible range (200-600 nm). The plasma parameters N e 1.4·10 17 cm -3 and T e = 0.8 eV are calculated from electron impact broadening of the 4f-3d line of MgII and from the ratio of intensities for the 4f-3d and 4s-3p lines of Mg II. The ionic composition of the plasma is determined. The detected X-ray emission is shown to be the characteristic emission of the target. (author)

  10. Polymorphous silicon thin films produced in dusty plasmas: application to solar cells

    International Nuclear Information System (INIS)

    Roca i Cabarrocas, Pere; Chaabane, N; Kharchenko, A V; Tchakarov, S

    2004-01-01

    We summarize our current understanding of the optimization of PIN solar cells produced by plasma enhanced chemical vapour deposition from silane-hydrogen mixtures. To increase the deposition rate, the discharge is operated under plasma conditions close to powder formation, where silicon nanocrystals contribute to the deposition of so-called polymorphous silicon thin films. We show that the increase in deposition rate can be achieved via an accurate control of the plasma parameters. However, this also results in a highly defective interface in the solar cells due to the bombardment of the P-layer by positively charged nanocrystals during the deposition of the I-layer. We show that decreasing the ion energy by increasing the total pressure or by using silane-helium mixtures allows us to increase both the deposition rate and the solar cells efficiency, as required for cost effective thin film photovoltaics

  11. Behaviour of laser-produced plasma in a uniform magnetic field

    International Nuclear Information System (INIS)

    Okada, Shigefumi; Sato, Kohnosuke; Sekiguchi, Tadashi.

    1979-11-01

    A column of a laser-produced plasma is successfully made in a uniform magnetic field. The radius of the column increases and then decreases (bouncing motion). On the surface of this plasma column, where the steep density gradient exists with the scale length shorter than the ion Larmor radius, an azimuthal modulation appears in the plasma luminosity. This is indicative of the flute-like instability with the azimuthal wave number; k sub(perpendicular) -- 4 x 10 3 B sup(0.8) (in the MKSA system of units). The dispersion equation based on the linearized Vlasov equation with the local approximation is derived and the occurrence of the lower-hybrid-drift instability is predicted. A fairly good agreement between the theory and experiments is seen. (author)

  12. Electron-Beam Produced Air Plasma: Optical Measurement of Beam Current

    Science.gov (United States)

    Vidmar, Robert; Stalder, Kenneth; Seeley, Megan

    2006-10-01

    Experiments to quantify the electron beam current and distribution of beam current in air plasma are discussed. The air plasma is produced by a 100-keV 10-mA electron beam source that traverses a transmission window into a chamber with air as a target gas. Air pressure is between 1 mTorr and 760 Torr. Strong optical emissions due to electron impact ionization are observed for the N2 2^nd positive line at 337.1 nm and the N2^+ 1^st negative line at 391.4 nm. Calibration of optical emissions using signals from the isolated transmission window and a Faraday plate are discussed. The calibrated optical system is then used to quantify the electron distribution in the air plasma.

  13. Spectroscopic study of plasma produced with a heavy ion maxilac beam

    Energy Technology Data Exchange (ETDEWEB)

    Belyaev, G.E.; Golubev, A.A.; Sharkov, B.Y. (Gosudarstvennyj Komitet po Ispol' zovaniyu Atomnoj Ehnergii SSSR, Moscow (Russian Federation). Inst. Teoreticheskoj i Ehksperimental' noj Fiziki); Bryunetkin, B.A.; Skobelev, I.Y.; Faenov, A.Y. (Nauchno-Proizvostvennoe Ob' ' edinenie VNIIFTRI, Mendeleevo (Russian Federation)); Mahrt-Olt, K.; Hoffmann, D.H.H. (Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany))

    1992-01-01

    Spectroscopic study of plasma produced through bombardment of the 1 x 3 mm[sup 2] area on the surface of a solid Mg target with Kr[sup +] ions is carried out. Spectral lines of Mg I and Mg II ions were observed in the visible range (200-600 nm). The plasma parameters N[sub e] 1.4[center dot]10[sup 17] cm [sup -3] and T[sub e] = 0.8 eV are calculated from electron impact broadening of the 4f-3d line of MgII and from the ratio of intensities for the 4f-3d and 4s-3p lines of Mg II. The ionic composition of the plasma is determined. The detected X-ray emission is shown to be the characteristic emission of the target. (author).

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

    Science.gov (United States)

    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.

  15. Measurements of Laser Plasma Instability (LPI) and Electron Density/Temperature Profiles in Plasmas Produced by the Nike KrF Laser

    Science.gov (United States)

    Oh, Jaechul; Weaver, J. L.; Serlin, V.; Obenschain, S. P.

    2016-10-01

    We will present results of simultaneous measurements of LPI-driven light scattering and density/temperature profiles in CH plasmas produced by the Nike krypton fluoride laser (λ = 248 nm). The primary diagnostics for the LPI measurement are time-resolved spectrometers with absolute intensity calibration in spectral ranges relevant to the optical detection of stimulated Raman scattering or two plasmon decay. The spectrometers are capable of monitoring signal intensity relative to thermal background radiation from plasma providing a useful way to analyze LPI initiation. For further understanding of LPI processes, the recently implemented grid image refractometer (Nike-GIR)a is used to measure the coronal plasma profiles. In this experiment, Nike-GIR is equipped with a 5th harmonic probe laser (λ = 213 nm) in attempt to probe into a high density region over the previous peak density with λ = 263 nm probe light ( 4 ×1021 cm-3). The LPI behaviors will be discussed with the measured data sets. Work supported by DoE/NNSA.

  16. On- and off-axis spectral emission features from laser-produced gas breakdown plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Harilal, S. S.; Skrodzki, P. J.; Miloshevsky, A.; Brumfield, B. E.; Phillips, M. C.; Miloshevsky, G.

    2017-06-01

    Laser-heated gas breakdown plasmas or sparks emit profoundly in the ultraviolet and visible region of the electromagnetic spectrum with contributions from ionic, atomic, and molecular species. Laser created kernels expand into a cold ambient with high velocities during its early lifetime followed by confinement of the plasma kernel and eventually collapse. However, the plasma kernels produced during laser breakdown of gases are also capable of exciting and ionizing the surrounding ambient medium. Two mechanisms can be responsible for excitation and ionization of surrounding ambient: viz. photoexcitation and ionization by intense ultraviolet emission from the sparks produced during the early times of its creation and/or heating by strong shocks generated by the kernel during its expansion into the ambient. In this study, an investigation is made on the spectral features of on- and off-axis emission features of laser-induced plasma breakdown kernels generated in atmospheric pressure conditions with an aim to elucidate the mechanisms leading to ambient excitation and emission. Pulses from an Nd:YAG laser emitting at 1064 nm with 6 ns pulse duration are used to generate plasma kernels. Laser sparks were generated in air, argon, and helium gases to provide different physical properties of expansion dynamics and plasma chemistry considering the differences in laser absorption properties, mass density and speciation. Point shadowgraphy and time-resolved imaging were used to evaluate the shock wave and spark self-emission morphology at early and late times while space and time resolved spectroscopy is used for evaluating the emission features as well as for inferring plasma fundaments at on- and off-axis. Structure and dynamics of the plasma kernel obtained using imaging techniques are also compared to numerical simulations using computational fluid dynamics code. The emission from the kernel showed that spectral features from ions, atoms and molecules are separated in

  17. Unresolved spectral structures emitted from heavy atom plasmas produced by short pulse laser

    International Nuclear Information System (INIS)

    Fraenkel, M.; Zigler, A.

    1999-01-01

    Spectra of rare earth elements emitted from ultra short pulse laser produced plasma were recorded using simultaneously high and low resolution, spectrometers. A study of the broad band emission of the Δn = 1 transitions in highly ionized Ba and Sm plasma showed that this band is completely unresolved. The spectra were analyzed using the LTE based on super-transition array (STA) model. The theory reconstructs the entire Ba spectrum using a single temperature and density, whereas for Sm the discrepancies between the theory and experiment are not reconcilable. The agreement in the Ba case is attributed to the fact that BaF 2 target is transparent to the laser's prepulse effects, producing a homogeneous dense plasma, whereas for Sm the dilute plasma created by the prepulse is far from LTE. The obtained results posses a significant implication to the applicability of the STA model, in particular for calculations of opacities and conversion of laser light to X-rays. (orig.)

  18. Effects of a static inhomogeneous magnetic field acting on a laser-produced carbon plasma plume

    Directory of Open Access Journals (Sweden)

    M. Favre

    2017-08-01

    Full Text Available We present time- and space-resolved observations of the dynamics of a laser-produced carbon plasma, propagating in a sub-Tesla inhomogeneous magnetic field, with both, axial and radial field gradients. An Nd:YAG laser pulse, 340 mJ, 3.5 ns, at 1.06 μm, with a fluence of 7 J/cm2, is used to generate the plasma from a solid graphite target, in vacuum. The magnetic field is produced using two coaxial sets of two NeFeB ring magnets, parallel to the laser target surface. The diagnostics include plasma imaging with 50 ns time resolution, spatially resolved optical emission spectroscopy and Faraday cup. Based on our observations, evidence of radial and axial plasma confinement due to magnetic field gradients is presented. Formation of C2 molecules, previously observed in the presence of a low pressure neutral gas background, and enhanced on-axis ion flux, are ascribed to finite Larmor radius effects and reduced radial transport due to the presence of the magnetic field.

  19. Unresolved spectral structures emitted from heavy atom plasmas produced by short pulse laser

    Energy Technology Data Exchange (ETDEWEB)

    Fraenkel, M.; Zigler, A. [Hebrew Univ., Jerusalem (Israel). Racah Inst. of Physics; Bar-Shalom, A.; Oreg, J. [Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev; Faenov, A.Ya.; Pikuz, T.A. [Multicharged Ions Spectra Data Center of VNIIFTRI, Russian Committee of Standards Moscow region (Russian Federation)

    1999-09-01

    Spectra of rare earth elements emitted from ultra short pulse laser produced plasma were recorded using simultaneously high and low resolution, spectrometers. A study of the broad band emission of the {delta}n = 1 transitions in highly ionized Ba and Sm plasma showed that this band is completely unresolved. The spectra were analyzed using the LTE based on super-transition array (STA) model. The theory reconstructs the entire Ba spectrum using a single temperature and density, whereas for Sm the discrepancies between the theory and experiment are not reconcilable. The agreement in the Ba case is attributed to the fact that BaF{sub 2} target is transparent to the laser's prepulse effects, producing a homogeneous dense plasma, whereas for Sm the dilute plasma created by the prepulse is far from LTE. The obtained results posses a significant implication to the applicability of the STA model, in particular for calculations of opacities and conversion of laser light to X-rays. (orig.)

  20. Ion Flux Measurements in Electron Beam Produced Plasmas in Atomic and Molecular Gases

    Science.gov (United States)

    Walton, S. G.; Leonhardt, D.; Blackwell, D. D.; Murphy, D. P.; Fernsler, R. F.; Meger, R. A.

    2001-10-01

    In this presentation, mass- and time-resolved measurements of ion fluxes sampled from pulsed, electron beam-generated plasmas will be discussed. Previous works have shown that energetic electron beams are efficient at producing high-density plasmas (10^10-10^12 cm-3) with low electron temperatures (Te < 1.0 eV) over the volume of the beam. Outside the beam, the plasma density and electron temperature vary due, in part, to ion-neutral and electron-ion interactions. In molecular gases, electron-ion recombination plays a significant role while in atomic gases, ion-neutral interactions are important. These interactions also determine the temporal variations in the electron temperature and plasma density when the electron beam is pulsed. Temporally resolved ion flux and energy distributions at a grounded electrode surface located adjacent to pulsed plasmas in pure Ar, N_2, O_2, and their mixtures are discussed. Measurements are presented as a function of operating pressure, mixture ratio, and electron beam-electrode separation. The differences in the results for atomic and molecular gases will also be discussed and related to their respective gas-phase kinetics.

  1. Some parameters of uranium hexafluoride plasma produced by products of nuclear reaction

    International Nuclear Information System (INIS)

    Batyrbekov, G.A.; Belyakova, Eh.A.

    1996-01-01

    The probe experimental results of investigation of uranium hexafluoride plasma produced in the centre of nuclear reactor core were demonstrated. Study of uranium hexafluoride plasma is continued by the following reasons: a possibility of U F 6 utilization as nuclear fuel, the utilization of U F 6 as volume source o ionization, search of active laser media compatible with U F 6 that is complicated by lack of constant rates data for most of plasma-chemical reactions with U F 6 and his dissociation products. Cylindrical probe volt-ampere characteristics (VAC) measured in U F 6 plasma at pressure 20 Torr and different thermal neutron fluxes and have following features: -firstly, it is possible to choose a linear part in the field of small positive potentials of probe (0-1) V; - secondary, ion branches of VAC have typical break which current of satiation corresponds to; -thirdly, probe VAC measured at small values of thermal neutron flux density are symmetrical. Diagnostics approaches were used for interpretation VAC of probe. The values of satiation current and linear part of electron branch were calculated, and such plasma parameters as conductivity, diffusion coefficient values of positive and negative ions were determined. The resonance recharge cross section was estimated on diffusion coefficient value

  2. Spectral investigation of highly ionized bismuth plasmas produced by subnanosecond Nd:YAG laser pulses

    Science.gov (United States)

    Wu, Tao; Higashiguchi, Takeshi; Li, Bowen; Arai, Goki; Hara, Hiroyuki; Kondo, Yoshiki; Miyazaki, Takanori; Dinh, Thanh-Hung; Dunne, Padraig; O'Reilly, Fergal; Sokell, Emma; O'Sullivan, Gerry

    2016-02-01

    The unresolved transition arrays (UTAs) emitted from laser produced bismuth (Bi) plasma sources show potential for single-shot live cell imaging. We have measured extreme ultraviolet spectra from bismuth laser produced plasmas in the 1-7 nm region using a λ = 1064 nm Nd:YAG laser with a pulse duration of 150 ps. Comparison of spectra obtained under different laser power densities with calculations using the Hartree-Fock with configuration interaction Cowan suite of codes and the UTA formalism, as well as consideration of previous predictions of isoelectronic trends, are employed to identify lines and a number of new features in spectra from Bi XXIII to Bi XLVII. The results show that Δn = 0, n = 4-4 emission from highly charged ions merges to form intense UTAs in the 4 nm region and Δn = 1, n = 4-5 resonance transitions UTAs dominate the 1-3 nm region of the Bi spectrum.

  3. Spectral investigation of highly ionized bismuth plasmas produced by subnanosecond Nd:YAG laser pulses

    International Nuclear Information System (INIS)

    Wu, Tao; Higashiguchi, Takeshi; Arai, Goki; Hara, Hiroyuki; Kondo, Yoshiki; Miyazaki, Takanori; Dinh, Thanh-Hung; Li, Bowen; Dunne, Padraig; O’Reilly, Fergal; Sokell, Emma; O’Sullivan, Gerry

    2016-01-01

    The unresolved transition arrays (UTAs) emitted from laser produced bismuth (Bi) plasma sources show potential for single-shot live cell imaging. We have measured extreme ultraviolet spectra from bismuth laser produced plasmas in the 1–7 nm region using a λ = 1064 nm Nd:YAG laser with a pulse duration of 150 ps. Comparison of spectra obtained under different laser power densities with calculations using the Hartree–Fock with configuration interaction Cowan suite of codes and the UTA formalism, as well as consideration of previous predictions of isoelectronic trends, are employed to identify lines and a number of new features in spectra from Bi XXIII to Bi XLVII. The results show that Δn = 0, n = 4–4 emission from highly charged ions merges to form intense UTAs in the 4 nm region and Δn = 1, n = 4–5 resonance transitions UTAs dominate the 1–3 nm region of the Bi spectrum. (paper)

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

    Science.gov (United States)

    Ciardi, A; Vinci, T; Fuchs, J; Albertazzi, B; Riconda, C; Pépin, 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.

  5. Characteristics of plasma in uranium atomic beam produced by electron-beam heating

    International Nuclear Information System (INIS)

    Ohba, Hironori; Shibata, Takemasa

    2000-08-01

    The electron temperature of plasma and the ion flux ratio in the uranium atomic beam produced by electron-beam heating were characterized with Langmuir probes. The electron temperature was 0.13 eV, which was lower than the evaporation surface temperature. The ion flux ratio to atomic beam flux was more than 3% at higher evaporation rates. The ion flux ratio has increased with decreasing acceleration energy of the electron-beam under constant electron-beam power. This is because of an increase of electron-beam current and a large ionization cross-section of uranium by electron-impact. It was confined that the plasma is produced by electron-impact ionization of the evaporated atoms at the evaporation source. (author)

  6. Physical principles of the surface-plasma method of producing beams of negative ions

    International Nuclear Information System (INIS)

    Bel'chenko, Yu.I.; Dimov, G.I.; Dudnikov, V.G.

    A study is made of the processes used to produce intensive beams of negative ions from surface-plasma sources (SPS). The concepts now being formulated concerning the formation of negative ions upon interaction of bombarding particles with the surface of a solid are analyzed. The peculiarities of the realization of optimal conditions for the production of beams of negative ions in SPS of various designs are discussed

  7. Stimulated Brillouin backscattering losses in weakly inhomogeneous laser-produced plasmas

    International Nuclear Information System (INIS)

    Eidmann, K.; Brederlow, G.; Brodmann, R.; Petsch, R.; Sigel, R.; Tsarkiris, G.; Volk, R.; Witkowski, S.

    1979-02-01

    Studies of the reflection from a plane solid target plasma produced with a 1TW iodine laser (lambda = 1.3μm) at pulse durations of 300 ps are presented. The specularly reflected and the backscattered light was observed separately at different angles of incidence, intensities and spot sizes (up to 400 μm). Stimulated Brillouin scattering was identified as the main mechanism for backscattering with saturation at 20 - 30% reflection. (orig.) [de

  8. Ion emission from laser-produced plasmas with two electron temperatures

    International Nuclear Information System (INIS)

    Wickens, L.M.; Allen, J.E.; Rumsby, P.T.

    1978-01-01

    An analytic theory for the expansion of a laser-produced plasma with two electron temperatures is presented. It is shown that from the ion-emission velocity spectrum such relevant parameters as the hot- to -cold-electron density ratio, the absolute hot- and cold-electron temperatures, and a sensitive measure of hot- and cold-electron temperature ratio can be deduced. A comparison with experimental results is presented

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

    International Nuclear Information System (INIS)

    Marcus, Gilad; Louzon, Einat; Henis, Zohar; Maman, Shlomo; Mandelbaum, Pinchas

    2007-01-01

    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. Recombining processes in a cooling plasma by mixing of initially heated gas

    International Nuclear Information System (INIS)

    Furukane, Utaro; Sato, Kuninori; Takiyama, Ken; Oda, Toshiatsu.

    1992-03-01

    A numerical investigation of recombining process in a high temperature plasma in a quasi-steady state is made in a gas contact cooling, in which the initial temperature effect of contact gas heated up by the hot plasma is considered as well as the gas cooling due to the surrounding neutral particles freely coming into the plasma. The calculation has shown that the electron temperature relaxes in accord with experimental results and that the occurrence of recombining region and the inverted populations almost agree with the experimental ones. (author)

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

    International Nuclear Information System (INIS)

    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 16 cm -3 and an ion temperature T/sub i/ = 15 eV at midcoil and by N/sub i/ = 0.5 x 10 16 cm -3 and T/sub i/ = 6 eV at a position 2.5 cm beyond the end of the theta coil

  12. Selection of daunorubicin-producing strain S. Coeruleorubidus by plasma radiation technology

    International Nuclear Information System (INIS)

    Jiang Shichun; Wu Jianping; Bai Hua

    2001-01-01

    The authors reported the results of mutagenesis by nitrogen plasma radiation with energy from 65 to 80 keV and dose from 9.6 x 10 9 to 1.5 x 10 11 /cm 2 in antineoplastic antibiotics daunorubicin-producing S. Coeruleorubidus. The relationship between death rate and radiation dose was formulated by computer and the formula. It was fit to a biological single-hit curve. The obtained high-producing mutagenic strain 137 was tested for its production property. The result showed that it could increase the daunorubicin potency by 25.8% in productive tanks of fermentation

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

    Science.gov (United States)

    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 μm 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. Characterization of a dielectric barrier discharge in contact with liquid and producing a plasma activated water

    Science.gov (United States)

    Neretti, G.; Taglioli, M.; Colonna, G.; Borghi, C. A.

    2017-01-01

    limited deviations from Maxwellian distribution were observed, calculated electron temperature is in good agreement with the one measured by means of spectroscopic diagnostics. Computed temporal evolution of the energy delivered to the discharge is comparable with the one obtained from electrical measurements. The electrical discharges supplied by both voltage waveforms produce plasma activated water with negligible thermal effects and pH variations.

  15. Hot electron effects on the satellite spectrum of laser-produced plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Abdallah, J. [Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM (United States); Faenov, A.Y.; Pikuz, T.A. [MISDC, NPO ' VNIIFTRI' , Mendeleevo, Moscow Region, 141570 (Russian Federation); Wilke, M.D.; Kyrala, G.A.; Clark, R.E.H. [Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM (United States)

    1999-05-01

    In laser-produced plasmas, the interaction of the intense laser light with plasma electrons can produce high-energy superthermal electrons with energies in the keV range. These hot electrons can influence the level populations which determine spectral line structure. In the present paper, the effect of hot electrons on the X-ray satellite spectrum of laser-produced plasmas is studied. Calculated spectra are compared with experimental observations. Magnesium targets irradiated by three different types of laser pulses are considered. These include, a high-intensity 600 fs Nd-glass laser, a 1 ns Nd-glass laser, and a 2ns CO{sub 2} laser. The Nd-glass laser experiments were conducted recently at the Los Alamos Trident Facility and the CO{sub 2} data were recorded by MISDC. High-resolution spectra were measured near the He-like resonance line of magnesium. The calculations employ an electron energy distribution which includes a thermal and a hot electron component, as part of a detailed collisional-radiative model. Plasma parameters including electron temperature, density, and hot electron fraction are estimated by choosing best fits to the experimental measurements. The calculations show that hot electrons can cause several anomalous effects. The Li-like jkl, abcd, and qr satellites can show intensities which are generally attributed to electron densities in excess of 10{sup 23} cm{sup -3}. In addition, the relative amplitude of the intercombination line can be unusually large even at high electron densities due to enhanced collisional excitation of the 1s2p{sup 3}P state by hot electrons. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  16. Time-resolved spectroscopy of nonequilibrium ionization in laser-produced plasmas

    International Nuclear Information System (INIS)

    Marjoribanks, R.S.

    1988-01-01

    The highly transient ionization characteristic of laser-produced plasmas at high energy densities has been investigated experimentally, using x-ray spectroscopy with time resolution of less than 20 ps. Spectroscopic diagnostics of plasma density and temperature were used, including line ratios, line profile broadening and continuum emission, to characterize the plasma conditions without relying immediately on ionization modeling. The experimentally measured plasma parameters were used as independent variables, driving an ionization code, as a test of ionization modeling, divorced from hydrodynamic calculations. Several state-of-the-art streak spectrographs, each recording a fiducial of the laser peak along with the time-resolved spectrum, characterized the laser heating of thin signature layers of different atomic numbers imbedded in plastic targets. A novel design of crystal spectrograph, with a conically curved crystal, was developed. Coupled with a streak camera, it provided high resolution (λ/ΔΛ > 1000) and a collection efficiency roughly 20-50 times that of planar crystal spectrographs, affording improved spectra for quantitative reduction and greater sensitivity for the diagnosis of weak emitters. Experimental results were compared to hydrocode and ionization code simulations, with poor agreement. The conclusions question the appropriateness of describing electron velocity distributions by a temperature parameter during the time of laser illumination and emphasis the importance of characterizing the distribution more generally

  17. Experimental investigation of linear mode conversion in laser-produced plasmas

    International Nuclear Information System (INIS)

    Maaswinkel, A.G.M.

    1980-12-01

    In this work absorption mechanisms are investigated in hot dense plasmas produced by intense laser irradiation of planar targets. Central in this investigation stands the absorption by linear mode conversion; this process occurs in inhomogeneous plasmas if the electric field vector of the incident EM-wave has a component parallel to the density gradient; this causes electrostatic oscillations at the critical density (where ωsub(p)sub(e) = ω). In addition, absorption of the laser light by inverse bremsstrahlung is investigated. The absorption is determined by the reflection of the laser light from the plasma. To this aim optical diagnostics are used. The reflection into 4π sr is measured with an Ulbricht sphere, also the reflection in specular (geometric) direction is recorded. The absorption mechanisms have been isolated by variation of the polarization of the beam and the angle of incidence to the target. An essential part of the work has been the frequency up-conversion of the laser beam by nonlinear crystals; in this way the wavelength-dependence of the absorption in the plasma has been investigated at wavelengths 1.06 μm, 0.53 μm and 0.26 μm; the pulse duration in the experiments was 30 ps, the maximum irradiation on target was 10 14 W/cm 2 . (orig./HT)

  18. Air core poloidal magnetic field system for a toroidal plasma producing device

    International Nuclear Information System (INIS)

    Marcus, F.B.

    1978-01-01

    A poloidal magnetics system for a plasma producing device of toroidal configuration is provided that reduces both the total volt-seconds requirement and the magnitude of the field change at the toroidal field coils. The system utilizes an air core transformer wound between the toroidal field (TF) coils and the major axis outside the TF coils. Electric current in the primary windings of this transformer is distributed and the magnetic flux returned by air core windings wrapped outside the toroidal field coils. A shield winding that is closely coupled to the plasma carries a current equal and opposite to the plasma current. This winding provides the shielding function and in addition serves in a fashion similar to a driven conducting shell to provide the equilibrium vertical field for the plasma. The shield winding is in series with a power supply and a decoupling coil located outside the TF coil at the primary winding locations. The present invention requires much less energy than the usual air core transformer and is capable of substantially shielding the toroidal field coils from poloidal field flux

  19. The CRINE initiative -- Producing the engineering tools (functional specifications and common working practices)

    International Nuclear Information System (INIS)

    Tuft, V.

    1995-01-01

    Alongside culture change, CRINE's other challenge is producing the right tools for the North Sea industry to change its traditional method of operation. CRINE, an acronym for Cost Reduction Initiative for the New Era, is an industry-wide program now underway in the UK Continental Shelf whose main objective is to achieve thirty percent or more savings in capital costs and to half operating costs over the next few years. These tools cover functional specifications, common working practices and quality. Turning these tools into deliverables, and on time, was a mixture of painstaking work and willingness by people to adapt to the needs of the task

  20. Theory of electron degradation and yields of initial molecular species produced by ionizing radiation

    International Nuclear Information System (INIS)

    Inokuti, M.; Dillon, M.A.; Kimura, M.

    1987-01-01

    Ionizing radiations generate in matter a large number of energetic electrons, which in turn collide with molecules in matter, produce ions and excited states, and thereby degrade in energy. The description of the consequences of many collision processes to the electrons and to matter is the goal of the electron degradation theory. They summarize the current understanding of this topic, which is important as a basis of radiation chemistry and biology. In addition, they present an initial report of their new work, namely, a generalization of the Spencer-Fano theory to time-dependent cases

  1. Initial measurement of assets produced in Bulgarian companies – current state and ways for improvement

    Directory of Open Access Journals (Sweden)

    Mincho Minev

    2017-10-01

    Full Text Available The initial evaluation of the production is one of the most complex tasks that accounting specialists face in their practice. The quality of the accounting information provided to the various internal and external users depends to a great extent on the way in which this task is resolved. In this article, using the results of an undertaken research, the practice of leading Bulgarian companies will be analyzed with regard to the costing of their production. The main purpose is to make recommendations for optimizing the process of costing in Bulgarian companies and to increase the quality of the accounting information produced as a result of this process.

  2. A review on microbiological decontamination of fresh produce with nonthermal plasma.

    Science.gov (United States)

    Pignata, C; D'Angelo, D; Fea, E; Gilli, G

    2017-06-01

    Food safety is a critical public health issue for consumers and the food industry because microbiological contamination of food causes considerable social and economic burdens on health care. Most foodborne illness comes from animal production, but as of the mid-1990s in the United States and more recently in the European Union, the contribution of fresh produce to foodborne outbreaks has rapidly increased. Recent studies have suggested that sterilization with nonthermal plasma could be a viable alternative to the traditional methods for the decontamination of heat-sensitive materials or food because this technique proves capable of eliminating micro-organisms on surfaces without altering the substrate. In the last 10 years, researchers have used nonthermal plasma in a variety of food inoculated with many bacterial species. All of these experiments were conducted exclusively in a laboratory and, to our knowledge, this technique has not been used in an industrial setting. Thus, the purpose of this review is to understand whether this technology could be used at the industrial level. The latest researches using nonthermal plasma on fresh produce were analysed. These evaluations have focused on the log reduction of micro-organisms and the treatment time. © 2017 The Society for Applied Microbiology.

  3. Target surface structure effects on x-ray generation from laser produced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Nishikawa, Tadashi; Nakano, Hidetoshi; Uesugi, Naoshi [NTT Basic Research Laboratories, Atsugi, Kanagawa (Japan)

    2000-03-01

    We demonstrated two different methods to increase the x-ray conversion efficiency of laser-produced plasma by modifying the target surface structure. One way is making a rectangular groove on a target surface and confining a laser-produced plasma in it. By the plasma collision process, a time and wavelength (4-10 nm) integrated soft x-ray fluence enhancement of 35 times was obtained at a groove width of 20 {mu}m and a groove depth of 100 {mu}m on a Nd-doped glass target. The other way is making an array of nanoholes on an alumina target and increasing the laser interaction depth with it. The x-ray fluence enhancement increases as the ionization level of Al becomes higher and the x-ray wavelength becomes shorter. Over 50-fold enhancement was obtained at a soft x-ray wavelength around 6 nm, which corresponds to the emission from Al{sup 8+,9+} ions. (author)

  4. Target surface structure effects on x-ray generation from laser produced plasma

    International Nuclear Information System (INIS)

    Nishikawa, Tadashi; Nakano, Hidetoshi; Uesugi, Naoshi

    2000-01-01

    We demonstrated two different methods to increase the x-ray conversion efficiency of laser-produced plasma by modifying the target surface structure. One way is making a rectangular groove on a target surface and confining a laser-produced plasma in it. By the plasma collision process, a time and wavelength (4-10 nm) integrated soft x-ray fluence enhancement of 35 times was obtained at a groove width of 20 μm and a groove depth of 100 μm on a Nd-doped glass target. The other way is making an array of nanoholes on an alumina target and increasing the laser interaction depth with it. The x-ray fluence enhancement increases as the ionization level of Al becomes higher and the x-ray wavelength becomes shorter. Over 50-fold enhancement was obtained at a soft x-ray wavelength around 6 nm, which corresponds to the emission from Al 8+,9+ ions. (author)

  5. Characteristics of laser produced plasmas of hafnium and tantalum in the 1-7 nm region

    Science.gov (United States)

    Li, Bowen; Otsuka, Takamitsu; Sokell, Emma; Dunne, Padraig; O'Sullivan, Gerry; Hara, Hiroyuki; Arai, Goki; Tamura, Toshiki; Ono, Yuichi; Dinh, Thanh-Hung; Higashiguchi, Takeshi

    2017-11-01

    Soft X-ray (SXR) spectra from hafnium and tantalum laser produced plasmas were recorded in the 1-7 nm region using two Nd:YAG lasers with pulse lengths of 170 ps and 10 ns, respectively, operating at a range of power densities. The maximum focused peak power density was 2. 3 × 1014 W cm-2 for 170 ps pulses and 1. 8 × 1012 W cm-2 for 10 ns pulses, respectively. Two intense quasicontinuous intensity bands resulting from n = 4 - n = 4 and n = 4 - n = 5 unresolved transition arrays (UTAs) dominate both sets of experimental spectra. Comparison with calculations performed with the Cowan suite of atomic structure codes as well as consideration of previous experimental and theoretical results aided identification of the most prominent features in the spectra. For the 10 ns spectrum, the highest ion stage that could be identified from the n = 4 - n = 5 arrays were lower than silver-like Hf25+ and Ta26+ (which has a 4 d 104 f ground configuration) indicating that the plasma temperature attained was too low to produce ions with an outermost 4 d subshell, while for the 170 ps plasmas the presence of significantly higher stages was deduced and lines due to 4 d-5 p transitions were clearly evident. Furthermore, we show an enhancement of emission from tantalum using dual laser irradiation, and the effect of pre-pulse durations and delay times between two pulses are demonstrated.

  6. Light scattering measurements with Titan's aerosols analogues produced by dusty plasma

    Science.gov (United States)

    Hadamcik, E.; Renard, J.-B.; Szopa, C.; Cernogora, G.; Levasseur-Regourd, A. C.

    The Titan s atmosphere contains solid aerosols produced by the photochemistry of nitrogen and methane These aerosols are at the origin of the characteristic brown yellow colour of Titan During the descent of the Huygens probe the 14 th January 2005 optical measurements of the Titan s haze and Titan s surface have been done In order to explain the obtained results laboratory simulations are necessary We produce analogues of the Titan s aerosols in a RF capacitively coupled low-pressure plasma in a N 2 --CH 4 mixture representative of the Titan s atmosphere Szopa et al 2006 Szopa et al this conference The morphology of the produced solid aerosols is observed by SEM analyses They are quasi spherical and their mean size is function of the plasma conditions Moreover their colour changes from yellow to brown as a function of CH 4 ratio in the plasma In order to have information on the optical properties of the produced aerosols measurements have been performed with the PROGRA2 experiment Renard et al 2002 The PROGRA2 experiment measures the phase dependence of the linear polarization of the light scattered by dust particles for two wavelengths 543 5 nm and 632 8 nm The particles are lifted either in microgravity in the CNES ESA dedicated airplane or by an air-draught in ground-based conditions The aim of this work is to build a database for further modelling of the optical properties of Titan s in connection with the Huygens data These particles have also an astrophysical interest as organic compounds Hadamcik et

  7. Diffraction, self-focusing, and the geometrical optics limit in laser produced plasmas

    International Nuclear Information System (INIS)

    Marchand, R.; Rankin, R.; Capjack, C.E.; Birnboim, A.

    1987-01-01

    The effect of diffraction on the self-modulation of an intense laser beam in an initially uniform hydrogen plasma is investigated. A formalism is used in which the diffraction term in the paraxial wave equation can be arbitrarily reduced by the use of a weight factor iota. In the limit where iota approaches zero, it is shown that the paraxial wave equation correctly reduces to the geometrical optics limit and that the problem then becomes formally equivalent to solving the ray-tracing equations. When iota = 1, the paraxial wave equation takes its usual form and diffraction is fully accounted for. This formalism is applied to the simulation of self-modulation of an intense laser beam in a hydrogen plasma, for which diffraction is shown to be significant

  8. Vacuum laser-initiated plasma shutters for retropulse isolation in Antares

    International Nuclear Information System (INIS)

    Sheheen, T.W.; Czuchlewski, S.J.; Hyde, J.; Ainsworth, R.L.

    1983-03-01

    We have demonstrated that sintered LiF spatial filters may be used in a 10 -6 -torr vacuum environment as laser-initiated plasma shutters for retropulse isolation in the Antares high-energy laser fusion system. In our experiments, a 1.1-ns pulsed CO 2 laser, at a 10-μm wavelength and an energy of up to 3.0 J, was used for plasma initiation; a chopped probe laser tuned to a 9l6-μm wavelength was used in determining the blocking time of the plasma. We measured the 10.6- and 9.6-μm beam transmissions as a function of fluence on the aperture edge. For an 800-μm-diam aperture and a 1.2-mm-diam Gaussian beam determined at the 1/e 2 intensity points, we observed blocking times in excess of 1.0 μs

  9. Application of laser-produced-plasmas to determination of carbon content in steel

    International Nuclear Information System (INIS)

    Ortiz, M.; Aragon, C.; Aguilera, J.A.; Campos, J.

    1994-01-01

    This paper describes an analytical method to determine carbon content in solid and molten steel. It is based on the study of the emission spectrum from a Nd-YAG laser produced plasma. The light emitted from the plasma is focused to the entrance slit of a spectrometer and detected by an OMA III system. For every laser pulse an spectral range of 100 A are recorded. With the use of time-resolved spectroscopy a precision of 1.6% and a detection limit of 65 ppm of carbon content in steel have been obtained. These values are similar to those of other accurate conventional techniques but using optics fiber and laser excitation it is possible to made sample calibrations in hostile environments. Also, as the analysis are made in real time changes in sample composition can be measured without stopping production processes. (Author) 26 refs

  10. Laser-produced plasma-extreme ultraviolet light source for next generation lithography

    International Nuclear Information System (INIS)

    Nishihara, Katsunobu; Nishimura, Hiroaki; Gamada, Kouhei; Murakami, Masakatsu; Mochizuki, Takayasu; Sasaki, Akira; Sunahara, Atsushi

    2005-01-01

    Extreme ultraviolet (EUV) lithography is the most promising candidate for the next generation lithography for the 45 nm technology node and below. EUV light sources under consideration use 13.5 nm radiations from multicharged xenon, tin and lithium ions, because Mo/Si multiplayer mirrors have high reflectivity at this wavelength. A review of laser-produced plasma (LPP) EUV light sources is presented with a focus on theoretical and experimental studies under the auspices of the Leading Project promoted by MEXT. We discuss three theoretical topics: atomic processes in the LPP-EUV light source, conversion efficiency from laser light to EUV light at 13.5 nm wave-length with 2% bound width, and fast ion spectra. The properties of EUV emission from tin and xenon plasmas are also shown based on experimental results. (author)

  11. Spectroscopic study of emission coal mineral plasma produced by laser ablation

    International Nuclear Information System (INIS)

    Vera, L P; Pérez, J A; Riascos, H

    2014-01-01

    Spectroscopic analysis of plasma produced by laser ablation of coal samples using 1064 nm radiation pulses from a Q-switched Nd:YAG on different target under air ambient, was performed. The emission of molecular band systems such as C 2 Swan System (d 3 Π g →a 3 Π u ), the First Negative System N 2 (Band head at 501,53 nm) and emission lines of the C I, C II, were investigated using the optical emission spectroscopy technique. The C 2 molecular spectra (Swan band) were analyzed to determine vibrational temperature (0,62 eV); the density and electron temperature of the plasma have been evaluated using Stark broadening and the intensity of the nitrogen emission lines N II, the found values of 1,2 eV and 2,2 x10 18 cm −3 respectively.

  12. Relativistic electron drift in overdense plasma produced by a superintense femtosecond laser pulse

    International Nuclear Information System (INIS)

    Rastunkov, V.S.; Krainov, V.P.

    2004-01-01

    The general peculiarities of electron motion in the skin layer at the irradiation of overdense plasma by a superintense linearly polarized laser pulse of femtosecond duration are considered. The quiver electron energy is assumed to be a relativistic quantity. Relativistic electron drift along the propagation of laser radiation produced by a magnetic part of a laser field remains after the end of the laser pulse, unlike the relativistic drift of a free electron in underdense plasma. As a result, the penetration depth is much larger than the classical skin depth. The conclusion has been made that the drift velocity is a nonrelativistic quantity even at the peak laser intensity of 10 21 W/cm 2 . The time at which an electron penetrates into field-free matter from the skin layer is much less than the pulse duration

  13. X-ray spectral line shapes for the excimer-laser-produced high density plasma diagnostics

    International Nuclear Information System (INIS)

    Magunov, A.; Faenov, A.; Skobelev, I.; Pikuz, T.; Batani, D.; Milani, M.; Conti, A.; Masini, A.; Costato, M.; Pozzi, A.; Turcu, E.; Allot, R.; Lisi, N.; Koenig, M.; Benuzzi, A.; Flora, F.; Letardi, T.; Palladino, L.; Reale, A.

    1997-01-01

    The time and space-integrated emission spectra measurements have been performed in plasma produced by 308 nm wavelength XeCl laser radiation (I L =(4-10)·10 12 W/cm 2 , τ=10 ns) and by 248 nm wavelength KrF laser pulse train radiation (I L =5·10 15 W/cm 2 , τ=7 ps, 16 pulses in train) on CF n plane target. The lines' shapes and intensities modeling of Lyman series and He-like ion resonance series of fluorine up to n=7 by fitting experimental data shows the considerable difference of plasma formation features for these two sets of the laser pulse parameters

  14. On the line broadening and shifts of Al laser produced plasma

    International Nuclear Information System (INIS)

    She Yongbo; Chen Yunfang; Zhao Ruwen; Zhang Xiulan; Pan Guangyan

    1985-01-01

    We have studied the spatially resolved spectra of Al laser produced plasma. In the range from 2300-4000A about thirty emission lines have been observed belonging to the neutral, singly and doubly ionized Al species. Their line widths and shifts vary with the distance between the plasma and the Al-target surface. Five lines from differently ionized species have been examined with the aid of the theoretical formula given by Griem, and the distribution of electron density near the target has been determined semi-empirically. We found that the line broadening of the different species coincided well with each other, and could be used as a measure of electron density in the range from 1.10 17 to 5.10 18 cm -3 . But the coincidence between the line shifts seems not so good, especially for the lines of 3587 A of Al II and 3610 A of Al III. It remains to be further investigated

  15. Time-resolved probing of electron thermal conduction in femtosecond-laser-pulse-produced plasmas

    International Nuclear Information System (INIS)

    Vue, B.T.V.

    1993-06-01

    We present time-resolved measurements of reflectivity, transmissivity and frequency shifts of probe light interacting with the rear of a disk-like plasma produced by irradiation of a transparent solid target with 0.1ps FWHM laser pulses at peak intensity 5 x 10 l4 W/CM 2 . Experimental results show a large increase in reflection, revealing rapid formation of a steep gradient and overdense surface plasma layer during the first picosecond after irradiation. Frequency shifts due to a moving ionization created by thermal conduction into the solid target are recorded. Calculations using a nonlinear thermal heat wave model show good agreement with the measured frequency shifts, further confining the strong thermal transport effect

  16. Application of laser-produced-plasmas to determination of carbon content in steel

    International Nuclear Information System (INIS)

    Ortiz, M.; Aragon, C.; Aguilera, J. A.; Campos, J.

    1994-01-01

    This paper describes an analytical method to determine carbon content in solid and molten steel. It is based on the study of the emission spectrum from a Nd-YAG laser produced plasma. The light emitted from the plasma is focused to the entrance slit of a spectrometer and detected by an OMA III system. For every laser pulse an spectral range of 100 A are recorded. With the use of time-resolved spectroscopy a precision of 1.6 % and a detection limit of 65 ppm of carbon content in steel have been obtained. These values are similar to those of other accurate conventional techniques but using optics fiber and laser excitation it is possible to made sample calibrations in hostile environments. Also, as the analysis are made in real time changes in sample composition can be measured without stopping production processes. (Author) 26 refs

  17. Plasma Discharge Initiation of Explosives in Rock Blasting Application: A Case Study

    International Nuclear Information System (INIS)

    Chae, Jae-Ou; Jeong, Young-Jun; Shmelev, V M; Denicaev, A A; Poutchkov, V M; Ravi, V

    2006-01-01

    A plasma discharge initiation system for the explosive volumetric combustion charge was designed, investigated and developed for practical application. Laboratory scale experiments were carried out before conducting the large scale field tests. The resultant explosions gave rise to less noise, insignificant seismic vibrations and good specific explosive consumption for rock blasting. Importantly, the technique was found to be safe and environmentally friendly

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

    International Nuclear Information System (INIS)

    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. Demonstration of Ion Kinetic Effects in Inertial Confinement Fusion Implosions and Investigation of Magnetic Reconnection Using Laser-Produced Plasmas

    Science.gov (United States)

    Rosenberg, M. J.

    2016-10-01

    Shock-driven laser inertial confinement fusion (ICF) implosions have demonstrated the presence of ion kinetic effects in ICF implosions and also have been used as a proton source to probe the strongly driven reconnection of MG magnetic fields in laser-generated plasmas. Ion kinetic effects arise during the shock-convergence phase of ICF implosions when the mean free path for ion-ion collisions (λii) approaches the size of the hot-fuel region (Rfuel) and may impact hot-spot formation and the possibility of ignition. To isolate and study ion kinetic effects, the ratio of N - K =λii /Rfuel was varied in D3He-filled, shock-driven implosions at the Omega Laser Facility and the National Ignition Facility, from hydrodynamic-like conditions (NK 0.01) to strongly kinetic conditions (NK 10). A strong trend of decreasing fusion yields relative to the predictions of hydrodynamic models is observed as NK increases from 0.1 to 10. Hydrodynamics simulations that include basic models of the kinetic effects that are likely to be present in these experiments-namely, ion diffusion and Knudsen-layer reduction of the fusion reactivity-are better able to capture the experimental results. This type of implosion has also been used as a source of monoenergetic 15-MeV protons to image magnetic fields driven to reconnect in laser-produced plasmas at conditions similar to those encountered at the Earth's magnetopause. These experiments demonstrate that for both symmetric and asymmetric magnetic-reconnection configurations, when plasma flows are much stronger than the nominal Alfvén speed, the rate of magnetic-flux annihilation is determined by the flow velocity and is largely insensitive to initial plasma conditions. This work was supported by the Department of Energy Grant Number DENA0001857.

  20. Toward 3-D E-field visualization in laser-produced plasma by polarization-spectroscopic imaging

    International Nuclear Information System (INIS)

    Kim, Yong W.

    2004-01-01

    A 3-D volume radiator such as laser-produced plasma (LPP) plumes is observed in the form of a 2-D projection of its radiative structure. The traditional approach to 3-D structure reconstruction relies on multiple projections but is not suitable as a general method for unsteady radiating objects. We have developed a general method for 3-D structure reconstruction for LPP plumes in stages of increasing complexity. We have chosen neutral gas-confined LPP plumes from an aluminum target immersed in high-density argon because the plasma experiences Rayleigh-Taylor instability. We make use of two time-resolved, mutually orthogonal side views of a LPP plume and a front-view snapshot. No symmetry assumptions are needed. Two scaling relations are invoked that connects the plasma temperature and pressure to local specific intensity at selected wavelength(s). Two mutually-orthogonal lateral luminosity views of the plume at each known distance from the target surface are compared with those computed from the trial specific intensity profiles and the scaling relations. The luminosity error signals are minimized to find the structure. The front-view snapshot is used to select the initial trial profile and as a weighting function for allocation of the error signal into corrections for specific intensities from the plasma cells along the line of sight. Full Saha equilibrium for multiple stages of ionization is treated, together with the self-absorption, in the computation of the luminosity. We show the necessary optics for determination of local electric fields through polarization-resolved imaging. (author)

  1. Plasma-Based Degradation of Mycotoxins Produced by Fusarium, Aspergillus and Alternaria Species

    Directory of Open Access Journals (Sweden)

    Lars ten Bosch

    2017-03-01

    Full Text Available The efficacy of cold atmospheric pressure plasma (CAPP with ambient air as working gas for the degradation of selected mycotoxins was studied. Deoxynivalenol, zearalenone, enniatins, fumonisin B1, and T2 toxin produced by Fusarium spp., sterigmatocystin produced by Aspergillus spp. and AAL toxin produced by Alternaria alternata were used. The kinetics of the decay of mycotoxins exposed to plasma discharge was monitored. All pure mycotoxins exposed to CAPP were degraded almost completely within 60 s. Degradation rates varied with mycotoxin structure: fumonisin B1 and structurally related AAL toxin were degraded most rapidly while sterigmatocystin exhibited the highest resistance to degradation. As compared to pure compounds, the degradation rates of mycotoxins embedded in extracts of fungal cultures on rice were reduced to a varying extent. Our results show that CAPP efficiently degrades pure mycotoxins, the degradation rates vary with mycotoxin structure, and the presence of matrix slows down yet does not prevent the degradation. CAPP appears promising for the decontamination of food commodities with mycotoxins confined to or enriched on surfaces such as cereal grains.

  2. Performance Testing of Suspension Plasma Sprayed Thermal Barrier Coatings Produced with Varied Suspension Parameters

    Directory of Open Access Journals (Sweden)

    Nicholas Curry

    2015-07-01

    Full Text Available Suspension plasma spraying has become an emerging technology for the production of thermal barrier coatings for the gas turbine industry. Presently, though commercial systems for coating production are available, coatings remain in the development stage. Suitable suspension parameters for coating production remain an outstanding question and the influence of suspension properties on the final coatings is not well known. For this study, a number of suspensions were produced with varied solid loadings, powder size distributions and solvents. Suspensions were sprayed onto superalloy substrates coated with high velocity air fuel (HVAF -sprayed bond coats. Plasma spray parameters were selected to generate columnar structures based on previous experiments and were maintained at constant to discover the influence of the suspension behavior on coating microstructures. Testing of the produced thermal barrier coating (TBC systems has included thermal cyclic fatigue testing and thermal conductivity analysis. Pore size distribution has been characterized by mercury infiltration porosimetry. Results show a strong influence of suspension viscosity and surface tension on the microstructure of the produced coatings.

  3. Supersonic propagation of ionization waves in an underdense, laser-produced plasma

    International Nuclear Information System (INIS)

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

    2005-01-01

    A laser-driven supersonic ionization wave propagating through a millimeter-scale plasma of subcritical density up to 2-3 keV electron temperatures was observed. Propagation velocities initially ten 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 two-dimensional radiation-hydrodynamics code. The comparison to the modeling suggests that nonlocal heat transport effects may contribute to the attenuation of the heat-wave propagation

  4. Proton radiography of dynamic electric and magnetic fields in laser-produced high-energy-density plasmas

    International Nuclear Information System (INIS)

    Li, C. K.; Seguin, F. H.; Frenje, J. A.; Manuel, M.; Casey, D.; Sinenian, N.; Petrasso, R. D.; Amendt, P. A.; Landen, O. L.; Rygg, J. R.; Town, R. P. J.; Betti, R.; Meyerhofer, D. D.; Delettrez, J.; Knauer, J. P.; Marshall, F.; Sangster, T. C.; Smalyuk, V. A.; Soures, J. M.; Shvarts, D.

    2009-01-01

    Time-gated, monoenergetic-proton radiography provides unique measurements of the electric (E) and magnetic (B) fields produced in laser-foil interactions and during the implosion of inertial-confinement-fusion capsules. These experiments resulted in the first observations of several new and important features: (1) observations of the generation, decay dynamics, and instabilities of megagauss B fields in laser-driven planar plastic foils, (2) the observation of radial E fields inside an imploding capsule, which are initially directed inward, reverse direction during deceleration, and are likely related to the evolution of the electron pressure gradient, and (3) the observation of many radial filaments with complex electromagnetic field striations in the expanding coronal plasmas surrounding the capsule. The physics behind and implications of such observed fields are discussed.

  5. A physical mechanism producing suprathermal populations and initiating substorms in the Earth's magnetotail

    Directory of Open Access Journals (Sweden)

    D. V. Sarafopoulos

    2008-06-01

    Full Text Available We suggest a candidate physical mechanism, combining there dimensional structure and temporal development, which is potentially able to produce suprathermal populations and cross-tail current disruptions in the Earth's plasma sheet. At the core of the proposed process is the "akis" structure; in a thin current sheet (TCS the stretched (tail-like magnetic field lines locally terminate into a sharp tip around the tail midplane. At this sharp tip of the TCS, ions become non-adiabatic, while a percentage of electrons are accumulated and trapped: The strong and transient electrostatic electric fields established along the magnetic field lines produce suprathermal populations. In parallel, the tip structure is associated with field aligned and mutually attracted parallel filamentary currents which progressively become more intense and inevitably the structure collapses, and so does the local TCS. The mechanism is observationally based on elementary, almost autonomous and spatiotemporal entities that correspond each to a local thinning/dipolarization pair having duration of ~1 min. Energetic proton and electron populations do not occur simultaneously, and we infer that they are separately accelerated at local thinnings and dipolarizations, respectively. In one example energetic particles are accelerated without any dB/dt variation and before the substorm expansion phase onset. A particular effort is undertaken demonstrating that the proposed acceleration mechanism may explain the plasma sheet ratio Ti/Te≈7. All our inferences are checked by the highest resolution datasets obtained by the Geotail Energetic Particles and Ion Composition (EPIC instrument. The energetic particles are used as the best diagnostics for the accelerating source. Near Earth (X≈10 RE selected events support our basic concept. The proposed mechanism seems to reveal a fundamental building block of the substorm phenomenon and may be the basic process/structure, which is now

  6. Study of MHD events initiated by pellet injection into T-10 plasmas

    International Nuclear Information System (INIS)

    Kuteev, B.; Khimchenko, L.; Krylov, S.; Pavlov, Y.; Pustovitov, V.; Sarychev, D.; Sergeev, V.; Skokov, V.; Timokhin, V.

    2005-01-01

    There are several events which might be responsible for ultra fast transport of heat and particles during pellet ablation stage in a tokamak. Those are jumps of transport coefficients, plasma drifts in the pellet vicinity and MHD events with time scale significantly shorter than the pellet ablation time. The role of the latter is still not very well understood due to a lack of studies. This paper is devoted to detailed study of the effects during the pellet ablation phase (∼ one millisecond) with main objective to determine the relation between pellet (material Li, C., KCl, size and velocity) and plasma parameters ( q-value a the pellet position, plasma density and temperature) which initiate microsecond MHD events in plasma. The pellets were injected into both into Ohmic and ECE heated plasmas (up to 3 MW) in the T-10 tokamak at various stages of the plasma discharge, in a wide range from the very beginning up to the post-disruption stage. It is observed that at some conditions a pellet ablates in the plasma without accompanying MHD events. This occurs at the highest plasma densities even if a pellet penetrates through q=1 magnetic surface. The ablation rate corresponds to NGSM in this case. Small scale events may occur near rational magnetic surfaces and the ablation rate fluctuations may be explained by reconnection. Both increase of the longitudinal heat flow due to plasma conventional from higher temperature region and growth of the electric field generation supra-thermal electrons may be responsible for the enhanced ablation. Large scale MHD events envelop a region inside q<3. It is observed that the MHD-cooled area is not poloidally symmetric. Mechanisms of the phenomena observed and their consequences on tokamak operation are discussed. (Author)

  7. Active-passively mode-locked dye laser for diagnosis of laser-produced plasmas

    International Nuclear Information System (INIS)

    Teng, Y.L.; Fedosejevs, R.; Sigel, R.

    1981-03-01

    In this report an active-passively mode-locked, flashlamp-pumped dye laser for diagnosis of laser-produced plasmas is described. This dye laser system used as a pulsed light source for high-speed photography of laser-target experiments was synchronized to the ASTERIX III iodine laser pulse with better than 100 ps accuracy. The single pulse energy was 10 μJ, pulse duration less than 10 ps. In 111 shots clear shadowgrams were obtained during a total of 151 target shots, i.e. the system worked well in 74% of the shots. (orig.)

  8. Method and device for the powerful compression of laser-produced plasmas for nuclear fusion

    International Nuclear Information System (INIS)

    Hora, H.

    1975-01-01

    According to the invention, more than 10% of the laser energy are converted into mechanical energy of compression, in that the compression is produced by non-linear excessive radiation pressure. The time and local spectral and intensity distribution of the laser pulse must be controlled. The focussed laser beams must increase to over 10 15 W/cm 2 in less than 10 -9 seconds and the time variation of the intensities must be carried out so that the dynamic absorption of the outer plasma corona by rippling consumes less than 90% of the laser energy. (GG) [de

  9. Cylindrical stationary striations in surface wave produced plasma columns of argon

    Science.gov (United States)

    Kumar, Rajneesh; Kulkarni, Sanjay V.; Bora, Dhiraj

    2007-12-01

    Striations are a good example of manifestation of a glow discharge. In the present investigation, stationary striations in the surface wave produced plasma column are formed. Physical parameters (length, number, etc.) of such striations can be controlled by operating parameters. With the help of bifurcation theory, experimental results are explained by considering two-step ionization in the surface wave discharge mechanism in argon gas. It is also observed that the bifurcation parameter is a function of input power, working pressure, and tube radius.

  10. Characterization of Orthorhombic α-MoO3 Microplates Produced by a Microwave Plasma Process

    International Nuclear Information System (INIS)

    Klinbumrung, A.; Thongtem, S.; Thongtem, T.; Thongtem, S.; Thongtem, T.

    2012-01-01

    Orthorhombic α-MoO 3 microplates were produced from (NH 4 ) 6 Mo 7 O 24 H 2 O solid powder by a 900 W microwave plasma for 40, 50, and 60?min. Phase, morphologies, and vibration modes were characterized by X-ray diffraction (XRD), selected area electron diffraction (SAED), scanning electron microscopy (SEM), and Raman and Fourier transform infrared (FTIR) spectroscopy. Sixty min processing resulted in the best crystallization of the α-MoO 3 phase, with photoluminescence (PL) in a wavelength range of 430-440 nm.

  11. Nanosecond Pulsed Discharge in Water without Bubbles: A Fundamental Study of Initiation, Propagation and Plasma Characteristics

    Science.gov (United States)

    Seepersad, Yohan

    The state of plasma is widely known as a gas-phase phenomenon, but plasma in liquids have also received significant attention over the last century. Generating plasma in liquids however is theoretically challenging, and this problem is often overcome via liquid-gas phase transition preceding the actual plasma formation. In this sense, plasma forms in gas bubbles in the liquid. Recent work at the Drexel Plasma Institute has shown that nanosecond pulsed electric fields can initiate plasma in liquids without any initial cavitation phase, at voltages below theoretical direct-ionization thresholds. This unique regime is poorly understood and does not fit into any current descriptive mechanisms. As with all new phenomena, a complete fundamental description is paramount to understanding its usefulness to practical applications. The primary goals of this research were to qualitatively and quantitatively understand the phenomenon of nanosecond pulsed discharge in liquids as a means to characterizing properties that may open up niche application possibilities. Analysis of the plasma was based on experimental results from non-invasive, sub-nanosecond time-resolved optical diagnostics, including direct imaging, transmission imaging (Schlieren and shadow), and optical emission spectroscopy. The physical characteristics of the plasma were studied as a function of variations in the electric field amplitude and polarity, liquid permittivity, and pulse duration. It was found that the plasma size and emission intensity was dependent on the permittivity of the liquid, as well as the voltage polarity, and the structure and dynamics were explained by a 'cold-lightning' mechanism. The under-breakdown dynamics at the liquid-electrode interface were investigated by transmission imaging to provide evidence for a novel mechanism for initiation based on the electrostriction. This mechanism was proposed by collaborators on the project and developed alongside the experimental work in this

  12. Evaluation of pressure in a plasma produced by laser ablation of steel

    Science.gov (United States)

    Hermann, Jörg; Axente, Emanuel; Craciun, Valentin; Taleb, Aya; Pelascini, Frédéric

    2018-05-01

    We investigated the time evolution of pressure in the plume generated by laser ablation with ultraviolet nanosecond laser pulses in a near-atmospheric argon atmosphere. These conditions were previously identified to produce a plasma of properties that facilitate accurate spectroscopic diagnostics. Using steel as sample material, the present investigations benefit from the large number of reliable spectroscopic data available for iron. Recording time-resolved emission spectra with an echelle spectrometer, we were able to perform accurate measurements of electron density and temperature over a time interval from 200 ns to 12 μs. Assuming local thermodynamic equilibrium, we computed the plasma composition within the ablated vapor material and the corresponding kinetic pressure. The time evolution of plume pressure is shown to reach a minimum value below the pressure of the background gas. This indicates that the process of vapor-gas interdiffusion has a negligible influence on the plume expansion dynamics in the considered timescale. Moreover, the results promote the plasma pressure as a control parameter in calibration-free laser-induced breakdown spectroscopy.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  14. Mg-containing hydroxyapatite coatings produced by plasma electrolytic oxidation of titanium

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, Cesar Augusto; Rangel, Elidiane Cipriano; Durrant, Steven Frederick; Cruz, Nilson Cristino da, E-mail: cesar.augustoa@hotmail.com [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil). Lab. de Plasmas Tecnologicos; Delgado-Silva, Adriana de Oliveira [Universidade Federal de Sao Carlos (UFSCar), Sorocaba, SP (Brazil); Tabacniks, Manfredo H. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica

    2017-07-15

    Plasma Electrolytic Oxidation (PEO) is promising for the processing of biomaterials because it enables the production of surfaces with adjustable composition and structure. In this work, aimed at the improvement of the bioactivity of titanium, PEO has been used to grow calcium phosphide coatings on titanium substrates. The effects of the addition of magnesium acetate to the electrolytes on the composition of the coatings produced during 120 s on Ti disks using bipolar voltage pulses and solutions of calcium and magnesium acetates and sodium glycerophosphate as electrolytes have been studied. Scanning electron microscopy, X-ray energy dispersive spectroscopy, Rutherford backscattering spectroscopy, X-ray diffractometry with Rietveld refinement and profilometry were used to characterize the modified samples. Coatings composed of nearly 50 % of Mg-doped hydroxyapatite have been produced. In certain conditions up to 4% Mg can be incorporated into the coating without any observable significant structural modifications of the hydroxyapatite. (author)

  15. The application of selected radionuclides for monitoring of the D-D reactions produced by dense plasma-focus device.

    Science.gov (United States)

    Jednorog, S; Szydlowski, A; Bienkowska, B; Prokopowicz, R

    The dense plasma focus (DPF) device-DPF-1000U which is operated at the Institute of Plasma Physics and Laser Microfusion is the largest that type plasma experiment in the world. The plasma that is formed in large plasma experiments is characterized by vast numbers of parameters. All of them need to be monitored. A neutron activation method occupies a high position among others plasma diagnostic methods. The above method is off-line, remote, and an integrated one. The plasma which has enough temperature to bring about nuclear fusion reactions is always a strong source of neutrons that leave the reactions area and take along energy and important information on plasma parameters and properties as well. Silver as activated material is used as an effective way of neutrons measurement, especially when they are emitted in the form of short pulses like as it happens from the plasma produced in Dense Plasma-Focus devices. Other elements such as beryllium and yttrium are newly introduced and currently tested at the Institute of Plasma Physics and Laser Microfusion to use them in suitable activation neutron detectors. Some specially designed massive indium samples have been recently adopted for angular neutrons distribution measurements (vertical and horizontal) and have been used in the recent plasma experiment conducted on the DPF-1000U device. This choice was substantiated by relatively long half-lives of the neutron induced isotopes and the threshold character of the 115 In(n,n') 115m In nuclear reaction.

  16. The producing of an ECR plasma using 2450MHz Whistler Wave and the investigating of its parameters

    International Nuclear Information System (INIS)

    Fang Yude; Zhang Jiande; Fu Keming; Lu Xiangyu; Liu Dengcheng; Wang Xianyu; Xie Weidong; Bao Dinghua; Yin Xiejin

    1988-12-01

    A stable ECR plasma was produced and sustained in HER mirror using 2450MHz Whistler wave. The parameters of the ECR plasma and their chaining characters were studied in detail and were compared with those of the DC discharge plasmas. The conclusion is that the ECR plasma is a high ionizability, low temperature, middle density plasma, its peak density may much exceed the cutoff density of the pump wave (when ω = ω pe ) and arrive at the order of 10 12 cm -3 . The ECR plasma includes some high energy hot electrons (20Kev-200Kev) and middle energy warm electrons (< 20Kev). Those two kinds of electron created some strong X-ray emissions in a wide frequency range. The ECR plasma has higher edge density and can strongly interact with the wall. (author). 9 refs, 17 figs

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

    Science.gov (United States)

    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.

  18. Optical spectroscopy of laser-produced plasmas for standoff isotopic analysis

    Science.gov (United States)

    Harilal, S. S.; Brumfield, B. E.; LaHaye, N. L.; Hartig, K. C.; Phillips, M. C.

    2018-06-01

    Rapid, in-field, and non-contact isotopic analysis of solid materials is extremely important to a large number of applications, such as nuclear nonproliferation monitoring and forensics, geochemistry, archaeology, and biochemistry. Presently, isotopic measurements for these and many other fields are performed in laboratory settings. Rapid, in-field, and non-contact isotopic analysis of solid material is possible with optical spectroscopy tools when combined with laser ablation. Laser ablation generates a transient vapor of any solid material when a powerful laser interacts with a sample of interest. Analysis of atoms, ions, and molecules in a laser-produced plasma using optical spectroscopy tools can provide isotopic information with the advantages of real-time analysis, standoff capability, and no sample preparation requirement. Both emission and absorption spectroscopy methods can be used for isotopic analysis of solid materials. However, applying optical spectroscopy to the measurement of isotope ratios from solid materials presents numerous challenges. Isotope shifts arise primarily due to variation in nuclear charge distribution caused by different numbers of neutrons, but the small proportional nuclear mass differences between nuclei of various isotopes lead to correspondingly small differences in optical transition wavelengths. Along with this, various line broadening mechanisms in laser-produced plasmas and instrumental broadening generated by the detection system are technical challenges frequently encountered with emission-based optical diagnostics. These challenges can be overcome by measuring the isotope shifts associated with the vibronic emission bands from molecules or by using the techniques of laser-based absorption/fluorescence spectroscopy to marginalize the effect of instrumental broadening. Absorption and fluorescence spectroscopy probe the ground state atoms existing in the plasma when it is cooler, which inherently provides narrower

  19. W/Cu composites produced by low temperature Pulse Plasma Sintering

    International Nuclear Information System (INIS)

    Rosinski, M.S.; Fortuna, E.; Michalski, A.J.; Kurzydlowski, K.J.

    2006-01-01

    The plasma facing components (PFCs) must withstand the thermal, mechanical and neutron loads under cyclic mode of operation and vacuum. Despite that PFCs of ITER and demonstration reactors must assure reliability and long in service lifetime. For that reason PFCs are designed to be made of beryllium, tungsten or carbon fibre composites armours and copper based heat sink material. Such design concepts can only be used if joining methods of these dissimilar materials are resolved. Several techniques have been developed for joining W and Cu e. g. casting of pure Cu onto W, high temperature brazing, direct diffusion bonding or CVDs of W onto Cu. The main problem in the development of such joints is the large difference in the coefficients of thermal expansion, CTE (alpha Cu > 4 alpha W) and elastic modula (ECu > 0.2 EW). These differences result in large stresses at the W/Cu interfaces during manufacturing and/or during operation, which may lead to cracking or delamination reducing lifetime of the components. Possible solution to this problem is the use of W-Cu composites (FGM). W-Cu composites are widely used for spark erosion electrodes, in heavy duty circuit breakers and as heat sinks of microelectronic devices. They are commonly produced by infiltration of a porous sintered tungsten by liquid copper. Other technological route is powder metallurgy. Coatings can be produced by low pressure plasma spraying. All these methods, however, are known to have some disadvantages. For infiltration there is a 30 wt.% limit of Cu content while for powder metallurgy and plasma spraying techniques porosity is of concern. In our work the W-Cu composites of different composition were produced by pulse plasma sintering (PPS). This new method utilizes pulsed high electric discharges to heat the powders under uniaxial load. The arc discharges clean surface of powder particles and intensify diffusion. The total sintering time is reduced to several minutes. In our investigations various

  20. Comparison of glassy slag waste forms produced in laboratory crucibles and in a bench-scale plasma furnace

    International Nuclear Information System (INIS)

    Feng, X.; Wronkiewicz, D.J.; Brown, N.R.; Gong, M.; Whitworth, C.; Filius, K.; Battleson, D.

    1994-01-01

    Vitrification is currently the best demonstrated available technology for the disposal of high-level radioactive wastes. An innovative vitrification approach known as minimum additive waste stabilization (MAWS) is being developed. Both homogeneous glass and glassy slags have been used in implementing MAWS. Glassy slags (vitro-ceramics) are glass-crystal composites, and they are composed of various metal oxide crystalline phases embedded in an aluminosilicate glass matrix. Glassy slags with compositions developed in crucible melts at Argonne National Laboratory (ANL) were successfully produced in a bench-scale Retech plasma centrifugal furnace (PCF) by MSE, Inc. Detailed examinations of these materials showed that the crucible melts and the PCF produced similar glass and crystalline phases. The two sets of glassy slags exhibited similar chemical durability in terms of normalized releases of their major components. The slags produced in the PCF furnace using metals were usually less oxidized, although this had no effect on the corrosion behavior of the major components of the slags. However, the normalized release rate of cerium was initially lower for the PCF slags. This difference diminished with time as the redox sates of the metal oxides in slags began to be controlled by exposure to air in the tests. Thus, the deference in cerium release due to the differences in slag redox state may be transitory. The cerium solubility is a complex function of redox state and solution pH and Eh

  1. Optimising hard X-ray generation from laser-produced plasmas

    International Nuclear Information System (INIS)

    Lindheimer, C.

    1995-04-01

    The aim of this work is to increase the X-ray yield for a laser produced plasma by optimising the focusing conditions and temporal shape of the laser pulses. The focusing conditions are improved by introducing a control system that secures the laser target surface to exact focus within a range of a few micrometers, allowing continuously high laser intensity for plasma generation. The temporal shape of the laser pulses is changed by introducing a saturable absorber in the laser beam. The laser produces a substantial pre-pulse that heats and expands the target material prior to main pulse arrival. The saturable absorber can increase the main pulse/pre-pulse ratio of the laser pulse up to four orders of magnitude and consequently reduce expansion of the target material before the main pulse. The belief is that an increase in target density at the time of main pulse arrival will change the energy distribution of the X-rays, towards a more efficient X-ray production in the hard X-ray region. This report and the work connected to it, includes the preliminary measurements and results for these improvements. 17 refs

  2. Calculation for laser-produced plasmas conditions of thin middle-Z targets: Pt.I

    International Nuclear Information System (INIS)

    Peng Huimin; Zhang Guoping; Sheng Jiatian; Shao Yunfeng; Zhang Yinchun

    1988-01-01

    An one-dimentional non-LTE laser irradiated code was used to simulate the laser-produced plasmas conditions of thin middle Z targets with high intensities (about 10 13 W/cm 2 ) irradiation. Following physical processes are considered: bremsstrahlung, radiative ionization, collisional ionization by electrons and their inverse processes, Compton scattering. Fokker-Planck approximtaion is used in Compton scattering; the thermal flux limits are taken for electrons and ions in the calculating, and the multigroup flux-limited diffusion approximation is taken for the radiative transport equations. The average-atom model is used to calculate the population probabilities of atoms. Laser absorption via inverse bremsstrahlung is considered to be the most important in the simulation. Using laser beams with intensities 5 x 10 13 W/cm 2 and 1 x 10 14 W/cm 2 , λ L = 0.53 μm, τ = 450 ps to irradiate thin Se target from single-side and double-sides separately, the computational results for laser-produced plasmas conditions are well agree with experimental results

  3. Convective mechanism for inhibition of heat conduction in laser produced plasmas

    International Nuclear Information System (INIS)

    Lee, P.H.Y.; Willi, O.; Trainor, R.J.

    1984-01-01

    In laser-produced plasmas, the laser energy is absorbed only below and up to the critical density. For laser fusion applications, this energy must be transported beyond the corona via electron thermal conduction towards colder, higher density regions of the target to heat up material and cause ablation, which in turn generates an inward pressure to compress the fusion fuel. If the heat conduction is inhibited, the consequences will be a weaker ablation and therefore a weaker implosion. For many years now, the inhibition of heat conduction, i.e., the reduction of heat conduction relative to classical conduction, in laser-produced plasmas at relevant irradiances has been apparent from the large body of experimental evidence. Many mechanisms, such as dc magnetic fields, ion acoustic turbulence, and Weibel instabilities, have been proposed to be the cause of inhibition of heat conduction. Even improved calculations of the classical heat flux have been carried out to solve this problem. Nevertheless, no single one of the above mentioned mechanisms can explain the large inhibition observed in the experiments

  4. Compact laser-produced plasma EUV sources for processing polymers and nanoimaging

    International Nuclear Information System (INIS)

    Fiedorowicz, H.; Bartnik, A.; Jarocki, R.; Kostecki, J.; Szczurek, M.; Wachulak, P.

    2010-01-01

    Complete text of publication follows. Extreme ultraviolet (EUV) can be produced form a high-temperature plasma generated by interaction of high power laser pulses with matter. Laser plasma EUV sources are considered to be used in various applications in physics, material science, biomedicine, and technology. In the paper new compact laser plasma EUV sources developed for processing polymers and imaging are presented. The sources are based on a gas puff target formed by pulsed injection of a small amount of gas under high-pressure into a laser focus region. The use of the gas puff target instead of a solid target allows for efficient generation of EUV radiation without debris production. The compact laser plasma EUV source based on a gas puff target was developed for metrology applications. The EUV source developed for processing polymers is equipped with a grazing incidence axisymmetrical ellipsoidal mirror to focus EUV radiation in the relatively broad spectral range with the strong maximum near 10 nm. The size of the focal spot is about 1.3 mm in diameter with the maximum fluence up to 70 mJ/cm 2 . EUV radiation in the wavelength range of about 5 to 50 nm is produced by irradiation of xenon or krypton gas puff target with a Nd:YAG laser operating at 10 Hz and delivering 4 ns pulses of energy up to 0.8 J per pulse. The experiments on EUV irradiation of various polymers have been performed. Modification of polymer surfaces was achieved, primarily due to direct photo-etching with EUV photons and formation of micro- and nanostructures onto the surface. The mechanism of the interaction is similar to the UV laser ablation where energetic photons cause chemical bonds of the polymer chain to be broken. However, because of very low penetration depth of EUV radiation, the interaction region is limited to a very thin surface layer (<100 nm). This makes it possible to avoid degradation of bulk material caused by deeply penetrating UV radiation. The results of the studies

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

    International Nuclear Information System (INIS)

    Bent-Hansen, L.

    1991-01-01

    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 ± 0.004 min-1, corresponding to a wholebody unidirectional albumin clearance (Cl(0)) of 0.090 ± 0.009 ml(min*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*100 g)-1) and muscle (0.054 ml(min*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

  6. Studies of high repetition rate laser-produced plasma soft-X-ray amplifiers

    International Nuclear Information System (INIS)

    Cassou, K.

    2006-12-01

    The progress made as well on the Ti:Sa laser system, as in the control and the knowledge of laser produced X-UV sources allowed the construction of a X-UV laser station dedicated to the applications. My thesis work falls under the development of this station and more particularly on the characterization of a X-UV laser plasma amplifier. The experimental study relates to the coupling improvement of the pump infra-red laser with plasma within the framework of the transient collisional X-UV laser generation. These X-UV lasers are generated in a plasma formed by the interaction of a solid target and a laser pulse of approximately 500 ps duration, followed by a second infra-red laser pulse known as of pump (about 5 ps) impinging on the target in grazing incidence. For the first time, a complete parametric study was undertaken on the influence of the grazing angle on the pumping of the amplifying medium. One of the results was to reach very high peak brightness about 10 28 ph/s/mm 2 /mrad 2 /(0.1%bandwidth), which compares well with the free-electron laser brightness. Moreover, we modified then used a new two-dimensional hydrodynamic code with adaptive mesh refinement in order to understand the influence of the space-time properties of the infra-red laser on the formation and the evolution of the amplifying plasma. Our modeling highlighted the interest to use a super Gaussian transverse profile for the line focus leading to an increase in a factor two of the gain region size and a reduction of the electron density gradient by three orders of magnitude. These improvements should strongly increase the energy contained in X-UV laser beam. We thus used X-UV laser to study the appearance of transient defects produced by a laser IR on a beam-splitter rear side. We also began research on the mechanisms of DNA damage induced by a very intense X-UV radiation. (author)

  7. Initiation of arcing on tungsten surface exposed to steady state He plasmas

    Science.gov (United States)

    Kajita, Shin; Noiri, Yasuyuki; Ohno, Noriyasu

    2015-09-01

    Arcing was initiated in steady state helium plasmas by negatively biasing a tungsten electrode to around -500 V. On the tungsten electrode, nanostructures were grown by the plasma irradiation. In this study, we characterized the property of the initiated arcing by measuring the temporal evolutions of the electrode potential and the arc current. The ignition frequency and duration of arcing were presented from the potential measurements; the arc duration was in the range of changing the biasing voltage. The behavior of arc spots was observed with a fast framing camera. It was shown that the spots split frequently, and sometimes, they run on the surface independently. From the fluctuation of the arc current, the fractal feature of arcing was revealed.

  8. Initial conditions of non-equilibrium quark-gluon plasma evolution

    International Nuclear Information System (INIS)

    Shmatov, S.V.

    2002-01-01

    In accordance with the hydrodynamic Bjorken limit, the initial energy density and temperature for a chemical non-equilibrium quark-gluon system formed in the heavy ion collisions at the LHC are computed. The dependence of this value on the type of colliding nuclei and the collision impact parameter is studied. The principle possibility of the non-equilibrium quark-gluon plasma (QGP) formation in the light nuclei collisions is shown. The life time of QGP is calculated. (author)

  9. Initial particle loadings for a nonuniform simulation plasma in a magnetic field

    International Nuclear Information System (INIS)

    Naitou, Hiroshi; Kamimura, Tetsuo; Tokuda, Sinji.

    1978-09-01

    Improved methods for initially loading particles in a magnetized simulation plasma with nonuniform density and temperature distributions are proposed. In the usual guiding center loading (GCL), a charge separation coming from finite Larmor radius effects remains due to the difference between the guiding center density and the actual density. The modified guiding center loading (MGCL) presented here eliminates the electric field so generated and can be used for arbitrary density and temperature profiles. Some applications of these methods to actual simulations are given for comparison. The significance of these methods of initial particle loadings is also discussed. (author)

  10. Evaluation of initial plasma lactate values as a predictor of gastric necrosis and initial and subsequent plasma lactate values as a predictor of survival in dogs with gastric dilatation-volvulus: 84 dogs (2003-2007).

    Science.gov (United States)

    Green, Tiffany I; Tonozzi, Caroline C; Kirby, Rebecca; Rudloff, Elke

    2011-02-01

    To test whether an initial plasma lactate ≥ 6.0 mmol/L is associated with the presence of macroscopic gastric wall necrosis and overall survival in dogs presenting with gastric dilatation-volvulus (GDV). Additionally, if no association was identified we sought to identify a different predictive initial plasma lactate concentration and to examine whether serial plasma lactate concentrations provide better prediction of survival. Retrospective study over a 5-year period (2003-2007). Urban private referral small animal teaching hospital. Eighty-four client-owned dogs with a diagnosis of GDV and plasma lactate measurements. None. There was no statistically significant relationship found between survival and the presence of macroscopic gastric wall necrosis with the initial plasma lactate ≥ 6 mmol/L. There was a significant relationship between the initial plasma lactate >2.9 mmol/L for predicting necrosis and dogs that had an increased initial plasma lactate (>2.5 mmol/L) also had a subsequent plasma lactate measured within 12 hours of presentation, with 37/40 dogs surviving and 70% of these surviving dogs having the subsequent lactate decrease by ≥ 50% within 12 hours. The 3/40 that died failed to decrease their plasma lactate by ≥ 50% from the initial blood lactate. The results of this study indicate that an initial presenting plasma lactate concentration ≥ 6.0 mmol/L is not predictive of macroscopic gastric wall necrosis or survival in dogs presenting with GDV. A decrease in plasma lactate concentrations ≥ 50% within 12 hours may be a good indicator for survival. Limitations to the study include its retrospective nature, the small number of patients, and the number of dogs that were euthanized rather than allowed to progress to a natural outcome. © Veterinary Emergency and Critical Care Society 2011.

  11. Properties of highly electronegative plasmas produced in a multipolar magnetic-confined device with a transversal magnetic filter

    DEFF Research Database (Denmark)

    Draghici, Mihai; Stamate, Eugen

    2010-01-01

    Highly electronegative plasmas were produced in Ar/SF6 gas mixtures in a dc discharge with multipolar magnetic confinement and transversal magnetic filter. Langmuir probe and mass spectrometry were used for plasma diagnostics. Plasma potential drift, the influence of small or large area biased...... electrodes on plasma parameters, the formation of the negative ion sheath and etching rates by positive and negative ions have been investigated for different experimental conditions. When the electron temperature was reduced below 1 eV the density ratio of negative ion to electron exceeded 100 even for very...... low amounts of SF6 gas. The plasma potential drift could be controlled by proper wall conditioning. A large electrode biased positively had no effect on plasma potential for density ratios of negative ions to electrons larger than 50. For similar electronegativities or higher a negative ion sheath...

  12. Few femtosecond, few kilo-ampere electron bunch produced by a laser-plasma accelerator

    International Nuclear Information System (INIS)

    Lundh, O.; Lim, J.; Rechatin, C.; Ammoura, L.; Goddet, J.P.; Malka, V.; Faure, J.; Ben-Ismail, A.; Davoine, X.; Lefebvre, E.; Gallot, G.

    2011-01-01

    Particle accelerators driven by the interaction of ultra-intense and ultrashort laser pulses with a plasma can generate accelerating electric fields of several hundred giga-volts per meter and deliver high-quality electron beams with low energy spread, low emittance and up to 1 GeV peak energy. Moreover, it is expected they may soon be able to produce bursts of electrons shorter than those produced by conventional particle accelerators, down to femtosecond durations and less. Here we present wide-band spectral measurements of coherent transition radiation which we use for temporal characterization. Our analysis shows that the electron beam, produced using controlled optical injection, contains a temporal feature that can be identified as a 15 pC, 1.4-1.8 fs electron bunch (root mean square) leading to a peak current of 3-4 kA depending on the bunch shape. We anticipate that these results will have a strong impact on emerging applications such as short-pulse and short-wavelength radiation sources, and will benefit the realization of laboratory-scale free-electron lasers. (authors)

  13. Non-thermal plasma-activated water inactivation of food-borne pathogen on fresh produce

    International Nuclear Information System (INIS)

    Ma, Ruonan; Wang, Guomin; Tian, Ying; Wang, Kaile; Zhang, Jue; Fang, Jing

    2015-01-01

    Highlights: • We propose a new approach to treat S. aureus inoculated on strawberries by PAW. • PAW could inactivate S. aureus on strawberries via the Log Reduction results, further confirmed by CLSM and SEM. • The short-lived ROS in PAW are considered the most important agents in inactivation process. • No significant change was found in color, firmness and pH of the PAW treated strawberries. - Abstract: Non-thermal plasma has been widely considered to be an effective method for decontamination of foods. Recently, numerous studies report that plasma-activated water (PAW) also has outstanding antibacterial ability. This study presents the first report on the potential of PAW for the inactivation of Staphylococcus aureus (S. aureus) inoculated on strawberries. PAW treatments achieved a reduction of S. aureus ranging from 1.6 to 2.3 log at day-0 storage, while 1.7 to 3.4 log at day-4 storage. The inactivation efficiency depended on the plasma-activated time for PAW generation and PAW-treated time of strawberries inoculated with S. aureus. LIVE/DEAD staining and scanning electron microscopy results confirm that PAW could damage the bacterial cell wall. Moreover, optical emission spectra and oxidation reduction potential results demonstrate the inactivation is mainly attributed to oxidative stress induced by reactive oxygen species in PAW. In addition, no significant change was found in color, firmness and pH of the PAW treated strawberries. Thus, PAW can be a promising alternative to traditional sanitizers applied in the fresh produce industry.

  14. X-ray High-resolution Spectroscopy for Laser-produced Plasma

    Science.gov (United States)

    Barbato, F.; Scarpellini, D.; Malizia, A.; Gaudio, P.; Richetta, M.; Antonelli, L.

    The study of the emission spectrum gives information about the material generating the spectrum itself and the condition in which this is generated. The wavelength spectra lines are linked to the specific element and plasma conditions (electron temperature, density), while their shape is influenced by several physical effects like Stark and Doppler ones. In this work we study the X-ray emission spectra of a copper laser-produced plasma by using a spherical bent crystal spectrometer to measure the electron temperature. The facility used is the laser TVLPS, at the Tor Vergata University in Rome. It consists of a Nd:Glass source (in first harmonic - 1064 nm) whose pulse parameters are: 8 J in energy, time duration of 15 ns and a focal spot diameter of 200 μm. The adopted spectrometer is based on a spherical bent crystal of muscovite. The device combines the focusing property of a spherical mirror with the Bragg's law. This allows to obtain a great power resolution but a limited range of analysis. In our case the resolution is on average 80 eV. As it is well-known, the position of the detector on the Rowland's circle is linked to the specific spectral range which has been studied. To select the area to be investigated, we acquired spectra by means of a flat spectrometer. The selected area is centered on 8.88 Å. To calibrate the spectrum we wrote a ray-tracing MATLAB code, which calculates the detector alignment parameters and calibration curve. We used the method of line ratio to measure the electron temperature. This is possible because we assumed the plasma to be in LTE condition. The temperature value was obtained comparing the experimental one, given by the line ratio, with the theoretical one, preceded by FLYCHK simulations.

  15. Non-thermal plasma-activated water inactivation of food-borne pathogen on fresh produce

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ruonan; Wang, Guomin; Tian, Ying; Wang, Kaile [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zhang, Jue, E-mail: zhangjue@pku.edu.cn [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China); Fang, Jing [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China)

    2015-12-30

    Highlights: • We propose a new approach to treat S. aureus inoculated on strawberries by PAW. • PAW could inactivate S. aureus on strawberries via the Log Reduction results, further confirmed by CLSM and SEM. • The short-lived ROS in PAW are considered the most important agents in inactivation process. • No significant change was found in color, firmness and pH of the PAW treated strawberries. - Abstract: Non-thermal plasma has been widely considered to be an effective method for decontamination of foods. Recently, numerous studies report that plasma-activated water (PAW) also has outstanding antibacterial ability. This study presents the first report on the potential of PAW for the inactivation of Staphylococcus aureus (S. aureus) inoculated on strawberries. PAW treatments achieved a reduction of S. aureus ranging from 1.6 to 2.3 log at day-0 storage, while 1.7 to 3.4 log at day-4 storage. The inactivation efficiency depended on the plasma-activated time for PAW generation and PAW-treated time of strawberries inoculated with S. aureus. LIVE/DEAD staining and scanning electron microscopy results confirm that PAW could damage the bacterial cell wall. Moreover, optical emission spectra and oxidation reduction potential results demonstrate the inactivation is mainly attributed to oxidative stress induced by reactive oxygen species in PAW. In addition, no significant change was found in color, firmness and pH of the PAW treated strawberries. Thus, PAW can be a promising alternative to traditional sanitizers applied in the fresh produce industry.

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

    International Nuclear Information System (INIS)

    Kim, Y.W.

    1993-01-01

    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

  17. Plasma waves produced by an ion beam: observations by the VLF experiment on Porcupine

    International Nuclear Information System (INIS)

    Jones, D.

    1980-01-01

    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 fsub(cH + ). The main energy in the instabilities lies at approximately 3kHz for events when the Xe + source is close to the rocket, and at approximately 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 O + cyclotron harmonic waves. The second Xe + event on both flights exhibited an, as yet, unexplained harmonic structure related to fsub(cH + )/2. (Auth.)

  18. Time-resolved soft x-ray spectra from laser-produced Cu plasma

    International Nuclear Information System (INIS)

    Cone, K.V.; Dunn, J.; Baldis, H.A.; May, M.J.; Purvis, M.A.; Scott, H.A.; Schneider, M.B.

    2012-01-01

    The volumetric heating of a thin copper target has been studied with time resolved x-ray spectroscopy. The copper target was heated from a plasma produced using the Lawrence Livermore National Laboratory's Compact Multipulse Terrawatt (COMET) laser. A variable spaced grating spectrometer coupled to an x-ray streak camera measured soft x-ray emission (800-1550 eV) from the back of the copper target to characterize the bulk heating of the target. Radiation hydrodynamic simulations were modeled in 2-dimensions using the HYDRA code. The target conditions calculated by HYDRA were post-processed with the atomic kinetics code CRETIN to generate synthetic emission spectra. A comparison between the experimental and simulated spectra indicates the presence of specific ionization states of copper and the corresponding electron temperatures and ion densities throughout the laser-heated copper target.

  19. Complete chemical analysis of produced water by modern inductively coupled plasma spectroscopy (ICP)

    Energy Technology Data Exchange (ETDEWEB)

    Graham, G M; Sorbie, K S; Johnston, A; Boak, L S

    1997-12-31

    ICP (Inductively Coupled Plasma) spectroscopy is recognised as a very effective tool for monitoring ion compositions in many different waters. It has also been used by a number of laboratories to determine residual levels of phosphonate (PH) scale inhibitors in produced waters, based on phosphorus content. Until recently, it had not been used effectively to monitor phosphino-polycarboxylate (PPCA) returns. Large errors had frequently been observed where it had been applied. The poor detection limits and accuracy obtained for PPCA inhibitors relates to much lower amount of phosphorus present when compared with a typical phosphonate inhibitor. This paper demonstrates the effectiveness of IPC detection for PPCA and other phosphorus containing inhibitors by the use of modern instruments without the need of pre-treatment. 6 refs., 3 figs., 10 tabs.

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

    Science.gov (United States)

    Mantouvalou, Ioanna; Witte, Katharina; Grötzsch, Daniel; Neitzel, Michael; Günther, 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.

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

    Science.gov (United States)

    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.

  2. Sub-keV, subnanosecond measurements of x-ray spectra from laser-produced plasmas

    International Nuclear Information System (INIS)

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

    1977-01-01

    As part of the effort to extend our x-ray diagnostic capabilities, we have made x-ray spectral measurements of laser-produced plasmas 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 diode and filter, provided spectral information in the 100 to 300 eV region. Results from exploding pusher targets will be presented and compared with those of other diagnostic techniques and Lasnex calculations. Future expansion and modifications of the present system will be discussed

  3. Systems and methods for imaging using radiation from laser produced plasmas

    Science.gov (United States)

    Renard-Le Galloudec, Nathalie; Cowan, Thomas E.; Sentoku, Yasuhiko; Rassuchine, Jennifer

    2009-06-30

    In particular embodiments, the present disclosure provides systems and methods for imaging a subject using radiation emitted from a laser produced plasma generating by irradiating a target with a laser. In particular examples, the target includes at least one radiation enhancing component, such as a fluor, cap, or wire. In further examples, the target has a metal layer and an internal surface defining an internal apex, the internal apex of less than about 15 .mu.m, such as less than about 1 .mu.m. The targets may take a variety of shapes, including cones, pyramids, and hemispheres. Certain aspects of the present disclosure provide improved imaging of a subject, such as improved medical images of a radiation dose than typical conventional methods and systems.

  4. Crystalline and amorphous carbon nitride films produced by high-energy shock plasma deposition

    International Nuclear Information System (INIS)

    Bursilll, L.A.; Peng, Julin; Gurarie, V.N.; Orlov, A.V.; Prawer, S.

    1995-01-01

    High-energy shock plasma deposition techniques are used to produce carbon-nitride films containing both crystalline and amorphous components. The structures are examined by high-resolution transmission electron microscopy, parallel-electron-energy loss spectroscopy and electron diffraction. The crystalline phase appears to be face-centered cubic with unit cell parameter approx. a=0.63nm and it may be stabilized by calcium and oxygen at about 1-2 at % levels. The carbon atoms appear to have both trigonal and tetrahedral bonding for the crystalline phase. There is PEELS evidence that a significant fraction of the nitrogen atoms have sp 2 trigonal bonds in the crystalline phase. The amorphous carbon-nitride film component varies from essentially graphite, containing virtually no nitrogen, to amorphous carbon-nitride containing up to 10 at % N, where the fraction of sp 3 bonds is significant. 15 refs., 5 figs

  5. Microstructures and mechanical properties of 9Cr oxide dispersion strengthened steel produced by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Rui [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China); School of Metallurgy, Northeastern University, Shenyang 110819 (China); Lu, Zheng, E-mail: luz@atm.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China); Lu, Chenyang; Li, Zhengyuan [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China); Ding, Xueyong [School of Metallurgy, Northeastern University, Shenyang 110819 (China); Liu, Chunming [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China)

    2017-02-15

    Highlights: • A 9Cr-ODS steel was produced by mechanical alloying and spark plasma sintering. • Bimodal grain size distribution was observed. • Formation mechanism of bimodal grain size distribution was discussed. • The size and number density of nanoscale particles were obtained by SAXS and HRTEM. • The contribution of nano-sized particles to yield strength is dominating. - Abstract: 9Cr oxide dispersion strengthened (ODS) steel was fabricated by mechanical alloying (MA) and spark plasma sintering (SPS). The nano-sized particles, grain size distribution and mechanical properties of 9Cr-ODS steel sintered at 950 °C were studied by synchrotron radiation small angle X-ray scattering (SAXS), high-resolution transmission electron microscopy (HRTEM), electron backscatter diffraction (EBSD) and tensile experiment. The results showed that bimodal grain size distribution in the matrix is observed, which is attributed to the heterogeneous recrystallization process during the SPS. High-density nano-sized Y{sub 2}Ti{sub 2}O{sub 7} and some large oxides of Cr{sub 2}Mn(Ti)O{sub 4} are formed in 9Cr-ODS steel. The number density and average size of Y{sub 2}Ti{sub 2}O{sub 7} obtained from SAXS are 4.72 × 10{sup 22}/m{sup 3} and 4.4 nm, respectively. The yield strengths of 9Cr-ODS steel fabricated by SPS are compared with the typical 9Cr-ODS steel produced by HIP.

  6. Interaction of Cu and plastic plasmas as a method of forming laser produced Cu plasma streams with a narrow jet or pipe geometry

    Czech Academy of Sciences Publication Activity Database

    Kasperczuk, A.; Pisarczyk, T.; Chodukowski, T.; Kalinowska, Z.; Parys, P.; Ullschmied, Jiří; Krouský, Eduard; Pfeifer, Miroslav; Skála, Jiří; Klir, D.; Kravarik, J.; Kubes, P.; Rezac, K.; Pisarczyk, P.

    2011-01-01

    Roč. 18, č. 4 (2011), 044503/1-044503/4 ISSN 1070-664X R&D Projects: GA MŠk(CZ) 7E09092; GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z10100523 Keywords : laser-produced plasma * plasma streams * Cu-plasma jets * laser targets Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.147, year: 2011 http://pop.aip.org/ resource /1/phpaen/v18/i4/p044503_s1

  7. Associations Between Nurse-Guided Variables and Plasma Oxytocin Trajectories in Premature Infants During Initial Hospitalization.

    Science.gov (United States)

    Weber, Ashley; Harrison, Tondi M; Sinnott, Loraine; Shoben, Abigail; Steward, Deborah

    2018-02-01

    Oxytocin (OT) is a social hormone that may help researchers understand how nurse-guided interventions during initial infant hospitalization, such as supporting human milk expression, promoting comforting touch, and reducing exposure to stressors, affect preterm brain development. To determine whether factors related to human milk, touch, or stressor exposure are related to plasma OT trajectories in premature infants. Plasma from 33 premature infants, born gestational ages 25 to (Equation is included in full-text article.)weeks, was collected at 14 days of life and then weekly until 34 weeks' corrected gestational age (CGA). Variables related to feeding volumes of human milk and formula; touch, as indexed by skin-to-skin contact (SSC) and swaddled holding; and clinical stressors were extracted from the electronic medical record. Linear mixed-models tested associations between nurse-guided variables and plasma OT trajectories. In the final model, same-day SSC was positively related not only to plasma OT levels at 27 weeks' CGA (β= .938, P = .002) but also to a decline in plasma OT levels over time (β=-.177, P = .001). Volume of enteral feeds (mL/kg/d), its interaction with CGA, and number of stressful procedures were not statistically significant (β= .011, P = .077; β=-.002, P = .066; and β= .007, P = .062, respectively). Nurse-guided interventions are associated with infant plasma OT levels, suggesting nurses may impact the neurobiology of the developing premature infant. Replication with larger sample sizes and randomized controlled trial designs is needed to test effects of specific nursing interventions on infant OT.

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

    International Nuclear Information System (INIS)

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

    1999-01-01

    Atlas is a high current (approximately 30 MA peak, with a current risetime approximately 4.5 microsec), high energy (E stored = 24 MJ, E 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 (ρ/ρ 0 > 5, P > 10 Mbar), high magnetic fields (approximately 2,000 T), high strain and strain rates (var e psilon > 200%, dvar e psilon/dt approximately 10 4 to 10 6 s -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

  9. Effect of actuating voltage and discharge gap on plasma assisted detonation initiation process

    Science.gov (United States)

    Siyin, ZHOU; Xueke, CHE; Wansheng, NIE; Di, WANG

    2018-06-01

    The influence of actuating voltage and discharge gap on plasma assisted detonation initiation by alternating current dielectric barrier discharge was studied in detail. A loose coupling method was used to simulate the detonation initiation process of a hydrogen–oxygen mixture in a detonation tube under different actuating voltage amplitudes and discharge gap sizes. Both the discharge products and the detonation forming process assisted by the plasma were analyzed. It was found that the patterns of the temporal and spatial distributions of discharge products in one cycle keep unchanged as changing the two discharge operating parameters. However, the adoption of a higher actuating voltage leads to a higher active species concentration within the discharge zone, and atom H is the most sensitive to the variations of the actuating voltage amplitude among the given species. Adopting a larger discharge gap results in a lower concentration of the active species, and all species have the same sensitivity to the variations of the gap. With respect to the reaction flow of the detonation tube, the corresponding deflagration to detonation transition (DDT) time and distance become slightly longer when a higher actuating voltage is chosen. The acceleration effect of plasma is more prominent with a smaller discharge gap, and the benefit builds gradually throughout the DDT process. Generally, these two control parameters have little effect on the amplitude of the flow field parameters, and they do not alter the combustion degree within the reaction zone.

  10. Tribological and Corrosion Properties of Coatings Produced by Plasma Electrolytic Oxidation on the ZA27 Alloy

    Science.gov (United States)

    Li, Guangyin; Mao, Yifan; Li, Zhijian; Wang, Linlin; DaCosta, Herbert

    2018-05-01

    In this paper, a continuous and dense coating was deposited on samples of the ZA27 alloy through the plasma electrolytic oxidation (PEO) process to improve its wear and corrosion performance. A nontoxic and environmentally friendly inorganic salt, Na2SiO3, is chosen as electrolytes with different concentrations. The effect of the concentration of Na2SiO3 aqueous solutions on the coating performances was investigated. The coatings with 3Al2O3·2SiO2 (mullite), Zn2SiO4 and Al2O3 (either crystal phase or with some amorphous SiO2 phases) were formed by the PEO processes. It was found that the coating thickness increased with the increase in electrolyte concentration. However, the wear and corrosion resistance performance of the coatings did not improve as the coating's thickness increased. This was due to the fact that the coating produced with electrolytes of 10 g/L has a porous structure with large pore size. Among all the samples, coating produced by 15 g/L Na2SiO3 has the best wear and corrosion resistance, which is attributed to its continuous and dense structure with thickness of about 47 μm.

  11. Tribological and Corrosion Properties of Coatings Produced by Plasma Electrolytic Oxidation on the ZA27 Alloy

    Science.gov (United States)

    Li, Guangyin; Mao, Yifan; Li, Zhijian; Wang, Linlin; DaCosta, Herbert

    2018-04-01

    In this paper, a continuous and dense coating was deposited on samples of the ZA27 alloy through the plasma electrolytic oxidation (PEO) process to improve its wear and corrosion performance. A nontoxic and environmentally friendly inorganic salt, Na2SiO3, is chosen as electrolytes with different concentrations. The effect of the concentration of Na2SiO3 aqueous solutions on the coating performances was investigated. The coatings with 3Al2O3·2SiO2 (mullite), Zn2SiO4 and Al2O3 (either crystal phase or with some amorphous SiO2 phases) were formed by the PEO processes. It was found that the coating thickness increased with the increase in electrolyte concentration. However, the wear and corrosion resistance performance of the coatings did not improve as the coating's thickness increased. This was due to the fact that the coating produced with electrolytes of 10 g/L has a porous structure with large pore size. Among all the samples, coating produced by 15 g/L Na2SiO3 has the best wear and corrosion resistance, which is attributed to its continuous and dense structure with thickness of about 47 μm.

  12. A spectroscopic and microstructural study of oxide coatings produced on a Ti–6Al–4V alloy by plasma electrolytic oxidation

    International Nuclear Information System (INIS)

    Hussein, R.O.; Nie, X.; Northwood, D.O.

    2012-01-01

    Highlights: ► PEO (plasma electrolytic oxidation) for production of oxide coatings on a Ti–6Al–4V alloy. ► Two different current modes namely pulsed unipolar and bipolar was used. ► Optical emission spectroscopy (OES) was used to characterize the PEO plasma. ► This is the first attempt to characterize spectroscopically the PEO plasma of Ti and its alloys. ► The discharge behavior effect on the formation and structure of the coating was determined. - Abstract: In this study, we have used PEO (plasma electrolytic oxidation) for the production of oxide coatings on a Ti–6Al–4V alloy at two different current modes, namely pulsed unipolar and bipolar. Optical emission spectroscopy (OES) in the visible and near UV band (280–800 nm) was used to characterize the PEO plasma. The emission spectra were recorded and the plasma temperature profile versus processing time was constructed using a line intensity ratios method. The aim of this work was to study the effect of the process parameters, including current mode and pulse duration time, on the plasma characteristics, surface morphology and microstructure and corrosion resistance of oxides grown on Ti–6Al–4V by PEO process. Scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDS) and X-ray diffraction (XRD) were used to study the coating microstructure, morphology and phase composition. The corrosion resistance of the coated and uncoated samples was examined by potentiodynamic polarization in a 3.5% NaCl solution. It was found that the plasma temperature profiles are significantly influenced by changing the current mode from unipolar to bipolar. The strongest discharges that are initiated at the interface between the substrate and the coating can be reduced or eliminated by using a bipolar current mode. This produces a thinner, denser and more corrosion-resistant coating.

  13. X-ray spectroscopic characterization of laser produced hot dense plasmas; Caracterisation par spectroscopie X de plasmas chauds et denses crees par lasers de puissance

    Energy Technology Data Exchange (ETDEWEB)

    Kontogiannopoulos, N

    2007-12-15

    In this work we performed experiments of emission and absorption spectroscopy of laser produced plasmas, to provide well characterized spectral data which permit to benchmark atomic physics codes. More precisely, we produced xenon and krypton plasmas in NLTE (non local thermodynamic equilibrium) conditions and studied their emission spectra. In a second experiment, we characterized the absorption spectra of zinc sulfide and aluminium plasmas in LTE (local thermodynamic equilibrium) conditions.The first two chapters give an outline of the theory involved in the study of the emission and absorption plasma spectroscopy. Chapter 1 describes the different atomic processes occurring in a plasma. The LTE and the NLTE statistics ruling the equilibrium of the atomic processes are presented. Then, we give a brief description of the different codes of plasma atomic physics used in the analysis of our experimental data, namely HULLAC, SCO and TRANSPEC/AVERROES. In Chapter 2 the macroscopic theory of the radiation transport through a plasma is given. We describe also the self-similar model of Basko and the view factor approach, which permits us to calculate the heating conditions of the absorption foils achieved in the interior of the spherical gold cavity. Chapter 3 gives a description of the instruments used for realizing the two experiments, as well as the technical characteristics of the LULI2000 laser facility used to perform the experiments. Chapter 4 presents the experiment realized to characterize the emission spectra of the xenon and krypton plasmas in NLTE, as well the analysis of the experimental data with TRANSPEC/AVERROES. Finally, the experiment for measuring the absorption spectrum of the ZnS plasma mixture and the analysis of the experimental data with the code SCO are given in Chapter 5.

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

    International Nuclear Information System (INIS)

    Gurnett, D.A.; Anderson, R.R.; Smith, E.J.

    1979-01-01

    In this paper the authors present an initial survey of results from the plasma wave experiments on the ISEE-1 and -2 spacecraft which are in nearly identical orbits passing through the Earth's magneotsphere at radial distances out to about 22.5 Rsub(e). Essentially every crossing of the Earth's bow shock can be associated with an intense burst of electrostatic and whistler-mode turbulence at the shock, with substanial wave intensities in both the upstream and downstream regions. In the magnetosphere high resolution spectrograms of the electric field show an extremely complex distribution of plasma and radio emission, with numerous resonance and cutoff effects. High resolution spectrograms of kilometric radio emissions are also presented which show an extremely complex frequency-time structure with many closely spaced narrow-band emissions. (Auth.)

  15. Spectroscopy of reactive species produced by low-energy atmospheric-pressure plasma on conductive target material surface

    International Nuclear Information System (INIS)

    Yamada, Hiromasa; Sakakita, Hajime; Kato, Susumu; Kim, Jaeho; Kiyama, Satoru; Fujiwara, Masanori; Itagaki, Hirotomo; Ikehara, Yuzuru; Okazaki, Toshiya; Ikehara, Sanae; Nakanishi, Hayao; Shimizu, Nobuyuki

    2016-01-01

    A method for blood coagulation using low-energy atmospheric-pressure plasma (LEAPP) is confirmed as an alternative procedure to reduce tissue damage caused by heat. Blood coagulation using LEAPP behaves differently depending on working gas species; helium is more effective than argon in promoting fast coagulation. To analyse the difference in reactive species produced by helium and argon plasma, spectroscopic measurements were conducted without and with a target material. To compare emissions, blood coagulation experiments using LEAPP for both plasmas were performed under almost identical conditions. Although many kinds of reactive species such as hydroxyl radicals and excited nitrogen molecules were observed with similar intensity in both plasmas, intensities of nitrogen ion molecules and nitric oxide molecules were extremely strong in the helium plasma. It is considered that nitrogen ion molecules were mainly produced by penning ionization by helium metastable. Near the target, a significant increase in the emissions of reactive species is observed. There is a possibility that electron acceleration was induced in a local electric field formed on the surface. However, in argon plasma, emissions from nitrogen ion were not measured even near the target surface. These differences between the two plasmas may be producing the difference in blood coagulation behaviour. To control the surrounding gas of the plasma, a gas-component-controllable chamber was assembled. Filling the chamber with O 2 /He or N 2 /He gas mixtures selectively produces either reactive oxygen species or reactive nitrogen species. Through selective treatments, this chamber would be useful in studying the effects of specific reactive species on blood coagulation. (paper)

  16. Spectroscopy of reactive species produced by low-energy atmospheric-pressure plasma on conductive target material surface

    Science.gov (United States)

    Yamada, Hiromasa; Sakakita, Hajime; Kato, Susumu; Kim, Jaeho; Kiyama, Satoru; Fujiwara, Masanori; Itagaki, Hirotomo; Okazaki, Toshiya; Ikehara, Sanae; Nakanishi, Hayao; Shimizu, Nobuyuki; Ikehara, Yuzuru

    2016-10-01

    A method for blood coagulation using low-energy atmospheric-pressure plasma (LEAPP) is confirmed as an alternative procedure to reduce tissue damage caused by heat. Blood coagulation using LEAPP behaves differently depending on working gas species; helium is more effective than argon in promoting fast coagulation. To analyse the difference in reactive species produced by helium and argon plasma, spectroscopic measurements were conducted without and with a target material. To compare emissions, blood coagulation experiments using LEAPP for both plasmas were performed under almost identical conditions. Although many kinds of reactive species such as hydroxyl radicals and excited nitrogen molecules were observed with similar intensity in both plasmas, intensities of nitrogen ion molecules and nitric oxide molecules were extremely strong in the helium plasma. It is considered that nitrogen ion molecules were mainly produced by penning ionization by helium metastable. Near the target, a significant increase in the emissions of reactive species is observed. There is a possibility that electron acceleration was induced in a local electric field formed on the surface. However, in argon plasma, emissions from nitrogen ion were not measured even near the target surface. These differences between the two plasmas may be producing the difference in blood coagulation behaviour. To control the surrounding gas of the plasma, a gas-component-controllable chamber was assembled. Filling the chamber with O2/He or N2/He gas mixtures selectively produces either reactive oxygen species or reactive nitrogen species. Through selective treatments, this chamber would be useful in studying the effects of specific reactive species on blood coagulation.

  17. Group velocity measurement from the propagation of the ionization front in a surface-wave-produced plasma

    International Nuclear Information System (INIS)

    Cotrino, J.; Gamero, A.; Sola, A.; Lao, C.

    1989-01-01

    During the first instant, previous to steady-state in a surface-wave-produced plasma, an ionization front advance front the launcher to the plasma column end. The velocity of the ionization front is much slower than the group velocity of the surface wave, this give a reflection of the incident signal on the moving ionization front. In this paper, the authors use this effect to calculate the surface wave group velocity

  18. Traveling-wave laser-produced-plasma energy source for photoionization laser pumping and lasers incorporating said

    Science.gov (United States)

    Sher, Mark H.; Macklin, John J.; Harris, Stephen E.

    1989-09-26

    A traveling-wave, laser-produced-plasma, energy source used to obtain single-pass gain saturation of a photoionization pumped laser. A cylindrical lens is used to focus a pump laser beam to a long line on a target. Grooves are cut in the target to present a surface near normal to the incident beam and to reduce the area, and hence increase the intensity and efficiency, of plasma formation.

  19. Bent crystal X-ray optics for the diagnosis and applications of laser-produced plasmas

    International Nuclear Information System (INIS)

    Loetzsch, Robert

    2012-01-01

    The present thesis discussed several aspects of X-ray optics based on bent crystals and a number of applications of these optics. First, a deeper insight into the reflection properties of elastically bent perfect crystal optics was gained by the consideration of all deformation effects. It was shown that the reflection properties depend on the lateral position on the crystal, an effect that was not addressed before, neither experimentally nor theoretically. To investigate this effect, an apparatus for the measurement of Bragg angles of bent crystals with high angular resolution was built. It was measured that the lattice plane distances of two-dimensionally bent crystals vary laterally by up to 10 -4 . This effect has to be considered in high resolution X-ray spectroscopy and imaging with these bent crystals. It can explain discrepancies in theoretical and experimental spectrometer resolution with spherically bent crystals. Besides these principal investigations, in this thesis a number of X-ray optics were presented that demonstrate the application potential of bent crystal optics. This includes two optics that are used in the field of applications of laser-produced plasmas as high repeating hard X-ray sources. It was shown that an X-ray spectrometer based on full cylinder rings of highly oriented pyrolytic graphite is capable to record the rather weak single shot pulses from a high repeating 1 er-plasma X-ray source. This is possible due to the high collection efficiency of the instrument of up to 5.10 -4 . Furthermore, X-ray optics based on toroidally bent crystals that make it possible to spectrally select a bandwidth of ∝1 eV and focus the ultrashort X-ray pulses from such a laser-plasma source, were designed, prepared and characterized. It was shown that these bent crystals provide the calculated integrated reflectivity, the predicted bandwidth and focus to spot sizes smaller than 60 μm. A novel application of toroidally bent crystals was pointed out: a

  20. Study of electrons distribution produced by laser-plasma interaction on x-ray generation

    International Nuclear Information System (INIS)

    Nikzad, L.; Sadighi-Bonabi, R.

    2010-01-01

    Complete text of publication follows. In the present work, X-ray beams are generated from interaction of relativistic electron beams produced by interaction of 500 mJ, 30 femtosecond Ti:sapphire laser pulses with thin solid targets such as lead, molybdenum and tungsten. After interaction of an intense pulsed laser with He gas-jet, a micron-scale laser produced plasma, creates and accelerates electron bunches, which propagate in the ion channel produced in the wake of the laser pulse. When an electron bunch is injected into the bubble in phase with its field, it will gain relativistic energies within very short distance. These accelerated electrons with Megaelectron-Volt energy and different distributions, can interact with targets to generate X-ray radiation with Kiloelectron-Volt energy, providing to be close enough to the gas-jet, where the relativistic accelerated electrons exist. Here, to determine the results, Monte Carlo simulation (MCNP-4C code) is employed to present Bremsstrahlung and characteristic X-ray production by quasi-Maxwellian and quasi-monoenergetic electron beams for three samples with different thicknesses. The outcome shows that for one specific electron spectrum and one definite target, the energy which the maximum characteristic x-ray flux takes place, varies with thickness. Also, for each material the energy which this maximum happens is constant for all thicknesses, for both produced electron spectra. For each sample, x-ray flux is calculated for different thicknesses and the thickness which the maximum characteristic x-ray flux occurs is obtained. Besides, it is concluded that by increasing the atomic number of the target, maximum X-ray flux moves towards higher energy. Also, comparison of the results for three targets and two electron distributions shows that by using quasi-monoenergetic electron spectra, more intense and narrower characteristic X-ray can be produced compared to the quasi-Maxwellian electron distribution, almost for all

  1. Molybdenum plasma spray powder, process for producing said powder, and coating made therefrom

    International Nuclear Information System (INIS)

    Lafferty, W.D.; Cheney, R.F.; Pierce, R.H.

    1979-01-01

    Plasma spray powders of molybdenum particles containing 0.5 to 15 weight percent oxygen and obtained by reacting molybdenum particles with oxygen or oxides in a plasma, form plasma spray coatings exhibiting hardness comparable to flame sprayed coatings formed from molybdenum wire and plasma coatings of molybdenum powders. Such oxygen rich molybdenum powders may be used to form wear resistant coatings, such as for piston rings. (author)

  2. Simulation of some nonstationary astrophysical processes in laser-produced-plasma experiments

    International Nuclear Information System (INIS)

    Antonov, V.M.; Zakharov, Yu.P.; Orishich, A.M.; Ponomarenko, A.G.; Posukh, V.G.

    1985-01-01

    Preliminary results and calibration are reported on the astrophysical plasma dynamics simulator. This apparatus creates a spherical plasma cloud by the irradiation of a perlon filament target from two radial opposite directions by pulses of highly ionized background plasma in a high-vacuum chamber with diameter of 1.2 m and length of 5 m. The spherical plasma cloud simulates the exploding peripheric part of a supernova, expanding into the interstellar medium. (author)

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

    Science.gov (United States)

    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 μs. 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.

  4. Spatial-Resolved Measurement and Analysis of Extreme-Ultraviolet Emission Spectra from Laser-Produced Al Plasmas

    International Nuclear Information System (INIS)

    Cao Shi-Quan; Su Mao-Gen; Sun Dui-Xiong; Min Qi; Dong Chen-Zhong

    2016-01-01

    Extreme ultraviolet emission from laser-produced Al plasma is experimentally and theoretically investigated. Spatial-evolution emission spectra are measured by using the spatio-temporally resolved laser produced plasma technique. Based on the assumptions of a normalized Boltzmann distribution among the excited states and a steady-state collisional-radiative model, we succeed in reproducing the spectra at different detection positions, which are in good agreement with experiments. The decay curves about the electron temperature and electron density, as well as the fractions of individual Al ions and average ionization stage with increasing the detection distance are obtained by comparison with the experimental measurements. These parameters are critical points for deeply understanding the expanding and cooling of laser produced plasmas in vacuum. (paper)

  5. Laser-produced lithium plasma as a narrow-band extended ultraviolet radiation source for photoelectron spectroscopy.

    Science.gov (United States)

    Schriever, G; Mager, S; Naweed, A; Engel, A; Bergmann, K; Lebert, R

    1998-03-01

    Extended ultraviolet (EUV) emission characteristics of a laser-produced lithium plasma are determined with regard to the requirements of x-ray photoelectron spectroscopy. The main features of interest are spectral distribution, photon flux, bandwidth, source size, and emission duration. Laser-produced lithium plasmas are characterized as emitters of intense narrow-band EUV radiation. It can be estimated that the lithium Lyman-alpha line emission in combination with an ellipsoidal silicon/molybdenum multilayer mirror is a suitable EUV source for an x-ray photoelectron spectroscopy microscope with a 50-meV energy resolution and a 10-mum lateral resolution.

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

    International Nuclear Information System (INIS)

    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 ∼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

  7. Triglycerides produced in the livers of fasting rabbits are predominantly stored as opposed to secreted into the plasma

    Science.gov (United States)

    Tuvdendorj, Demidmaa; Zhang, Xiao-jun; Chinkes, David L.; Wang, Lijian; Wu, Zhanpin; Rodriguez, Noe A.; Herndon, David N.; Wolfe, Robert R.

    2015-01-01

    Objective The liver plays a central role in regulating fat metabolism; however, it is not clear how the liver distributes the synthesized triglycerides (TGs) to storage and to the plasma. Materials and Methods We have measured the relative distribution of TGs produced in the liver to storage and the plasma by means of U-13C16-palmitate infusion in anesthetized rabbits after an overnight fast. Results The fractional synthesis rates of TGs stored in the liver and secreted into the plasma were not significantly different (Stored vs. Secreted: 31.9 ± 0.8 vs. 27.7 ± 2.6 %•h−1, p > 0.05. However, the absolute synthesis rates of hepatic stored and secreted TGs were 543 ± 158 and 27 ± 7 nmol·kg−1·min−1 respectively, indicating that in fasting rabbits the TGs produced in the liver were predominately stored (92±3%) rather than secreted (8±3%) into the plasma. This large difference was mainly due to the larger pool size of the hepatic TGs which was 21±9-fold that of plasma TGs. Plasma free fatty acids (FFAs) contributed 47±1% of the FA precursor for hepatic TG synthesis, and the remaining 53±1% was derived from hepatic lipid breakdown and possibly plasma TGs depending on the activity of hepatic lipase. Plasma palmitate concentration significantly correlated with hepatic palmitoyl-CoA and TG synthesis. Conclusion In rabbits, after an overnight fast, the absolute synthesis rate of hepatic stored TGs was significantly higher than that of secreted due to the larger pool size of hepatic TGs. The net synthesis rate of TG was approximately half the absolute rate. Plasma FFA is a major determinant of hepatic TG synthesis, and therefore hepatic TG storage. PMID:25682063

  8. Studies on surface graft polymerization of acrylic acid onto PTFE film by remote argon plasma initiation

    International Nuclear Information System (INIS)

    Wang Chen; Chen Jierong

    2007-01-01

    The graft polymerization of acrylic acid (AAc) was carried out onto poly(tetrafluoroethylene) (PTFE) films that had been pretreated with remote argon plasma and subsequently exposed to oxygen to create peroxides. Peroxides are known to be the species responsible for initiating the graft polymerization when PTFE reacts with AAc. We chose different parameters of remote plasma treatment to get the optimum condition for introducing maximum peroxides (2.87 x 10 -11 mol/cm 2 ) on the surface. The influence of grafted reaction conditions on the grafting degree was investigated. The maximum grafting degree was 25.2 μg/cm 2 . The surface microstructures and compositions of the AAc grafted PTFE film were characterized with the water contact angle meter, Fourier-transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). Contact angle measurements revealed that the water contact angle decreased from 108 o to 41 o and the surface free energy increased from 22.1 x 10 -5 to 62.1 x 10 -5 N cm -1 by the grafting of the AAc chains. The hydrophilicity of the PTFE film surface was greatly enhanced. The time-dependent activity of the grafted surface was better than that of the plasma treated film

  9. Some E.U.V. spectra from laser produced plasma of heavy elements

    International Nuclear Information System (INIS)

    Even-Zohar, M.

    1975-09-01

    The spectra of Al, Mo, Ag, In, Sn, Cs, Ba, La, Ce, Ta and W produced by a Nd doped glass laser (energy about 15J, power near 5.10 8 W) were photographed in the region 20-240A utilizing a 3 m grazing incidence spectrograph. The continuum behavior is described. New identifications of Al XI, Mo XVII, Mo XVIII, Ag XII, Ag XVIII, Ag XIX, Ag XX, Ag XXI, In XIV, In XXI, In XXII, In XXIII, Sn XV, Sn XX, Sn XXI, Sn XXII, Sn XXIV, Cs VIII, Cs IX, Cs X, Cs XXVII, Ba IX, Ba X, Ba XI, La X, La XI, La XII and W VII are given. Lists of measured lines of Mo, Ag, Cs, Ba, La, and W are given. The spectra appear as absorption and emission lines where the transition from absorption to emission occurs in the same element for ions with ionization potential of 200 to 350eV. Absorption and emission spectra from the same ion of the same plasma are observed [fr

  10. Efficient soft x-ray generation in short wavelength laser produced plasmas

    International Nuclear Information System (INIS)

    Mochizuki, T.; Yamanaka, C.

    1987-01-01

    Intense x-ray generation in 1.053, 0.53, 0.26 μm laser-produced plasma has been investigated in the photon energy range of 0.1 to 3keV. The x-ray spectrum is found to have several humps which move to the higher energy side as the atomic number of the target increases. This atomic dependence is explained by a semi-Moseley's law and allows us to predict a target material most suitable for generating the photons of desired energies. Conversion efficiencies of 1.5 -- 3keV x-rays are obtained also as a function of laser wavelength at the intensity of 10/sup 13/W/cm/sup 2/. The conversion efficiency of keV x rays has been enhanced by a factor of 2 -- 3 with a controlled prepulse laser. From the semi-Moseley's law we find that cryogenic targets using either Xe or Kr in a liquid or solid phase may be most useful for a number of applications because they radiate 1 -- 3 keV x rays efficiently and never deposit on the x-ray optical components and the objects to be exposed

  11. Chemically produced nanostructured ODS-lanthanum oxide-tungsten composites sintered by spark plasma

    International Nuclear Information System (INIS)

    Yar, Mazher Ahmed; Wahlberg, Sverker; Bergqvist, Hans; Salem, Hanadi G.; Johnsson, Mats; Muhammed, Mamoun

    2011-01-01

    High purity W and W-0.9La 2 O 3 (wt.%) nanopowders were produced by a wet chemical route. The precursor was prepared by the reaction of ammonium paratungstate (APT) with lanthanum salt in aqueous solutions. High resolution electron microscopy investigations revealed that the tungstate particles were coated with oxide precipitates. The precursor powder was reduced to tungsten metal with dispersed lanthanum oxide. Powders were consolidated by spark plasma sintering (SPS) at 1300 and 1400 o C to suppress grain growth during sintering. The final grain size relates to the SPS conditions, i.e. temperature and heating rate, regardless of the starting powder particle size. Scanning electron microscopy revealed that oxide phases were mainly accumulated at grain boundaries while the tungsten matrix constituted of nanosized sub-grains. The transmission electron microscopy revealed that the tungsten grains consist of micron-scale grains and finer sub-grains. EDX analysis confirmed the presence of W in dispersed oxide phases with varying chemical composition, which evidenced the presence of complex oxide phases (W-O-La) in the sintered metals.

  12. Short-wavelength out-of-band EUV emission from Sn laser-produced plasma

    Science.gov (United States)

    Torretti, F.; Schupp, R.; Kurilovich, D.; Bayerle, A.; Scheers, J.; Ubachs, W.; Hoekstra, R.; Versolato, O. O.

    2018-02-01

    We present the results of spectroscopic measurements in the extreme ultraviolet regime (7-17 nm) of molten tin microdroplets illuminated by a high-intensity 3 J, 60 ns Nd:YAG laser pulse. The strong 13.5 nm emission from this laser-produced plasma (LPP) is of relevance for next-generation nanolithography machines. Here, we focus on the shorter wavelength features between 7 and 12 nm which have so far remained poorly investigated despite their diagnostic relevance. Using flexible atomic code calculations and local thermodynamic equilibrium arguments, we show that the line features in this region of the spectrum can be explained by transitions from high-lying configurations within the Sn{}8+-Sn{}15+ ions. The dominant transitions for all ions but Sn{}8+ are found to be electric-dipole transitions towards the n = 4 ground state from the core-excited configuration in which a 4p electron is promoted to the 5s subshell. Our results resolve some long-standing spectroscopic issues and provide reliable charge state identification for Sn LPP, which could be employed as a useful tool for diagnostic purposes.

  13. Ceramic-intermetallic composites produced by mechanical alloying and spark plasma sintering

    CERN Document Server

    Cabanas-Moreno, J G; Martínez-Sanchez, R; Delgado-Gutierrez, O; Palacios-Gomez, J; Umemoto, M

    1998-01-01

    Nano-and microcomposites of intermetallic (Co/sub 3/Ti, AlCo/sub 2 /Ti) and ceramic (TiN, Ti(C, N), Al/sub 2/O/sub 3/) phases have been produced by spark plasma sintering (SPS) of powders resulting from mechanical alloying of Al-Co-Ti elemental powder mixtures. The mechanically alloyed powders consisted of mixtures of nanocrystalline and amorphous phases which, on sintering, transformed into complex microstructures of the intermetallic and ceramic phases. For Al contents lower than about 30 at% in the original powder mixtures, the use of SPS led to porosities of 1-2% in the sintered compacts and hardness values as high as ~1700 kg/mm/sup 2/; in these cases, the composite matrix was TiN and Ti(C, N), with the Al/sub 2/O/sub 3/ phase found as finely dispersed particles in the matrix and the Co /sub 3/Ti and AlCo/sub 2/Ti phases as interdispersed grains. (19 refs).

  14. Instantaneous x-ray radiation energy from laser produced polystyrene plasmas for shock ignition conditions

    International Nuclear Information System (INIS)

    Shang, Wanli; Wei, Huiyue; Li, Zhichao; Yi, Rongqing; Zhu, Tuo; Song, Tianmin; Huang, Chengwu; Yang, Jiamin

    2013-01-01

    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 14 to 1.8 × 10 15 W/cm 2 . Numerical analysis of the laser energy transformation is performed, and the simulation results agree with the experimental data

  15. Growth kinetics and initial stage growth during plasma-enhanced Ti atomic layer deposition

    CERN Document Server

    Kim, H

    2002-01-01

    We have investigated the growth kinetics of plasma-enhanced Ti atomic layer deposition (ALD) using a quartz crystal microbalance. Ti ALD films were grown at temperatures from 20 to 200 deg. C using TiCl sub 4 as a source gas and rf plasma-produced atomic H as the reducing agent. Postdeposition ex situ chemical analyses of thin films showed that the main impurity is oxygen, mostly incorporated during the air exposure prior to analysis. The thickness per cycle, corresponding to the growth rate, was measured by quartz crystal microbalance as a function of various key growth parameters, including TiCl sub 4 and H exposure time, rf plasma power, and sample temperature. The growth rates were independent of TiCl sub 4 exposure above 1x10 sup 3 L, indicating typical ALD mode growth. The key kinetic parameters for Cl extraction reaction and TiCl sub 4 adsorption kinetics were obtained and the growth kinetics were modeled to predict the growth rates based upon these results. Also, the dependency of growth kinetics on d...

  16. Energy dependence of the stopping power of MeV 16O ions in a laser-produced plasma

    International Nuclear Information System (INIS)

    Sakumi, A.; Shibata, K.; Sato, R.; Tsubuku, K.; Nishimoto, T.; Hasegawa, J.; Ogawa, M.; Oguri, Y.; Katayama, T.

    2001-01-01

    The energy dependence of the stopping power of 16 O ions in a laser-produced plasma target was experimentally investigated in the projectile energy range of 150-350 keV/u. In order to produce the target plasma a Q-Switched Nd-glass laser was focused onto a small lithium hydride (LiH) pellet. The plasma electron temperature and the electron line density were 15 eV and 2x10 17 cm -2 , respectively. The energy loss of 16 O ions in the plasma was measured by a time-of-flight (TOF) method. We found that the stopping power in the plasma agreed with the theoretical estimation based on a modified Bohr equation with correction at low velocities. In this evaluation, the effective charge of the projectile was calculated by means of rate equations on the loss and capture of electrons. It has been also found that in this projectile energy range the stopping power of the 16 O ions in the plasma still increases with decreasing projectile energy, while it decreases in cold equivalent

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    Science.gov (United States)

    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 (λ0 ~ 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.

  19. Man-made vitreous fiber produced from incinerator ash using the thermal plasma technique and application as reinforcement in concrete.

    Science.gov (United States)

    Yang, Sheng-Fu; Wang, To-Mai; Lee, Wen-Cheng; Sun, Kin-Seng; Tzeng, Chin-Ching

    2010-10-15

    This study proposes using thermal plasma technology to treat municipal solid waste incinerator ashes. A feasible fiberization method was developed and applied to produce man-made vitreous fiber (MMVF) from plasma vitrified slag. MMVF were obtained through directly blending the oxide melt stream with high velocity compressed air. The basic technological characteristics of MMVF, including morphology, diameter, shot content, length and chemical resistance, are described in this work. Laboratory experiments were conducted on the fiber-reinforced concrete. The effects of fibrous content on compressive strength and flexural strength are presented. The experimental results showed the proper additive of MMVF in concrete can enhance its mechanical properties. MMVF products produced from incinerator ashes treated with the thermal plasma technique have great potential for reinforcement in concrete. 2010 Elsevier B.V. All rights reserved.

  20. New type of discharge-produced plasma source for extreme ultraviolet based on liquid tin jet electrodes

    NARCIS (Netherlands)

    Koshelev, K.N.; Krivtsun, V.M.; Ivanov, V.; Yakushev, O.; Chekmarev, A.; Koloshnikov, V.; Snegirev, E.; Medvedev, Viacheslav

    2012-01-01

    A new approach for discharge-produced plasma (DPP) extreme ultraviolet (EUV) sources based on the usage of two liquid metallic alloy jets as discharge electrodes has been proposed and tested. Discharge was ignited using laser ablation of one of the cathode jets. A system with two jet electrodes was

  1. Stimulated Brillouin backscattering and magnetic field generation in laser-produced plasmas

    International Nuclear Information System (INIS)

    Bawa'aneh, M.S.

    1999-01-01

    This thesis is concerned with aspects of laser-plasma interactions related to fusion reactions; in particular thermoelectric magnetic field generation around a hole dug in plasma by intense laser beams, and stimulated Brillouin back scattering (SBBS) from plasmas containing hot spots. A hole, of the size of the laser focal spot, is dug in the plasma when illuminated by intense laser if the laser pressure exceeds the plasma thermal pressure. This hole is found to have steep, radial density gradients. My first concern arose from the prediction that magnetic fields might be generated around the hole-plasma interface in places where the steep density gradients overlap with the non-aligned temperature gradients. When a high-power laser beam is focused on a solid pellet, plasma is formed at the surface. In order to create conditions for thermonuclear reactions in the interior of the pellet, an effective deposition of the laser energy to thermal energy of the pellet via laser-plasma coupling is necessary. When light irradiates a plasma collective processes occur, which can either enhance or reduce the light absorption. For a better understanding of the fusion problem a knowledge of the nature of these collective processes and of the fraction of light reflected from the plasma modes is required. Local hot spots seen experimentally lead to higher gain levels of scattered light. These local temperature inhomogeneities could lead to non-equilibrium distributions, which result in a free energy leading to some interesting phenomena in plasma. In the second part of the thesis stimulated Brillouin back scattering from an ion acoustic mode in a hot spot is studied. Temperature inhomogeneities lead to an ion acoustic instability, and to higher levels of SBBS gain, which leads to lower thresholds for the same electron to ion temperature ratios. This could be the answer for the observed high levels of scattering from hot spots. (author)

  2. Validity of spherical quantitative refractometry: application to laser-produced plasmas

    International Nuclear Information System (INIS)

    Benattar, R.; Popovics, C.

    1983-01-01

    We report an experimental laser technique of quantitative Schlieren imaging of spherical plasmas combined with streak camera recording. We show that quantitative refractometry applies for small values of refraction angles, i.e., when the law giving the refraction angle versus the impact parameter of rays passing through the plasma is a linearly decreasing function

  3. Characteristics of a plasma flow field produced by a metal array bridge foil explosion

    Science.gov (United States)

    Junying, WU; Long, WANG; Yase, LI; Lijun, YANG; Manzoor, SULTAN; Lang, CHEN

    2018-07-01

    To improve the energy utilization efficiency of metal bridge foil explosion, and increase the function range of plasmas, array bridge foil explosion experiments with different structures were performed. A Schlieren photographic measurement system with a double-pulse laser source was used to observe the flow field of a bridge foil explosion. The evolution laws of plasmas and shock waves generated by array bridge foil explosions of different structures were analyzed and compared. A multi-phase flow calculation model was established to simulate the electrical exploding process of a metal bridge foil. The plasma equation of state was determined by considering the effect of the changing number of particles and Coulomb interaction on the pressure and internal energy. The ionization degree of the plasma was calculated via the Saha–Eggert equation assuming conditions of local thermal equilibrium. The exploding process of array bridge foils was simulated, and the superposition processes of plasma beams were analyzed. The variation and distribution laws of the density, temperature, pressure, and other important parameters were obtained. The results show that the array bridge foil has a larger plasma jet diameter than the single bridge foil for an equal total area of the bridge foil. We also found that the temperature, pressure, and density of the plasma jet’s center region sharply increase because of the superposition of plasma beams.

  4. Critical ionization velocity as a mechanism for producing Titan's plasma tail

    International Nuclear Information System (INIS)

    Galeev, A.A.; Khabibrakhmanov, I.KH.

    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 nitrogen ions also may trigger instability. The kinetic energy of the newly formed ions will be conveyed to the electrons by plasma waves generated in the counterflow, thereby exciting the atmospheric atoms to emit radiation. The limiting plasma density and electron temperature in Titan's plasma tail and the frequency spectrum of the waves that develop are determined and compared against the Voyager measurements. 11 references

  5. Mass-producible method for preparation of a carbon-coated graphite@plasma nano-silicon@carbon composite with enhanced performance as lithium ion battery anode

    International Nuclear Information System (INIS)

    Chen, Hedong; Wang, Zhoulu; Hou, Xianhua; Fu, Lijun; Wang, Shaofeng; Hu, Xiaoqiao; Qin, Haiqing; Wu, Yuping

    2017-01-01

    Carbon-coated core-shell structure artificial graphite@plasma nano-silicon@carbon (AG@PNSi@C) composite, applying as lithium ion battery anode material, has been prepared via spray drying method. The plasma nano-silicon (<100 nm), which contained amorphous silicon, was synthesized by radio frequency induction plasma system with the high temperatures processing capability and high quench rates. The artificial graphite in the composite acts as the core which supports the particle and provides electroconductivity, while PNSi attached on the surface of the core, enhances the specific capacity of the composite. The as prepared composite shows superior performance as anode in lithium-ion batteries, regarding to the initial Coulombic efficiency and cycle life. The initial Coulombic efficiency of AG@PNSi@C electrode is 81.0% with a discharge capacity of 553 mAh g −1 and a recharge capacity of 448 mAh g −1 . During cycling, AG@PNSi@C exhibits excellent performance with a very low capacity fading that the discharge capacity maintains 498.2 mAh g −1 and 449.4 mAh g −1 after 250 cycles and 500 cycles. AG@PNSi@C also shows enhanced resistance against high current density. Besides the remarkable electrochemical performances, the facile and mass-producible synthesis process makes the AG@PNSi@C composite very promising for its application in lithium-ion batteries.

  6. Discharge characteristics and hydrodynamics behaviors of atmospheric plasma jets produced in various gas flow patterns

    Science.gov (United States)

    Setsuhara, Yuichi; Uchida, Giichiro; Nakajima, Atsushi; Takenaka, Kosuke; Koga, Kazunori; Shiratani, Masaharu

    2015-09-01

    Atmospheric nonequilibrium plasma jets have been widely employed in biomedical applications. For biomedical applications, it is an important issue to understand the complicated mechanism of interaction of the plasma jet with liquid. In this study, we present analysis of the discharge characteristics of a plasma jet impinging onto the liquid surface under various gas flow patterns such as laminar and turbulence flows. For this purpose, we analyzed gas flow patters by using a Schlieren gas-flow imaging system in detail The plasma jet impinging into the liquid surface expands along the liquid surface. The diameter of the expanded plasma increases with gas flow rate, which is well explained by an increase in the diameter of the laminar gas-flow channel. When the gas flow rate is further increased, the gas flow mode transits from laminar to turbulence in the gas flow channel, which leads to the shortening of the plasm-jet length. Our experiment demonstrated that the gas flow patterns strongly affect the discharge characteristics in the plasma-jet system. This study was partly supported by a Grant-in-Aid for Scientific Research on Innovative Areas ``Plasma Medical Innovation'' (24108003) from the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT).

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

    Science.gov (United States)

    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 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 (λ= 263 nm, δt = 10 psec) beamlets (50μm 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.

  8. High beta capture and mirror confinement of laser produced plasmas. Semiannual report, April 1, 1977--September 30, 1977

    International Nuclear Information System (INIS)

    Haught, A.F.; Tomlinson, R.G.; Ard, W.B.

    1977-09-01

    The LITE research program is addressing two aspects of mirror confinement physics. ECRH heating of the confined LITE plasma is being investigated as a means for producing a local electrostatic well to trap cold ions within the plasma and provide DCLC stabilization without the energy drain effects obtained with a cold stabilizing stream. Concurrently, the heavy ion beam probe diagnostic being developed in LITE to experimentally measure the space potential within a minimum-B mirror plasma. During the period, 10-A beam injection focused on the target location has been achieved with the neutral beam source; investigations of hot ion building have been carried out with both a laser produced and a washer gun target; calculations modeling the ECRH stabilization have been performed, the experimental program defined, and preparations for the ECRH stabilization investigation undertaken; and the high current cesium source and high resolution electrostatic analyzer have been developed for the heavy ion beam probe. The physics of the ECRH stabilization model is studied, and conditions necessary to produce a local potential well for trapping cold ions are examined. An analysis of the stabilizing effect of this potential dip on the DCLC mode is presented. The heavy ion probe, under development for direct measurement of the mirror plasma space potential, is discussed. Using Thomson scattering measurements to calibrate the complex response of an electron cyclotron resonance microwave radiometer, measurements have been made of the time history of the electron temperature for the decaying mirror confined laser plasma target with and without streaming plasma stabilization and are reported

  9. The Influence of spot size on the expansion dynamics of nanosecond-laser-produced copper plasmas in atmosphere

    International Nuclear Information System (INIS)

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

    2013-01-01

    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 ∼0.1 mm to ∼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 ∼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.

  10. Plasma device

    International Nuclear Information System (INIS)

    Thode, L.E.

    1981-01-01

    A relativistic electron beam generator or accelerator produces a high-voltage electron beam which is modulated to initiate electron bunching within the beam which is then applied to a high-density target plasma which typically comprises DT, DD, or similar thermonuclear gas at a density of 10 17 to 10 20 electrons per cubic centimeter. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region of the high-density plasma target. The high-temperature plasma can be used to heat a high Z material to generate radiation. Alternatively, a tunable radiation source is produced by using a moderate Z gas or a mixture of high Z and low Z gas as the target plasma. (author)

  11. Model of an electric field produced by viscous interaction in the plasma sheet of the magnetotail

    International Nuclear Information System (INIS)

    Erkaev, N.V.

    1996-01-01

    Two-dimensional model of flow in a plasma layer of magnetotail is considered with account of low viscosity. The general Ohm's law is used for electric current. The role of viscous forces is most sufficient in boundary layers, which expand with moving away along the flow and located along the boundaries of plasma layer and solar wind. Auto model solution, describing the distribution of potential and velocity in boundary layers was obtained. The solution for boundary layers dictates boundary conditions for determination of large-scale distribution of electric potential in plasma layer. 7 refs., 4 figs

  12. Inductively coupled plasma-mass spectrometry: an initial assessment of the VG isotopes Plasmaquad

    International Nuclear Information System (INIS)

    Brown, R.M.; Pickford, C.J.

    1985-04-01

    The Chemical Analysis Group has been approached by a British Scientific instrument maker regarding the possibility of the group participating in a Department of Trade and Industry sponsored scheme whereby we would have a 12 month period to assess the advantages and disadvantages of a new analytical technique, Inductively Coupled Plasma-Mass Spectrometry. This report details our initial assessment of the instrument, carried out in order to decide whether to participate in the scheme. We have attempted to discover whether the instrument meets the claims made of it in advertising literature, and have attempted to compare the technique with another, proven technique, Inductively Coupled Plasma - Optical Emission Spectroscopy. The Plasmaquad offers excellent sensitivity for almost all of the elements of the periodic table, giving a distinct improvement over the Chemical Analysis Group's present capabilities for many elements. The isotope ratio measuring ability is important, as the Group has no such capability at the moment and a demand for this type of measurement is foreseen. Our conclusions, while inevitably somewhat subjective, form the basis for recommending Harwell to participate in the scheme. (author)

  13. Plasma-activated medium (PAM) kills human cancer-initiating cells.

    Science.gov (United States)

    Ikeda, Jun-Ichiro; Tanaka, Hiromasa; Ishikawa, Kenji; Sakakita, Hajime; Ikehara, Yuzuru; Hori, Masaru

    2018-01-01

    Medical non-thermal plasma (NTP) treatments for various types of cancers have been reported. Cells with tumorigenic potential (cancer-initiating cells; CICs) are few in number in many types of tumors. CICs efficiently eliminate anti-cancer chemicals and exhibit high-level aldehyde dehydrogenase (ALDH) activity. We previously examined the effects of direct irradiation via NTP on cancer cells; even though we targeted CICs expressing high levels of ALDH, such treatment affected both non-CICs and CICs. Recent studies have shown that plasma-activated medium (PAM) (culture medium irradiated by NTP) selectively induces apoptotic death of cancer but not normal cells. Therefore, we explored the anti-cancer effects of PAM on CICs among endometrioid carcinoma and gastric cancer cells. PAM reduced the viability of cells expressing both low and high levels of ALDH. Combined PAM/cisplatin appeared to kill cancer cells more efficiently than did PAM or cisplatin alone. In a mouse tumor xenograft model, PAM exerted an anti-cancer effect on CICs. Thus, our results suggest that PAM effectively kills both non-CICs and CICs, as does NTP. Therefore, PAM may be a useful new anti-cancer therapy, targeting various cancer cells including CICs. © 2017 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.

  14. Microwave plasma initiated graft copolymerization modification of monomers onto PTFE surface

    International Nuclear Information System (INIS)

    Guan Weishu; Wen Yunjian; Fang Yan; Yin Yongxiang

    1996-02-01

    A graft copolymerization modification technique of monomers onto polytetrafluoroethylene (PTFE) surface initiated by a 2.45 GHz non-equilibrium microwave plasma has been investigated. Standard X-Ray Photoelectron Spectroscopy (XPS), Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (sEM) and wetting techniques were used for examination and analysis of samples. Considerable changes in chemical structure, composition and in morphology of grafted surface of PTFE were found. Results showed the occurrence of noticeable defluorination and cross-linked structure on grafted surface, and indicated that different kinds and contents of oxygen-containing functional groups were introduced into the surface of PTFE. Wetting and adhesion experiment of the sample proved that significant improvements in hydrophilicity and adhesion of surface were exhibited. These results confirmed the success of grafting. (8 refs., 7 figs., 1 tab.)

  15. Effect of irradiation angle on the efficiency of formation of multiply charged ions in a laser-produced plasma

    International Nuclear Information System (INIS)

    Bedilov, M R; Beisembaeva, Kh B; Tsoi, T G; Satybaldiev, T B; Sabitov, M S

    2000-01-01

    Mass spectrometry is used to investigate the emission behaviour and the characteristics of multiply charged ions in a plasma produced at small angles of incidence of laser radiation (α∼20 0 ) and also at grazing incidence (α∼85 0 ). It is found that upon grazing incidence of the laser radiation onto a target, the efficiency of production of multiply charged ions is reduced compared to that for α∼20 0 . However, this geometry of laser irradiation of solids can be used for the elemental analysis of surface layers of a sample. (interaction of laser radiation with matter. laser plasma)

  16. X-ray spectrum in the range (6-12) A emitted by laser-produced plasma of samarium

    International Nuclear Information System (INIS)

    Louzon, Einat; Henis, Zohar; Levi, Izhak; Hurvitz, Gilad; Ehrlich, Yosi; Fraenkel, Moshe; Maman, Shlomo; Mandelbaum, Pinchas

    2009-01-01

    A detailed analysis of the x-ray spectrum emitted by laser-produced plasma of samarium (6-12 A) is presented, using ab initio calculations with the HULLAC relativistic code and isoelectronic considerations. Resonance 3d-nf (n=4 to 7), 3p-4d, 3d-4p, and 3p-4s transitions in Ni samarium ions and in neighboring ionization states (from Mn to Zn ions) were identified. The experiment results show changes in the fine details of the plasma spectrum for different laser intensities.

  17. Physical principles of the surface plasma method for producing beams of negative ions

    International Nuclear Information System (INIS)

    Bel'chenko, Yu.I.; Dimov, G.I.; Dudnikov, V.G.

    1977-01-01

    The processes which are important for the production of intense beams of negative ions from surface plasma sources (SPS) are examined. The formation of negative ions when atomic particles interact with a surface is analyzed on the basis of both experimental results obtained when a surface was bombarded with beams and recently developed theoretical considerations of reflection, scattering, and electron exchange. The characteristic features of these processes in SPS, when a surface is bombarded with intense fluxes of plasma particles, are revealed in special experiments. The characteristics of generation and acceleration of the bombarding particles in a gas discharge SPS plasma, the characteristics of transportation of negative ions through the plasma toward the beam forming system, the role of cesium in SPS, and the characteristics of formation of the intense negative ion beams as well as the removal of parasite electrons from the beam

  18. Space-time resolved measurements of spontaneous magnetic fields in laser-produced plasma

    Czech Academy of Sciences Publication Activity Database

    Pisarczyk, T.; Gus’kov, S.Yu.; Dudžák, Roman; Chodukowski, T.; Dostál, Jan; Demchenko, N. N.; Korneev, Ph.; Kalinowska, Z.; Kalal, M.; Renner, Oldřich; Šmíd, Michal; Borodziuk, S.; Krouský, Eduard; Ullschmied, Jiří; Hřebíček, Jan; Medřík, Tomáš; Golasowski, Jiří; Pfeifer, Miroslav; Skála, Jiří; Pisarczyk, P.

    2015-01-01

    Roč. 22, č. 10 (2015), č. článku 102706. ISSN 1070-664X R&D Projects: GA MŠk LM2010014; GA MŠk(CZ) LD14089; GA ČR GPP205/11/P712 Grant - others:FP7(XE) 284464 Program:FP7 Institutional support: RVO:61389021 ; RVO:68378271 Keywords : space-time resolved spontaneous magnetic field (SMF) * Laser System Subject RIV: BL - Plasma and Gas Discharge Physics; BL - Plasma and Gas Discharge Physics (FZU-D) OBOR OECD: Fluids and plasma physics (including surface physics); Fluids and plasma physics (including surface physics) (FZU-D) Impact factor: 2.207, year: 2015 http://scitation.aip.org/content/aip/journal/pop/22/10/10.1063/1.4933364

  19. Propagation velocities of laser-produced plasmas from copper wire targets and water droplets

    Science.gov (United States)

    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.

  20. Holographic interferometry of isolated deuterium plasmas produced by a CO2 laser

    International Nuclear Information System (INIS)

    Gatenby, P.V.; Walker, A.C.

    1978-10-01

    The application of double exposure fractional fringe holographic interferometry to measurements of electron density in a plasma generated by irradiation of a freely falling pellet of solid deuterium with a focused CO 2 laser pulse is discussed. A particularly simple technique is used for processing and reconstructing the holograms and this is described in detail. A summary and discussion of the results is included with the emphasis on the observed evolution of the deuterium plasma over the duration of the laser irradiation. (author)

  1. Asymmetry of Stark-broadened Layman lines from laser-produced plasmas

    International Nuclear Information System (INIS)

    Joyce, R.F.; Woltz, L.A.; Hooper, C.F. Jr.

    1986-01-01

    This paper discusses three significant causes of spectral line asymmetry: the ion-quadrupole interaction, the quadratic Stark effect and fine structure splitting that are included in the calculation of Lyman line profiles emitted by highly-ionized hydrogenic radiators in a dense, hot plasma. The line asymmetries are shown to be strongly dependent on the plasma density, indicating that the asymmetry may be of use as a density diagnostic

  2. Experimental study of the behavior of two laser produced plasmas in air

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zefeng; Wei, Wenfu; Han, Jiaxun; Wu, Jian, E-mail: jxjawj@gmail.com; Li, Xingwen; Jia, Shenli [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Shaanxi 710049 (China)

    2015-07-15

    The interactions among two laser ablated Al plasmas and their shock wave fronts (SWFs) induced by double laser pulses in air were studied experimentally. The evolution processes, including the expansion and interaction of the two plasmas and their shocks, were investigated by laser shadowgraphs, schlieren images, and interferograms. Remarkably, the distribution of the compressed air and the laser plasmas during the colliding process was clearly obtained using the Mach-Zehnder interferometer. From the refractive index profiles, typical plasmas density and gas density behind the shock front were estimated as ∼5.2 × 10{sup 18 }cm{sup −3} and ∼2.4 × 10{sup 20 }cm{sup −3}. A stagnation layer formed by the collision of gas behind the shock front is observed. The SWFs propagated, collided, and reflected with a higher velocity than plasmas. The results indicated that the slower plasma collided at middle, leading to the formation of the soft stagnation.

  3. Emission study of alumina plasma produced by a KrF laser

    Energy Technology Data Exchange (ETDEWEB)

    Yahiaoui, K., E-mail: kyahiaoui@cdta.dz [Centre de Développement des Technologies Avancées, cité 20 aout 1956, BP 17, Baba Hassen, Alger (Algeria); Abdelli-Messaci, S.; Messaoud-Aberkane, S.; Kerdja, T. [Centre de Développement des Technologies Avancées, cité 20 aout 1956, BP 17, Baba Hassen, Alger (Algeria); Kellou, H. [Université des Sciences et de la Technologie Houari Boumediene, BP 32, El-Allia, 16111 Bab-Ezzouar, Alger (Algeria)

    2014-03-01

    We report on the plasma emission formed from an α-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/cm{sup 2} 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. - Highlights: • Ablated mass measurements of α-alumina target irradiated by a laser in nanosecond regime. • Optical emission spectroscopy of alumina plasma. • Fast imaging diagnostic of alumina plume using ICCD camera.

  4. Spectral and ion emission features of laser-produced Sn and SnO2 plasmas

    Science.gov (United States)

    Hui, Lan; Xin-Bing, Wang; Du-Luo, Zuo

    2016-03-01

    We have made a detailed comparison of the atomic and ionic debris, as well as the emission features of Sn and SnO2 plasmas under identical experimental conditions. Planar slabs of pure metal Sn and ceramic SnO2 are irradiated with 1.06 μm, 8 ns Nd:YAG laser pulses. Fast photography employing an intensified charge coupled device (ICCD), optical emission spectroscopy (OES), and optical time of flight emission spectroscopy are used as diagnostic tools. Our results show that the Sn plasma provides a higher extreme ultraviolet (EUV) conversion efficiency (CE) than the SnO2 plasma. However, the kinetic energies of Sn ions are relatively low compared with those of SnO2. OES studies show that the Sn plasma parameters (electron temperature and density) are lower compared to those of the SnO2 plasma. Furthermore, we also give the effects of the vacuum degree and the laser pulse energy on the plasma parameters. Project supported by the National Natural Science Foundation of China (Grant No. 11304235) and the Director Fund of WNLO, China.

  5. Measurement of Laser Plasma Instability (LPI) Driven Light Scattering from Plasmas Produced by Nike KrF Laser

    Science.gov (United States)

    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 (1˜3 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 (0.5˜4.0 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.

  6. Potential formation in a collisionless plasma produced in an open magnetic field in presence of volume negative ion source

    International Nuclear Information System (INIS)

    Phukan, Ananya; Goswami, K. S.; Bhuyan, P. J.

    2014-01-01

    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 (λ D )

  7. Diagnostics of plasma produced by femtosecond laser pulse impact upon a target with an internal nanostructure

    International Nuclear Information System (INIS)

    Skobelev, I. Yu.; Faenov, A. Ya.; Gasilov, S. V.; Pikuz, T. A.; Pikuz, S. A.; Magunov, A. I.; Boldarev, A. S.; Gasilov, V. A.

    2010-01-01

    X-ray diagnostics of the interaction of femtosecond laser pulses with intensities of 10 16 -10 18 W/cm 2 with CO 2 clusters and frozen nanosize water particles is carried out. The stage of cluster expansion and the formation of a plasma channel, which governs the parameters of the formed X-ray radiation source and accelerated ion flows, is studied. The measurements are based on recording spatially resolved X-ray spectra of H- and He-like oxygen ions. Utilization of Rydberg transitions for spectra diagnostics makes it possible to determine plasma parameters on a time scale of t ∼ 10 ps after the beginning of a femtosecond pulse. The role of the rear edge of the laser pulse in sustaining the plasma temperature at a level of ∼100 eV in the stage of a nonadiabatic cluster expansion is shown. The analysis of the profiles and relative intensities of spectral lines allows one to determine the temperature and density of plasma electrons and distinguish the populations of 'thermal' ions and ions that are accelerated up to energies of a few tens of kiloelectronvolts. It is shown that the use of solid clusters made of frozen nanoscale water droplets as targets leads to a substantial increase in the number of fast He-like ions. In this case, however, the efficiency of acceleration of H-like ions does not increase, because the time of their ionization in plasma exceeds the time of cluster expansion.

  8. Stainless steel coatings produced through atmospheric plasma spraying study of in flight powder behavior and coating structure

    International Nuclear Information System (INIS)

    Denoirjean, A.; Denoirjean, P.; Fauchais, P.; Labbe, J.C.; Khan, A.A.

    2005-01-01

    The Stainless Steel coatings deposited through Atmospheric Plasma Spraying over mild steel surface present an interest from commercial point of view, especially for the applications where corrosion resistance or inertness towards severe environment is required. Atmospheric Plasma Spraying is fast and relatively less expensive choice as compared to Vacuum Plasma Spraying, the only limitation being the extremely reactive nature of metallic powders used. A study of the behaviour of metallic powders within an Atmospheric Plasma Jet is presented in view of better understanding and eventual improvement in coating properties. Metallic powder particles show very interesting features when individual particles are collected after passing them through a DC Blown Arc Thermal Plasma Jet under Atmospheric Pressure. The spraying was carried out under air which makes the significance of these results even more interesting from the industrial point of view. Proper control of Spraying Parameters can help produce Stainless Steel coatings of reasonably low porosity and a typical lamellar microstructure. The results of SEM, AFM and XRD are discussed. A strange oxidation phenomenon under highly non equilibrium conditions is observed. (author)

  9. X-ray emission spectra of the plasma produced by an ultrashort laser pulse in cluster targets

    International Nuclear Information System (INIS)

    Stenz, C; Bagnoud, V; Blasco, F; Roche, J R; Salin, F; Faenov, A Ya; Skobelev, I Yu; Magunov, A I; Pikuz, T A

    2000-01-01

    The first observation of x-ray emission spectra of multiply charged ions in the plasma produced by a 35-fs laser pulse with an intensity up to 10 17 W cm -2 in CO 2 and Kr gas jet targets is reported. The emission in the wavelength ranges of the 1snp-1s 2 (n=3-6) transitions of O VII ions and the Ly α line of O VIII ions, as well as of the (2s 1/2 2p 6 3p 3/2 ) 1 -2s 2 2p 6 1 S 0 and (2s 1/2 2p 6 3p 1/2 ) 1 -2s 2 2p 6 1 S 0 lines of Ne-like KrXXVII ions testifies that the highly ionised plasma is formed by collision processes in clusters. Modelling the shape of the spectral lines of oxygen ions by including the principal mechanisms of broadening and absorption in optically dense plasmas reveals that the main contribution to the time-integrated intensity is made by the plasma with the parameters N e =(2-20)x10 20 cm -3 and T e =100 - 115 eV. (interaction of laser radiation with matter. laser plasma)

  10. Interferometric characterization of laboratory plasma astrophysical jets produced by a 1-μs pulsed power driver

    International Nuclear Information System (INIS)

    Plouhinec, Damien; Zucchini, Frederic; Loyen, Arnaud; Sol, David; Combes, Philippe; Grunenwald, Julien; Hammer, David A.

    2014-01-01

    A high current driver based on microsecond LTD technology has been used to perform laboratory plasma astrophysics studies using a conical wire array load coupled a 950 kA, 1.2-μs pulsed power generator. A plasma jet is generated as a result of the on-axis shock formed by the ablation streams from the wires of a conical tungsten wire-array load together with conservation of the axial momentum. The aim of this paper is to produce a scaled-down laboratory simulation of astrophysical Herbig-Haro plasma jets occurring during star formation along with some of their interactions with the interstellar medium, such as a cross wind. Due to the relatively long duration of the current pulse delivered by the driver, the jet develops on a 2-μs timescale and grows up to 100 mm. A time-resolved laser interferometer has been fielded to measure the plasma areal electron density as a function of time in and around the plasma jets. The setup consists of a continuous diode-pumped solid state laser (5 W-532 nm), a Mach-Zehnder interferometer and fast gated visible multi frame camera. (authors)

  11. Theory and experimental show up of axial magnetic fields self-generated in dense laser-produced plasmas

    International Nuclear Information System (INIS)

    El Tamer, M.

    1986-09-01

    The work presented in this thesis concerns the magnetic fields generated in laser produced plasma. A summary of the theoretical and experimental studies concerning the toroidal magnetic fields and realised by different groups of research is presented. Then, we present our original contribution on the generation of axial magnetic fields by the dynamo effect. The experimental work for the detection of magnetic field is based on the Faraday rotation and Zeeman effects. The experimental diagrams are detailed and discussed. The experimental results are presented and compared to the theory. Finaly, we present some consequences of the generation of the axial magnetic fields in laser produced plasma as a discussion of the thermal conductivity [fr

  12. Measurement of the energy loss of heavy ions in laser-produced plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Knobloch-Maas, Renate

    2009-11-25

    The interaction of ions with plasma is not yet fully understood today, although it is important for inertial fusion technology. During recent years, the energy loss of heavy ions in plasma has therefore been a subject of research in the Laser and Plasma Physics group of Darmstadt University of Technology. Several experiments were carried out at the Gesellschaft fuer Schwerionenforschung (GSI) in Darmstadt using laser-created plasma, thereby taking advantage of the unique combination of GSI's accelerator facility and the laser system nhelix, which is also described in this work. The experiments focus on the measurement of the energy loss of medium heavy ions in a plasma created by directly heating a thin carbon foil with the nhelix laser, at an energy of about 50 J. In order to measure the energy loss using a time-of-flight method, a stop detector is used to register the arrival of the ion pulses after passing the plasma and a 12 m drift space. At the beginning of the work on this thesis, the ion detector types formerly used were found to be inadequately suited to the difficult task; this was changed during this thesis. The ion detector has to be able to temporarily resolve ion pulses with a frequency of 108 MHz and a width (FWHM) of 3 ns at a very low current. It also has to withstand the X-ray burst from the plasma with a dead time shorter than the difference between the X-ray and the ion time of flight between the plasma and the detector. In order to satisfy these and other demands, a new diamond detector was designed and has now been used for several measurements. In addition to the new detector, other improvements were made concerning the diagnostics and the laser. The laser-created plasma now reaches a maximum temperature exceeding 200 eV and a free electron density of up to 10{sup 22} cm{sup -3}. With this greatly improved setup, energy loss data could be obtained with a temporal resolution several times better than before, using an ion beam with a

  13. Synthesis and characterization of carbon coated nanoparticles produced by a continuous low-pressure plasma process

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, Vineet; Neergat, Manoj [Indian Institute of Technology Bombay, Department of Energy Science and Engineering (India); Bhandarkar, Upendra, E-mail: bhandarkar@iitb.ac.in [Indian Institute of Technology Bombay, Department of Mechanical Engineering (India)

    2011-09-15

    Core-shell nanoparticles coated with carbon have been synthesized in a single chamber using a continuous and entirely low-pressure plasma-based process. Nanoparticles are formed in an argon plasma using iron pentacarbonyl Fe(CO){sub 5} as a precursor. These particles are trapped in a pure argon plasma by shutting off the precursor and then coated with carbon by passing acetylene along with argon as the main background gas. Characterization of the particles was carried out using TEM for morphology, XPS for elemental composition and PPMS for magnetic properties. Iron nanoparticles obtained were a mixture of FeO and Fe{sub 3}O{sub 4}. TEM analysis shows an average size of 7-14 nm for uncoated particles and 15-24 nm for coated particles. The effect of the carbon coating on magnetic properties of the nanoparticles is studied in detail.

  14. Using self-generated harmonics as a diagnostic of high intensity laser-produced plasmas

    International Nuclear Information System (INIS)

    Krushelnick, K; Watts, I; Tatarakis, M; Gopal, A; Wagner, U; Beg, F N; Clark, E L; Clarke, R J; Dangor, A E; Norreys, P A; Wei, M S; Zepf, M

    2002-01-01

    The interaction of high intensity laser pulses (up to I∼10 20 W cm -2 ) with plasmas can generate very high order harmonics of the laser frequency (up to the 75th order have been observed). Measurements of the properties of these harmonics can provide important insights into the plasma conditions which exist during such interactions. For example, observations of the spectrum of the harmonic emission can provide information of the dynamics of the critical surface as well as information on relativistic non-linear optical effects in the plasma. However, most importantly, observations of the polarization properties of the harmonics can provide a method to measure the ultra-strong magnetic fields (greater than 350 MG) which can be generated during these interactions. It is likely that such techniques can be scaled to provide a significant amount of information from experiments at even higher intensities

  15. Measurement of the energy loss of heavy ions in laser-produced plasmas

    International Nuclear Information System (INIS)

    Knobloch-Maas, Renate

    2009-01-01

    The interaction of ions with plasma is not yet fully understood today, although it is important for inertial fusion technology. During recent years, the energy loss of heavy ions in plasma has therefore been a subject of research in the Laser and Plasma Physics group of Darmstadt University of Technology. Several experiments were carried out at the Gesellschaft fuer Schwerionenforschung (GSI) in Darmstadt using laser-created plasma, thereby taking advantage of the unique combination of GSI's accelerator facility and the laser system nhelix, which is also described in this work. The experiments focus on the measurement of the energy loss of medium heavy ions in a plasma created by directly heating a thin carbon foil with the nhelix laser, at an energy of about 50 J. In order to measure the energy loss using a time-of-flight method, a stop detector is used to register the arrival of the ion pulses after passing the plasma and a 12 m drift space. At the beginning of the work on this thesis, the ion detector types formerly used were found to be inadequately suited to the difficult task; this was changed during this thesis. The ion detector has to be able to temporarily resolve ion pulses with a frequency of 108 MHz and a width (FWHM) of 3 ns at a very low current. It also has to withstand the X-ray burst from the plasma with a dead time shorter than the difference between the X-ray and the ion time of flight between the plasma and the detector. In order to satisfy these and other demands, a new diamond detector was designed and has now been used for several measurements. In addition to the new detector, other improvements were made concerning the diagnostics and the laser. The laser-created plasma now reaches a maximum temperature exceeding 200 eV and a free electron density of up to 10 22 cm -3 . With this greatly improved setup, energy loss data could be obtained with a temporal resolution several times better than before, using an ion beam with a diameter of only

  16. Time-resolved x-ray line diagnostics of laser-produced plasmas

    International Nuclear Information System (INIS)

    Kauffman, R.L.; Matthews, D.L.; Kilkenny, J.D.; Lee, R.W.

    1982-01-01

    We have examined the underdense plasma conditions of laser irradiated disks using K x-rays from highly ionized ions. A 900 ps laser pulse of 0.532 μm light is used to irradiate various Z disks which have been doped with low concentrations of tracer materials. The tracers whose Z's range from 13 to 22 are chosen so that their K x-ray spectrum is sensitive to typical underdense plasma temperatures and densities. Spectra are measured using a time-resolved crystal spectrograph recording the time history of the x-ray spectrum. A spatially-resolved, time-integrated crystal spectrograph also monitors the x-ray lines. Large differences in Al spectra are observed when the host plasma is changed from SiO 2 to PbO or In. Spectra will be presented along with preliminary analysis of the data

  17. Silica nanoparticles produced by DC arc plasma from a solid raw materials

    Science.gov (United States)

    Kosmachev, P. V.; Vlasov, V. A.; Skripnikova, N. K.

    2017-05-01

    Plasma synthesis of SiO2 nanoparticles in experimental atmospheric pressure plasma reactor on the basis of DC arc plasma generator was presented in this paper. Solid high-silica raw materials such as diatomite from Kamyshlovskoye deposit in Russia, quartzite from Chupinskoye deposit in Russia and milled window glass were used. The obtained nanoparticles were characterized based on their morphology, chemical composition and size distribution. Scanning electron microscopy, laser diffractometry, nitrogen absorption (Brunauer-Emmett-Teller method), X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy were used to characterize the synthesized products. The obtained silica nanoparticles are agglomerated, have spherical shape and primary diameters between 10-300 nm. All samples of synthesized nanopowders were compared with commercial nanopowders.

  18. Characteristics of ICR-produced peripheral plasma in the URAGAN-3M torsatron

    International Nuclear Information System (INIS)

    Besedin, N.T.; Chechkin, V.V.; Fomin, I.P.

    1991-01-01

    Some plasma parameters outside the confinement volume near the last closed magnetic surface (LCMS) and in the divertor fluxes were studied by probe and microwave techniques during ICR production and heating of the plasma in the Uragan-3M torsatron (1=3, m=9, R o =100cm, a-bar≤11 cm, l (a-bar)≤0.29; B o ≤20kG, n-bar e ≅2x10 12 cm -3 , T i (0)=200-300 eV, T e (0)≅100 eV). When moving around the LCMS, the steepness of the radial density, electron temperature and potential profiles increases with the distance away from the ''rib'' of the LCMS. The quasi-steady radial electric field E r near the LCMS exceeds 100 V/cm and is directed outwards, opposite to the calculated ambipolar electric field inside the confinement volume. It is shown that the total flow of the diverted plasma in the spacing between two helical windings consists of (i) a weakly mobile non-resonant component which is presumably formed at the periphery due to ionization, and (ii) a component whose value and poloidal location are sensitive to resonance conditions for RF power absorption, this flow being apparently formed by a plasma diffusing through the LCMS and/or generated near the LCMS, where the filed E r is localized. Based on plasma parameters measurements after the RF pulse is switched off, a qualitative model of peripheral plasma dynamics after the end of the RF heating is constructed. 23 refs.; 13 figs. (author)

  19. Simulation of perturbation produced by an absorbing spherical body in collisionless plasma

    Energy Technology Data Exchange (ETDEWEB)

    Krasovsky, V. L., E-mail: vkrasov@iki.rssi.ru; Kiselyov, A. A., E-mail: alexander.kiselyov@stonehenge-3.net.ru; Dolgonosov, M. S. [Russian Academy of Sciences, Space Research Institute (Russian Federation)

    2017-01-15

    A steady plasma state reached in the course of charging of an absorbing spherical body is found using computational methods. Numerical simulations provide complete information on this process, thereby allowing one to find the spatiotemporal dependences of the physical quantities and observe the kinetic phenomena accompanying the formation of stable electron and ion distributions in phase space. The distribution function of trapped ions is obtained, and their contribution to the screening of the charged sphere is determined. The sphere charge and the charge of the trapped-ion cloud are determined as functions of the unperturbed plasma parameters.

  20. Study of X-ray spectrum of laser-produced gold plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Busquet, M. (CEA Centre d' Etudes de Limeil, 94 - Villeneuve-Saint-Georges (France)); Pain, D.; Bauche, J.; Luc-Koenig, E. (Centre National de la Recherche Scientifique, 91 - Orsay (France). Lab. Aime Cotton)

    1985-02-01

    Aiming at the spectroscopic diagnostic of gold plasmas, we have studied the wavelengths and intensities of X-ray spectral lines emitted in the range 4.4 to 6.2 angstroms by a target made of gold alloyed to a few percent of aluminium irradiated by a laser pulse. Aluminium yields the wavelength calibration and a monitoring of the temperature and the density of the plasma. The main features of the gold spectrum in this spectral range are due to the 3d-4f, 3p-4s and 3d-4p transitions of gold in the Co I through Cu I isoelectronic sequences.

  1. Study of X-ray spectrum of laser-produced gold plasmas

    International Nuclear Information System (INIS)

    Busquet, M.; Pain, D.; Bauche, J.; Luc-Koenig, E.

    1985-01-01

    Aiming at the spectroscopic diagnostic of gold plasmas, we have studied the wavelengths and intensities of X-ray spectral lines emitted in the range 4.4 to 6.2 angstroms by a target made of gold alloyed to a few percent of aluminium irradiated by a laser pulse. Aluminium yields the wavelength calibration and a monitoring of the temperature and the density of the plasma. The main features of the gold spectrum in this spectral range are due to the 3d-4f, 3p-4s and 3d-4p transitions of gold in the Co I through Cu I isoelectronic sequences. (orig.)

  2. Bragg scattering of electromagnetic waves by microwave-produced plasma layers

    Science.gov (United States)

    Kuo, S. P.; Zhang, Y. S.

    1990-01-01

    A set of parallel plasma layers is generated by two intersecting microwave pulses in a chamber containing dry air at a pressure comparable to the upper atmosphere. The dependencies of breakdown conditions on the pressure and pulse length are examined. The results are shown to be consistent with the appearance of tail erosion of the microwave pulse caused by air breakdown. A Bragg scattering experiment, using the plasma layers as a Bragg reflector, is then performed. Both time domain and frequency domain measurements of wave scattering are conducted. The experimental results are found to agree very well with the theory.

  3. Simulation of perturbation produced by an absorbing spherical body in collisionless plasma

    International Nuclear Information System (INIS)

    Krasovsky, V. L.; Kiselyov, A. A.; Dolgonosov, M. S.

    2017-01-01

    A steady plasma state reached in the course of charging of an absorbing spherical body is found using computational methods. Numerical simulations provide complete information on this process, thereby allowing one to find the spatiotemporal dependences of the physical quantities and observe the kinetic phenomena accompanying the formation of stable electron and ion distributions in phase space. The distribution function of trapped ions is obtained, and their contribution to the screening of the charged sphere is determined. The sphere charge and the charge of the trapped-ion cloud are determined as functions of the unperturbed plasma parameters.

  4. Detailed hydrodynamic and X-ray spectrocsopic analysis of a laser-produced rapidly-explanding aluminium plasma

    Czech Academy of Sciences Publication Activity Database

    Chambers, D. M.; Glenzer, S. H.; Hawreliak, J.; Wolfrum, E.; Gouveia, A.; Lee, R. W.; Marjoribanks, R. S.; Renner, Oldřich; Sondhauss, P.; Topping, S.

    2001-01-01

    Roč. 71, - (2001), s. 237-247 ISSN 0022-4073 Grant - others:US DOE(US) DESG03-99D-P00297; US Department of Energy(US) W-7405 ENG 48 Institutional research plan: CEZ:AV0Z1010921 Keywords : laser produced plasma * x-ray spectroscopy * Thomson scattering * hydrocode Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.493, year: 2001

  5. Collisional plasma transport: two-dimensional scalar formulation of the initial boundary value problem and quasi one-dimensional models

    International Nuclear Information System (INIS)

    Mugge, J.W.

    1979-10-01

    The collisional plasma transport problem is formulated as an initial boundary value problem for general characteristic boundary conditions. Starting from the full set of hydrodynamic and electrodynamic equations an expansion in the electron-ion mass ratio together with a multiple timescale method yields simplified equations on each timescale. On timescales where many collisions have taken place for the simplified equations the initial boundary value problem is formulated. Through the introduction of potentials a two-dimensional scalar formulation in terms of quasi-linear integro-differential equations of second order for a domain consisting of plasma and vacuum sub-domains is obtained. (Auth.)

  6. Measurements of electron density and temperature profiles in plasma produced by Nike KrF laser for laser plasma instability research

    Science.gov (United States)

    Oh, Jaechul; Weaver, J. L.; Karasik, M.; Chan, L. Y.

    2015-08-01

    A grid image refractometer (GIR) has been implemented at the Nike krypton fluoride laser facility of the Naval Research Laboratory. This instrument simultaneously measures propagation angles and transmissions of UV probe rays (λ = 263 nm, Δt = 10 ps) refracted through plasma. We report results of the first Nike-GIR measurement on a CH plasma produced by the Nike laser pulse (˜1 ns FWHM) with the intensity of 1.1 × 1015 W/cm2. The measured angles and transmissions were processed to construct spatial profiles of electron density (ne) and temperature (Te) in the underdense coronal region of the plasma. Using an inversion algorithm developed for the strongly refracted rays, the deployed GIR system probed electron densities up to 4 × 1021 cm-3 with the density scale length of 120 μm along the plasma symmetry axis. The resulting ne and Te profiles are verified to be self-consistent with the measured quantities of the refracted probe light.

  7. Observation of scattered light between omega/2 and 3/2 omega in short wavelength laser produced plasmas

    International Nuclear Information System (INIS)

    Goldman, L.M.; Seka, W.; Tanaka, K.; Simon, A.; Short, R.

    1984-01-01

    Extensive measurements have been carried out on scattered radiation in the spectral region between omega/2 and 3/2 omega from plasmas produced by 351 nm lasers. The relative intensities of the continuum radiation relative to the line features at omega/2 and 3/2 omega will be shown. A new spectral feature has been observed between 3/2 omega and omega which may be interpreted as an upscattered component produced by ordinary Raman scattering. The overall experimental evidence for ordinary Raman scattering vs stimulated Raman scattering will be discussed

  8. Spatial coherence properties of a compact and ultrafast laser-produced plasma keV x-ray source

    International Nuclear Information System (INIS)

    Boschetto, D.; Mourou, G.; Rousse, A.; Mordovanakis, A.; Hou, Bixue; Nees, J.; Kumah, D.; Clarke, R.

    2007-01-01

    The authors use Fresnel diffraction from knife-edges to demonstrate the spatial coherence of a tabletop ultrafast x-ray source produced by laser-plasma interaction. Spatial coherence is achieved in the far field by producing micrometer-scale x-ray spot dimensions. The results show an x-ray source size of 6 μm that leads to a transversal coherence length of 20 μm at a distance of 60 cm from the source. Moreover, they show that the source size is limited by the spatial spread of the absorbed laser energy

  9. Experimental studies of particle acceleration with ultra-intense lasers - Applications to nuclear physics experiments involving laser-produced plasmas

    International Nuclear Information System (INIS)

    Plaisir, C.

    2010-11-01

    For the last ten years, the Ultra High Intensity Lasers offer the opportunity to produce accelerated particle beams which contain more than 10 12 electrons, protons accelerated into a few ps. We have simulated and developed some diagnostics based on nuclear activation to characterize both the angular and the energy distributions of the particle beams produced with intense lasers. The characterization methods which are presented are illustrated by means of results obtained in different experiments. We would use the particle beams produced to excite nuclear state in a plasma environment. It can modify intrinsic characteristics of the nuclei such as the half-life of some isomeric states. To prepare this kind of experiments, we have measured the nuclear reaction cross section (gamma,n) to produce the isomeric state of the 84 Rb, which has an excitation energy of 463 keV, with the electron accelerator ELSA of CEA/DIF in Bruyeres-le-Chatel (France). (author)

  10. High-speed interferometry of expanding and collapsing laser produced plasma

    International Nuclear Information System (INIS)

    Basov, N.G.; Boiko, V.A.; Gribkov, V.A.; Zakharov, S.M.; Krokhin, O.N.; Nikulin, V.Ya.; Sklizkov, G.V.

    An installation with a good time and space resolution for the interferometric investigation of dense non-stationary plasma is described. The installation consists of a Mach-Zender interferometer, an electro-optical image converter camera and a ruby laser with an impulse of variable duration of 1nsec to 150nsec

  11. Characteristics of ceramic oxide nanoparticles synthesized using radio frequency produced thermal plasma

    International Nuclear Information System (INIS)

    Dhamale, Gayatri D.; Mathe, V.L.; Bhoraskar, S.V.; Ghorui, S.

    2015-01-01

    Thermal plasma devices with their unique processing capabilities due to extremely high temperature and steep temperature gradient play an important role in synthesis of ultrafine powders in the range of 100nm or less. High temperature gas phase synthesis in Radio Frequency (RF) thermal plasma reactor is an attractive route for mass production of refractory nanoparticles, especially in the case of rare earth oxides. Here we report synthesis of Yttrium Oxide (Y_2O_3), Neodymium Oxide (Nd_2O_3) and Aluminum Oxide (Al_2O_3) in an inductively coupled radio frequency thermal plasma reactor. Synthesized nanoparticles find wide application in various fields like gate dielectrics, photocatalytic applications, laser devices and photonics. Nano sized Yttrium oxide, Neodymium Oxide and Aluminum oxide powders were separately synthesized in an RF plasma reactor starting with micron sized irregular shaped precursor powders. The system was operated at 3MHz in atmospheric pressure at different power levels. Synthesized powders were scrapped out from different deposition locations inside the reactor and characterized for their phase, morphology, particle size, crystallinity and other characteristic features. Highly crystalline nature of the synthesized particles, narrow size distribution, location dependent phase formation, and distinct variation in the inherent defect states compared to the bulk are some of the important characteristic features observed

  12. Two dimensional analytical considerations of large magnetic and electric fields in laser produced plasmas

    International Nuclear Information System (INIS)

    Eliezer, S.; Loeb, A.

    1985-08-01

    A simple model in two dimensions is developed and solved analytically taking into account the electric and magnetic fields in laser procuded plasmas. The electric potential in this model is described by a nonlinear differential equation. The stationary solution of this model is consistent for -0.1 less than or equal to psi 6 v/cm]/[B/MGauss] approx. 1

  13. Recent experiments on the hydrodynamics of laser-produced plasmas conducted at the PALS laboratory

    Czech Academy of Sciences Publication Activity Database

    Batani, D.; Dezulian, R.; Redaelli, R.; Benocci, R.; Stabile, H.; Canova, F.; Desai, T.; Lucchini, G.; Krouský, Eduard; Mašek, Karel; Pfeifer, Miroslav; Skála, Jiří; Dudžák, Roman; Rus, Bedřich; Ullschmied, Jiří; Malka, V.; Fauré, J.; Koenig, M.; Limpouch, J.; Nazarov, W.; Pepler, D.; Nagai, K.; Norimatsu, T.; Nishimura, H.

    2007-01-01

    Roč. 25, - (2007), s. 127-141 ISSN 0263-0346 R&D Projects: GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z10100523; CEZ:AV0Z20430508 Keywords : equation of state * laboratory astrophysics * plasma hydrodynamics * shock acceleration * pressure * smoothing. Subject RIV: BH - Optics, Masers, Lasers Impact factor: 4.696, year: 2007

  14. Coherent bremsstrahlung generation of harmonics in a laser-produced plasma

    International Nuclear Information System (INIS)

    Silin, Viktor P

    1999-01-01

    Foundations of a theory of generation of the harmonics of a laser pump in a fully ionised plasma are proposed. This theory makes it possible to describe the relationships governing harmonic generation in an analytical form. For an elliptically polarised pump field with a low degree of circular polarisation A, the range of plasma parameters is established in which the number of harmonics is found to be of the order of A -1 . Anomalous polarisation properties of the harmonics are predicted. In this case, their polarisation is seen to be nearly perpendicular to the pump polarisation and the degree of circular polarisation increases with the harmonic order number. The harmonic-order-dependent intensity of the pump field which results in circular polarisation of a harmonic is determined making allowance for thermal plasma motion. The conditions under which increasing the low degree of circular pump polarisation increases the efficiency of harmonic generation are established. The nonlinear dependence of the pump polarisation on its intensity under the conditions of collisional absorption in a plasma are identified and an instability of the circular polarisation is revealed. For a plane-polarised pump, it is shown how the maximum power of a harmonic and the pump power corresponding to this maximum scale up with the harmonic order number. The conditions under which the number of harmonics generated is limited owing to the relativistic nature of electron motion in the pump field are established. This effect appears for an unexpectedly weak relativity. (invited paper)

  15. Initial results of strand produced in Phase 2 of the SSCL Vendor Qualification Program

    International Nuclear Information System (INIS)

    Erdmann, M.; Capone, D. II; Coleman, S.; Jones, B.; Seuntjens, J.

    1993-05-01

    In 1991, the Superconducting Super Collider Laboratory (SSCL) instituted a program to qualify specific superconductor manufacturers for production of cable acceptable for use in both Collider Dipole (CDM) and Quadrupole (CQM) magnets. The SSCL Vendor Qualification Program (VQP) was designed with two Phases. Phase 1 was divided into two additional phases, 1A and 1B, which ran concurrently. In Phase 1B, each vendor was directed to manufacture roughly 3000 kg of cable using a ''baseline'' process. The baseline process was agreed to by both the SSCL and the vendor at the beginning of the VQP. In this phase, process control was closely monitored with the use of statistical methods and each vendor was graded based on these results. Phase 1A, known as the R ampersand D phase, was developed to allow each vendor an opportunity to optimize and improve on their baseline process in terms of both cost and manufacturability. In this phase, multifilament billets were designed to explore several key variables such as alternate alloy sources, process modifications and improved billet designs. At the end of Phase 1, the results from both 1A and 1B were evaluated at a review between the SSCL and each vendor, and a final Phase 2 process was generated and fixed using the best results. In Phase 2, each vendor is required to manufacture roughly 6000 kg of superconducting cable under a firm fixed price contract which can then be used to create an accurate price estimate for competitive bidding on the full rate production CDM and CQM contracts. At the end of Phase 2, each vendor must meet the minimum requirements outlined in the contract to become a qualified superconducting cable supplier. For one requirement, critical process variables identified by the SSCL Conductor Department at the beginning of the VQP will be evaluated to determine the quality and uniformity of the material produced during Phase 2 of the program

  16. Plasma Assisted Ignition and Combustion at Low Initial Gas Temperatures: Development of Kinetic Mechanism

    Science.gov (United States)

    2016-10-05

    R and Pouvesle J M 2009 Experimental study of a compact nanosecond plasma gun Plasma Processes and Polymers 6 795—802 [11] Heinlin J, Morfill G...radially symmetrical geometry. The thickness of the plasma layer in the direction perpendicular to the dielectric plane is about 1 mm. The central coaxial ...Positive and negative polarity discharge at elevated pres- sures Discharge in coaxial geometry has been developed for plasma assisted ignition at high

  17. Chronological study of beryllium plasma produced by a laser beam; Etude chronologique du plasma de beryllium cree par le faisceau d'un laser

    Energy Technology Data Exchange (ETDEWEB)

    Langer, Ph; Tonon, G; Durand, Y; Buges, J C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-07-01

    We have carried out several investigations (ultrafast cinematography, visible and ultra-violet spectroscopy, interferometry, charged particle detection) on beryllium plasma produced by a ruby laser having a maximum power of 9 x 10{sup 10} watt/cm{sup 2} at the focal point of an objective with a 6,7 cm focal length. The common characteristic of all these investigations is a time resolution which is sufficient to follow changes in the plasma during the entire duration of the laser pulse. The plasma visible from - 60 ns (time zero corresponds to the top of the laser pulse) undergoes an uniform acceleration from - 30 to + 5 nanoseconds; at this moment its velocity reaches a value of 10{sup 7} cm/sec. Be{sup +}, Be{sup 2+} and Be{sup 3+} ions (corresponding to an ionisation potential of 153 eV) are emitted by the plasma as soon as it is formed and have a maximum kinetic energy of 1500 eV. The spectroscopic study of the plasma has shown the appearance of recombination lines of ionized beryllium and of lines of excited beryllium at + 70 nanoseconds and + 120 nanoseconds respectively. These lines are still visible after + 470 and + 720 nanoseconds. Interferometric measurements carried out on this plasma have shown that its electronic density is not uniform and decreases rapidly at increasing distance from the target. For example at 0.3 mm from the surface of the target the density becomes equal to 2.3 x 10{sup 18} e/cm{sup 3} and 5.5 x 10{sup 17} e/cm{sup 3} at + 20 and + 40 nanoseconds respectively. (authors) [French] Nous avons effectue plusieurs diagnostics (cinematographie ultra-rapide, spectroscopie dans le visible et dans l'ultraviolet, interferometrie, detection de particules chargees) sur le plasma de beryllium engendre par un laser a rubis delivrent au foyer d'un objectif de distance focale 6,7 cm un eclairement maximum de 9. 10{sup 10} W/cm{sup 2}. La caracteristique commune a tous ces diagnostics est une resolution temporelle suffisante qui nous permet de suivre

  18. Diffusion-controlled regime of surface-wave-produced plasmas in helium gas

    International Nuclear Information System (INIS)

    Berndt, J; Makasheva, K; Schlueter, H; Shivarova, A

    2002-01-01

    The study presents a numerical fluid-plasma model of diffusion-controlled surface-wave-sustained discharges in helium gas. The self-consistent behaviour of the discharge based on the interrelation between plasma density and Θ, the power absorbed on average by one electron, is described. The nonlinear process of step ionization in the charged particle balance equation is the main factor, which ensures the self-consistency. However, it is shown that in helium discharges, the ionization frequencies enter the dependence of Θ on the plasma density also through the ambipolar-diffusion coefficient. Results at two different values of the gas pressure and of the wave frequency are discussed. The lower value of the gas pressure is chosen according to the condition to have a pure diffusion-controlled regime without interference with a transition to the free-fall regime. The boundary condition for the ion flux at the wall sheath is used for determination of the value of μ, the quantity denoting the degree of the radial plasma-density inhomogeneity which, together with the electron-neutral elastic collision frequency, influences the wave propagation characteristics. The two values of the wave frequency chosen provide descriptions of high-frequency and microwave discharges. The model results in the self-consistent structure of the discharge: interrelated variations along the discharge length of wavenumber, space damping rate, Θ, plasma density and electron temperature. The power necessary for sustaining discharges of a given length is also calculated. Comparisons with argon discharges are shown

  19. Application of laser-produced-plasmas to determination of carbon content in steel; Aplicacion de los plasmas generados por laser a la determinacion de carbono en aceros

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, M; Aragon, C; Aguilera, J A; Campos, J

    1994-07-01

    This paper describes an analytical method to determine carbon content in solid and molten steel. It is based on the study of the emission spectrum from a Nd-YAG laser produced plasma. The light emitted from the plasma is focused to the entrance slit of a spectrometer and detected by an OMA III system. For every laser pulse an spectral range of 100 A are recorded. With the use of time-resolved spectroscopy a precision of 1.6 % and a detection limit of 65 ppm of carbon content in steel have been obtained. These values are similar to those of other accurate conventional techniques but using optics fiber and laser excitation it is possible to made sample calibrations in hostile environments. Also, as the analysis are made in real time changes in sample composition can be measured without stopping production processes. (Author) 26 refs.

  20. Multiple solutions in the theory of direct current glow discharges: Effect of plasma chemistry and nonlocality, different plasma-producing gases, and 3D modelling

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, P. G. C.; Benilov, M. S. [Departamento de Física, CCCEE, Universidade da Madeira, Largo do Município, 9000 Funchal (Portugal)

    2013-10-15

    The work is aimed at advancing the multiple steady-state solutions that have been found recently in the theory of direct current (DC) glow discharges. It is shown that an account of detailed plasma chemistry and non-locality of electron transport and kinetic coefficients results in an increase of the number of multiple solutions but does not change their pattern. Multiple solutions are shown to exist for discharges in argon and helium provided that discharge pressure is high enough. This result indicates that self-organization in DC glow microdischarges can be observed not only in xenon, which has been the case until recently, but also in other plasma-producing gases; a conclusion that has been confirmed by recent experiments. Existence of secondary bifurcations can explain why patterns of spots grouped in concentric rings, observed in the experiment, possess in many cases higher number of spots in outer rings than in inner ones.

  1. Sharpening of the 6.8 nm peak in an Nd:YAG laser produced Gd plasma by using a pre-formed plasma

    Directory of Open Access Journals (Sweden)

    Yong Tian

    2016-03-01

    Full Text Available For effective use of a laser-produced-plasma (LPP light source, an LPP is desired to emit a narrow spectral peak because the reflection spectrum of multilayer mirrors for guiding emission from the source is very narrow. While a Gd plasma has been studied extensively as an extreme ultraviolet (EUV light source at around 6.8 nm, where La/B4C multilayer is reported to have a high reflectivity with a bandwidth of about 0.6 %, all previous works using an Nd:YAG laser reported very broad spectra. This paper reports the first narrowing of the 6.8 nm peak in the case of using an Nd:YAG laser to generate a Gd plasma by using a pre-pulse. The best peak narrowing is observed when a pre-formed plasma is heated by a 1064 nm main laser pulse with a duration of 10 ns at the irradiation density of 4x 1011 W/cm2 at a delay time of 50 ns after the pre-pulse irradiation. The observed spectral width of about 0.3 nm is about one fifth of the value for no pre-formed plasma. The peak wavelength of the 6.8 nm band shifted to a longer wavelength side and the peak was broadened both for lower and higher laser irradiation density. It is discussed that this robustness of the peak position of the 6.8 nm Gd peak against temperature change is suitable to achieve a narrow bandwidth from an LPP generated on solid. The observed spectra are compared with those previously reported in various conditions.

  2. Parametric study of plasma-mediated thermoluminescence produced by Al2O3 sub-micron powders

    Science.gov (United States)

    Morávek, T.; Ambrico, P. F.; Ambrico, M.; Schiavulli, L.; Ráheľ, J.

    2017-10-01

    Sub-micron Al2O3 powders with a surface activated by dielectric barrier discharge exhibit improved performance in wet deposition of ceramic layers. In addressing the possible mechanisms responsible for the observed improvement, a comprehensive thermoluminescence (TL) study of plasma-activated powders was performed. TL offers the unique possibility of exploring the population of intrinsic electrons/holes in the charge trapping states. This study covers a wide range of experimental conditions affecting the TL of powders: treatment time, plasma working gas composition, change of discharge configuration, step-annealing of powder, exposure to laser irradiation and aging time. Deconvoluted TL spectra were followed for the changes in their relative contributions. The TL spectra of all tested gases (air, Ar, N2 and 5% He in N2) consist of the well-known main dosimetric peak at 450 K and a peak of similar magnitude at higher temperatures, centered between 700 and 800 K depending on the working gas used. N2 plasma treatment gave rise to a new specific TL peak at 510 K, which exhibited several peculiarities. Initial thermal annealing of Al2O3 powders led to its significant amplification (unlike the other peaks); the peak was insensitive to optical bleaching, and it exhibited slow gradual growth during the long-term aging test. Besides its relevance to the ceramic processing studies, a comprehensive set of data is presented that provides a useful and unconventional view on plasma-mediated material changes.

  3. Picosecond streak camera diagnostics of CO2 laser-produced plasmas

    International Nuclear Information System (INIS)

    Jaanimagi, P.A.; Marjoribanks, R.S.; Sancton, R.W.; Enright, G.D.; Richardson, M.C.

    1979-01-01

    The interaction of intense laser radiation with solid targets is currently of considerable interest in laser fusion studies. Its understanding requires temporal knowledge of both laser and plasma parameters on a picosecond time scale. In this paper we describe the progress we have recently made in analysing, with picosecond time resolution, various features of intense nanosecond CO 2 laser pulse interaction experiments. An infrared upconversion scheme, having linear response and <20 ps temporal resolution, has been utilized to characterise the 10 μm laser pulse. Various features of the interaction have been studied with the aid of picosecond IR and x-ray streak cameras. These include the temporal and spatial characteristics of high harmonic emission from the plasma, and the temporal development of the x-ray continuum spectrum. (author)

  4. Time-resolved x-ray line diagnostics of laser-produced plasmas

    International Nuclear Information System (INIS)

    Kauffman, R.L.; Matthews, D.L.; Kilkenny, J.D.; Lee, R.W.

    1982-11-01

    We have examined the underdense plasma conditions of laser irradiated disks using K x-rays from highly ionized ions. A 900 ps laser pulse of 0.532 μm light is used to irradiate various Z disks which have been doped with low concentrations of tracer materials. The tracers, whose Z's range from 13 to 22, are chosen so that their K x-ray spectrum is sensitive to typical underdense plasma temperatures and densities. Spectra are measured using a time-resolved crystal spectrograph recording the time history of the x-ray spectrum. A spatially-resolved, time-integrated crystal spectrograph also monitors the x-ray lines. Large differences in Al spectra are observed when the host plasms is changed from SiO 2 to PbO or In. Spectra will be presented along with preliminary analysis of the data

  5. Twined plasma produced by powered double probe in the tail region

    International Nuclear Information System (INIS)

    Minami, Sigeyuki; Takeya, Yoshio; Hirose, Yoshiaki.

    1977-01-01

    Simulation experiments have been operated by some workers in order to make clear the behavior of plasma in the magnetosphere. The large-scales surveys of the upper atmosphere with the use of satellite were not done in those days, so this simulated magnetospheric experiments in the laboratory was watched. These early experiments were done in order to know the structure of the shock front and its time variation at the front of the earth which was generated by the interaction of the high speed plasma flow and magnetic dipole, and also to know the magnetic field distribution in the solar cusp near the shock front. At this paper, the results obtained by optical method for the behavior and the structures in the region at tail of the magnetosphere are dealed. In order to know the tail region, active power source of named powered double probe is used. (auth.)

  6. Non local-thermodynamical-equilibrium effects in the simulation of laser-produced plasmas

    Science.gov (United States)

    Klapisch, M.; Bar-Shalom, A.; Oreg, J.; Colombant, D.

    1998-05-01

    Local thermodynamic equilibrium (LTE) breaks down in directly or indirectly driven laser plasmas because of sharp gradients, energy deposition, etc. For modeling non-LTE effects in hydrodynamical simulations, Busquet's model [Phys. Fluids B 5, 4191 (1993)] is very convenient and efficient. It uses off-line generated LTE opacities and equation of states via an effective, radiation-dependent ionization temperature Tz. An overview of the model is given. The results are compared with an elaborate collisional radiative model based on superconfigurations. The agreements for average charge Z* and opacities are surprisingly good, even more so when the plasma is immersed in a radiation field. Some remaining discrepancy at low density is attributed to dielectronic recombination. Improvement appears possible, especially for emissivities, because the concept of ionization temperature seems to be validated.

  7. Non local-thermodynamical-equilibrium effects in the simulation of laser-produced plasmas

    International Nuclear Information System (INIS)

    Klapisch, M.; Bar-Shalom, A.; Oreg, J.; Colombant, D.

    1998-01-01

    Local thermodynamic equilibrium (LTE) breaks down in directly or indirectly driven laser plasmas because of sharp gradients, energy deposition, etc. For modeling non-LTE effects in hydrodynamical simulations, Busquet close-quote s model [Phys. Fluids B 5, 4191 (1993)] is very convenient and efficient. It uses off-line generated LTE opacities and equation of states via an effective, radiation-dependent ionization temperature T z . An overview of the model is given. The results are compared with an elaborate collisional radiative model based on superconfigurations. The agreements for average charge Z * and opacities are surprisingly good, even more so when the plasma is immersed in a radiation field. Some remaining discrepancy at low density is attributed to dielectronic recombination. Improvement appears possible, especially for emissivities, because the concept of ionization temperature seems to be validated. copyright 1998 American Institute of Physics

  8. Electron transport phenomena and dense plasmas produced by ultra-short pulse laser interaction

    International Nuclear Information System (INIS)

    More, R.M.

    1994-01-01

    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

  9. Porous Nb-Ti based alloy produced from plasma spheroidized powder

    OpenAIRE

    Li, Qijun; Zhang, Lin; Wei, Dongbin; Ren, Shubin; Qu, Xuanhui

    2017-01-01

    Spherical Nb-Ti based alloy powder was prepared by the combination of plasma spheroidization and mechanical alloying. Phase constituents, microstructure and surface state of the powder, and pore characteristics of the resulting porous alloy were investigated. The results show that the undissolved W and V in the mechanically alloyed powder is fully alloyed after spheroidization, and single β phase is achieved. Particle size of the spheroidized powder is in the range of 20–110 μm. With the decr...

  10. Self-absorption influence on the optical spectroscopy of zinc oxide laser produced plasma

    Energy Technology Data Exchange (ETDEWEB)

    De Posada, E; Arronte, M A; Ponce, L; Rodriguez, E; Flores, T [Centro de Investigacion en Ciencia Aplicada y TecnologIa Avanzada-Unidad Altamira, Tamaulipas (Mexico); Lunney, J G, E-mail: edeposada@ipn.mx [School of Physics, Trinity College Dublin (Ireland)

    2011-01-01

    Optical spectroscopy is used to study the laser ablation process of ZnO targets. It is demonstrated that even if Partial Local Thermal Equilibrium is present, self absorption process leads to a decrease of recorded lines emission intensities and have to be taken into account to obtain correct values of such parameters. It is presented a method that combines results of both Langmuir probe technique and Anisimov model to obtain correct values of plasma parameters.

  11. Recombination of a fast expanding plasma

    International Nuclear Information System (INIS)

    Salvat, M.

    1979-05-01

    The goal of the following calculations is to determine numerically the recombination of dense plasmas (for instance of laser-produced plasmas). The recombination is computed for plasmas with initial densities of 10 24 27 [m -3 ] and with initial temperatures >= 50 eV. The ionization of the plasma remains essentially constant during the early phase of expansion. The time for which the ionization is 'frozen-in' grows with decreasing initial density and with increasing initial temperature. (orig.) [de

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

    Directory of Open Access Journals (Sweden)

    Gilberto Petraconi

    2010-04-01

    Full Text Available 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 exposure time under various temperatures on the sample surface. A microscopic analysis was then carried out for the study of microscopic aspects of the erosion of material surface. These experiments showed that the mass loss per unit area is approximately proportional to the exposure time and strongly depends on the temperature of the material surface. The mass erosion rate of graphite was appreciably higher than the C/C composite. The ablation rate in the carbon matrix region in C/C composite was also noticeably higher than that in the fiber region. In addition, the latter varied according to the orientation of fibers relatively to the flow direction. These tests indicated an excellent ablation resistance of the C/C composite, thus being a reliable material for rocket nozzles and heat shielding elements of the protection systems of hypersonic apparatuses from aerodynamic heating.

  13. Effect of Ponderomotive Terms on Heat Flux in Laser-Produced Plasmas

    Science.gov (United States)

    Li, G.

    2005-10-01

    A laser electromagnetic field introduces ponderomotive termsootnotetextV. N. Goncharov and G. Li, Phys. Plasmas 11, 5680 (2004). in the heat flux in a plasma. To account for the nonlocal effects in the ponderomotive terms, first, the kinetic equation coupled with the Maxwell equations is numerically solved for the isotropic part of the electron distribution function. Such an equation includes self-consistent electromagnetic fields and laser absorption through the inverse bremsstrahlung. Then, the anisotropic part is found by solving a simplified Fokker--Planck equation. Using the distribution function, the electric current and heat flux are obtained and substituted into the hydrocode LILAC to simulate ICF implosions. The simulation results are compared against the existing nonlocal electron conduction modelsootnotetextG. P. Schurtz, P. D. Nicola"i, and M. Busquet, Phys. Plasmas 9, 4238 (2000). and Fokker--Planck simulations. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-92SF19460.

  14. Broadening of hydrogenic X rays emitted by a laser-produced plasma

    International Nuclear Information System (INIS)

    Nguyen, Hoe; Grumberg, J.; Caby, M.; Leboucher, E.; Coulaud, G.

    1980-01-01

    This study is devoted to X-rays broadened by laser impact or implosion. In addition to usual broadening processes due to the high and low components of plasma microfield, we have examined the influence of the self-generated magnetic field B which is correlated to the Doppler effect by the motional electric field. Concerning the interaction between plasma electrons and radiating ions with high charge number Zsub(E), it is shown that the curvature of electron trajectories must be taken into account in the broadening operator calculation. The influence of this curvature consists in reducing the contribution of dipolar interaction and enhancing the contribution of multipolar interactions with higher order. As a particular consequence on the half-width of Lyman-α-lines we have found values ten times larger than those obtained from the usual dipolar approximation. In the other hand, spectral lines emitted from the plasma critical region exhibits a strong self-generated magnetic field effect. Principally, it consists in polarizing the spectral profiles and introducing a large dependence with respect to the observation direction k. Particularly, profiles observed in the direction parallel to the magnetic field exhibit a deep central minimum which must be taken into account in a quantitative study of the line absorption properties [fr

  15. Study of the properties of the operation of an end-type plasma accelerator initiated by electric foil detonation

    International Nuclear Information System (INIS)

    Gol'dberg, M.M.; Vikaruk, A.Ya.; Sokolov, S.V.; Suminov, I.V.

    1986-01-01

    The results of experimental study of an end-type high-current pulsed plasma accelerator initiated by electric foil detonation are presented. The development stages of the process and formation of the flow pinch are examined during accelerator operation. Analytic functions are obtained which determine the origination conditions of the pinch-effect

  16. Transition probabilities for lines of Cr II, Na II and Sb I by laser produced plasma atomic emission spectroscopy

    International Nuclear Information System (INIS)

    Gonzalez, A. M.; Ortiz, M.; Campos, J.

    1995-01-01

    Absolute transition probabilities for lines of CR II, Na II and Sb I were determined by emission spectroscopy of laser induced plasmas. the plasma was produced focusing the emission of a pulsed Nd-Yag laser on solid samples containing the atom in study. the light arising from the plasma region was collected by and spectrometer. the detector used was a time-resolved optical multichannel analyzer (OMA III EG and G). The wavelengths of the measured transitions range from 2000 sto 4100 A. The spectral resolution of the system was 0. 2 A. The method can be used in insulators materials as Cl Na crystals and in metallic samples as Al-Cr and Sn-Sn alloys. to avoid self-absorption effects the alloys were made with low Sb or Cr content. Relative transition probabilities have been determined from measurements of emission-line intensities and were placed on an absolute scale by using, where possible, accurate experimental lifetime values form the literature or theoretical data. From these measurements, values for plasma temperature (8000-24000 K), electron densities (∼∼ 10''16 cm ''-3) and self-absorption coefficients have been obtained. (Author) 56 refs

  17. Transition probabilities for lines of Cr II, Na II and Sb I by laser produced plasma atomic emission spectroscopy

    International Nuclear Information System (INIS)

    Gonzalez, A.M.; Ortiz, M.; Campos, J.

    1995-09-01

    Absolute transition probabilities for lines of Cr II, Na II and Sb I were determined by emission spectroscopy of laser induced plasmas. The plasma was produced focusing the emission of a pulsed Nd-Yag laser on solid samples containing the atom in study. The light arising from the plasma region was collected by and spectrometer. the detector used was a time-resolved optical multichannel analyzer (OMA III EG and G). The wavelengths of the measured transitions range from 2000 to 4100 A. The spectral resolution of the system was 0.2 A. The method can be used in insulators materials as Cl Na crystals and in metallic samples as Al-Cr and Sn-Sb alloys. To avoid self-absorption effects the alloys were made with low Sb or Cr content. Relative transition probabilities have been determined from measurements of emission-line intensities and were placed on an absolute scale by using, where possible, accurate experimental lifetime values form the literature or theoretical data. From these measurements, values for plasma temperature (8000-24000K), electron densities (approx 10 ''16 cm''-3) and self-absorption coefficients have been obtained

  18. Properties of laser-produced GaAs plasmas measured from highly resolved X-ray line shapes and ratios

    Science.gov (United States)

    Seely, J. F.; Fein, J.; Manuel, M.; Keiter, P.; Drake, P.; Kuranz, C.; Belancourt, Patrick; Ralchenko, Yu.; Hudson, L.; Feldman, U.

    2018-03-01

    The properties of hot, dense plasmas generated by the irradiation of GaAs targets by the Titan laser at Lawrence Livermore National Laboratory were determined by the analysis of high resolution K shell spectra in the 9 keV to 11 keV range. The laser parameters, such as relatively long pulse duration and large focal spot, were chosen to produce a steady-state plasma with minimal edge gradients, and the time-integrated spectra were compared to non-LTE steady state spectrum simulations using the FLYCHK and NOMAD codes. The bulk plasma streaming velocity was measured from the energy shifts of the Ga He-like transitions and Li-like dielectronic satellites. The electron density and the electron energy distribution, both the thermal and the hot non-thermal components, were determined from the spectral line ratios. After accounting for the spectral line broadening contributions, the plasma turbulent motion was measured from the residual line widths. The ionization balance was determined from the ratios of the He-like through F-like spectral features. The detailed comparison of the experimental Ga spectrum and the spectrum simulated by the FLYCHK code indicates two significant discrepancies, the transition energy of a Li-like dielectronic satellite (designated t) and the calculated intensity of a He-like line (x), that should lead to improvements in the kinetics codes used to simulate the X-ray spectra from highly-charged ions.

  19. Unresolved transition array based water window soft x-ray source by laser-produced high-Z plasma

    International Nuclear Information System (INIS)

    Higashiguchi, Takeshi; Dunne, Padraig; O'Sullivan, Gerry

    2013-01-01

    We demonstrate a table-top broadband emission water window source based on laser-produced high-Z plasmas. resonance emission from multiply charged ions merges to produce intense unresolved transition arrays (UTAs) in the 2 to 4 nm region, extending below the carbon K edge (4.37 nm). Arrays resulting from n=4-n=4 transitions are overlaid with n=4-n=5 emission and shift to shorter wavelength with increasing atomic number. An outline of a microscope design for single-shot live cell imaging is proposed based on a bismuth plasma UTA source, coupled to multilayer mirror optics. At power densities available from 'table-top' solid-state lasers, comparison of emission from a number of targets has shown that 3d-4f UTA in zirconium plasmas have highest overall brightness and in an imaging system based on reflective multilayer mirrors, may, depending on bandwidth, have superior performance than either line or broader-band sources. (author)

  20. Influence of micro- and macro-processes on the high-order harmonic generation in laser-produced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ganeev, R. A., E-mail: rashid-ganeev@mail.ru [Ophthalmology and Advanced Laser Medical Center, Saitama Medical University, 38 Morohongo, Moroyama-machi, Iruma-gun, Saitama 350-0495 (Japan); Physical Department, Voronezh State University, Voronezh 394006 (Russian Federation)

    2016-03-21

    We compare the resonance-induced enhancement of single harmonic and the quasi-phase-matching-induced enhancement of the group of harmonics during propagation of the tunable mid-infrared femtosecond pulses through the perforated laser-produced indium plasma. We show that the enhancement of harmonics using the macro-process of quasi-phase-matching is comparable with the one using micro-process of resonantly enhanced harmonic. These studies show that joint implementation of the two methods of the increase of harmonic yield could be a useful tool for generation of strong short-wavelength radiation in different spectral regions. We compare these effects in indium, as well as in other plasmas.

  1. Anisotropic instability of the photoelectrons generated by soft x-ray radiation of the laser-produced plasma focus

    International Nuclear Information System (INIS)

    Klumov, B.A.; Tarakanov, V.P.

    1994-01-01

    The electron field with the anisotropic distribution function is being formed when the gas is being affected with ionizing radiation. The anisotropy of the distribution function occurs due to the fact that photoelectrons fly mainly in the direction perpendicular to that of ionizing radiation quantum propagation. In order to emphasize the most typical features of the developed anisotropic instability, photoelectrons were believed to fly strictly across the photon propagation direction. Two-dimensional electromagnetic particle simulations have been carried out to study high-frequency disturbances in the plasma produced by ionizing radiation. Elastic processes were taken into account. It has been shown, in particular, that the energy of anisotropic electrons transforms mainly into that of magnetic pulsations (approximately 7% of the energy transforms into that of magnetic pulsations). Development of the anisotropic instability result in a space stratification into current filaments. The anisotropic instability study can be important for an interpretation of electromagnetic emission spectra for a plasma disturbed by radiation

  2. Observation of dielectronic satellites in the K-spectrum of argon ions in plasma produced by femtosecond laser pulses

    International Nuclear Information System (INIS)

    Magunov, A.I.; Faenov, A.Ya.; Skobelev, I.Yu.; Pikuz, T.A.; Biemont, E.; Quinet, P.; Blasco, F.; Bonte, C.; Dorchies, F.; Caillaud, T.; Salin, F.; Stenz, C.

    2002-01-01

    The satellite structure of 1s2p 1,3 P 1 -1s 21 S 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 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 simulated with the use of the spectroscopic data for the AISs of multicharged ions obtained within the multiconfiguration relativistic Hartree-Fock method. Good agreement with experimental data is obtained when the main population channels of these states are taken into account for typical values of cluster-target plasma parameters

  3. Development of procedure using plasma welding process to produce 125I seeds

    International Nuclear Information System (INIS)

    Feher, Anselmo

    2006-01-01

    The prostate cancer, which is the second cause of death by cancer in men, overcome only by lung cancer, is a problem of public health in Brazil. Brachytherapy is among the possible available treatments for prostate cancer, in which small seeds containing 125 I radioisotope are implanted in the prostate. The seed consists of a titanium sealed capsule with 0.8 mm external diameter and 4.5 mm length, containing a central silver wire with adsorbed 125 I. The plasma arc welding is one of the viable techniques for the sealing process. The equipment used in this technique is less costly than in other processes. The main objective of this work was the development and the validation of the welding procedure using plasma welding process and the elaboration of a sealing routine according to Good Manufacturing Practices. The development of this work has presented the following phases: cut and cleaning of the titanium material, determination of the welding parameters, development of a device for holding the titanium tube during the welding process, validation of sealed sources according to ISO 2919 Sealed Radioactive Sources - General Requirements and Classification, leakage test according to ISO 9978 Sealed Radioactive Sources - Leakage Test Methods and metallographic assays. The developed procedure, to seal 125 I seeds using plasma welding process, has shown to be efficient, satisfying all the established requirements of ISO 2919. The results obtained in this work have given the possibility to establish a routine production process according to the orientations presented in resolution RDC number 59 - Good Manufacturing Practices do Medical Products of the ANVISA - Brazilian Nacional Agency of Sanitary Surveillance. (author)

  4. Vacuum laser-produced plasma for analytical application in fusion technologies

    International Nuclear Information System (INIS)

    Almaviva, S; Caneve, L; Colao, F; Fantoni, R; Maddaluno, G

    2012-01-01

    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.

  5. Supersonic Ionization Wave Driven by Radiation Transport in a Short-Pulse Laser-Produced Plasma

    International Nuclear Information System (INIS)

    Ditmire, T.; Gumbrell, E.T.; Smith, R.A.; Mountford, L.; Hutchinson, M.H.

    1996-01-01

    Through the use of an ultrashort (2ps) optical probe, we have time resolved the propagation of an ionization wave into solid fused silica. This ionization wave results when a plasma is created by the intense irradiation of a solid target with a 2ps laser pulse. We find that the velocity of the ionization wave is consistent with radiation driven thermal transport, exceeding the velocity expected from simple electron thermal conduction by nearly an order of magnitude. copyright 1996 The American Physical Society

  6. Analysis of processes participating during intense iodine-laser-beam interactions with laser-produced plasmas

    Czech Academy of Sciences Publication Activity Database

    Láska, Leoš; Badziak, J.; Jungwirth, Karel; Kalal, M.; Krása, Josef; Krouský, Eduard; Kubeš, P.; Margarone, Daniele; Parys, P.; Pfeifer, Miroslav; Rohlena, Karel; Rosinski, M.; Ryč, L.; Skála, Jiří; Torrisi, L.; Ullschmied, Jiří; Velyhan, Andriy; Wolowski, J.

    2010-01-01

    Roč. 165, 6-10 (2010), s. 463-471 ISSN 1042-0150 R&D Projects: GA MŠk(CZ) LC528; GA AV ČR IAA100100715 EU Projects: European Commission(XE) 228334 - LASERLAB-EUROPE Institutional research plan: CEZ:AV0Z10100523; CEZ:AV0Z20430508 Keywords : laser plasma * non-linear processes * magnetic self-focusing * pinching Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.660, year: 2010

  7. Review of x-ray spectroscopy from laser-produced plasmas

    International Nuclear Information System (INIS)

    Kauffman, R.L.

    1987-09-01

    Recent progress in x-ray spectroscopy from laser plasmas is reviewed. Advances in the use of K-shell spectra as a diagnostic tool is discussed. Much activity in understanding complex spectra especially from Ne I and Ni I isoelectronic series have been made. Much of the progress has been due to observation of amplification from Δn = O transitions from these configurations. The spectroscopy will be discussed and examples of spectra of the amplified lines will be shown. Finally, recent work on using x-ray spectroscopy to diagnose high density implosions will be discussed. 33 refs

  8. Picosecond high power laser systems and picosecond diagnostic technique in laser produced plasma

    International Nuclear Information System (INIS)

    Kuroda, Hiroto; Masuko, H.; Maekawa, Shigeru; Suzuki, Yoshiji; Sugiyama, Masaru.

    1979-01-01

    Highly repetitive, high power YAG and Glass laser systems have been developed and been successfully used for the studies of laser-plasma interactions. Various picosecond diagnostic techniques have been developed for such purposes in the regions from optical to X-ray frequency. Recently highly sensitive X-ray (1 - 10 KeV) streak camera for highly repetitive operations have been developed. Preliminary experiment shows the achievement of 28ps temporal resolution (100μm slit) and good sensitivity with detectable minimum number of 10E3-1KeV photons/shot/slit area. (author)

  9. Photoconductive Detectors with Fast Temporal Response for Laser Produced Plasma Experiments

    International Nuclear Information System (INIS)

    M. J. May; C. Halvorson; T. Perry; F. Weber; P. Young; C. Silbernagel

    2008-01-01

    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 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

  10. Soft x-ray microradiography and lithograph using a laser produced plasma source

    International Nuclear Information System (INIS)

    Cheng, P.C.

    1992-01-01

    Considering the hardware characteristics of the laser-induced plasma X-ray source and the limitations of the conventional cone-beam reconstruction algorithm, a general cone-beam reconstruction algorithm has been developed at our laboratory, in which the motion locus of the X-ray source is an arbitrary curve corresponding to at least a 2π continuous horizontal angular displacement in the coordinate system of the specimen. The preliminary simulation shows that the general cone-beam reconstruction algorithm consistently results in visually satisfactory images

  11. Solid oxide fuel cell electrolytes produced via very low pressure suspension plasma spray and electrophoretic deposition

    Science.gov (United States)

    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

  12. An EPR spin-probe and spin-trap study of the free radicals produced by plant plasma membranes

    Directory of Open Access Journals (Sweden)

    GORAN BACIC

    2005-02-01

    Full Text Available Plant plasma membranes are known to produce superoxide radicals, while the production of hydroxyl radical is thought to occur only in the cell wall. In this work it was demonstrated using combined spin-trap and spin-probe EPR spectroscopic techniques, that plant plasma membranes do produce superoxide and hydroxyl radicals but by kinetically different mechanisms. The results show that superoxide and hydroxyl radicals can be detected by DMPO spin-trap and that the mechanisms and location of their production can be differentiated using the reduction of spin-probes Tempone and 7-DS. It was shown that the mechanism of production of oxygen reactive species is NADH dependent and diphenylene iodonium inhibited. The kinetics of the reduction of Tempone, combined with scavengers or the absence of NADH indicates that hydroxyl radicals are produced by a mechanism independent of that of superoxide production. It was shown that a combination of the spin-probe and spin-trap technique can be used in free radical studies of biological systems, with a number of advantages inherent to them.

  13. Polyurethane coating with thin polymer films produced by plasma polymerization of diglyme

    International Nuclear Information System (INIS)

    Ribeiro, M A; Ramos, A S; Manfredini, M I; Alves, H A; Ramos, E C T; Honda, R Y; Kostov, K G; Lucena, E F; Mota, R P; Algatti, M A; Kayama, M E

    2009-01-01

    Aqueous-based polyurethane dispersions have been widely utilized as lubricants in textile, shoes, automotive, biomaterial and many other industries because they are less aggressive to surrounding environment. In this work thin films with different thickness were deposited on biocompatible polyurethane by plasma polymerization process using diethylene glycol dimethyl ether (Diglyme) as monomer. Molecular structure of the films was analyzed by Fourier Transform Infrared spectroscopy. The spectra exhibited absorption bands of O-H (3500-3200cm -1 ), C-H (3000-2900cm -1 ), C=O (1730-1650cm -1 ), C-O and C-O-C bonds at 1200-1600cm -1 . The samples wettability was evaluated by measurements of contact angle using different liquids such as water, glycerol, poly-ethane and CMC. The polyurethane surface showed hydrophilic behavior after diglyme plasma-deposition with contact angle dropping from 85 deg. to 22 deg. Scanning Electron Microscopy revealed that diglyme films covered uniformly the polyurethane surfaces ensuring to it a biocompatible characteristic.

  14. Time-resolved Thomson scattering on high-intensity laser-produced hot dense helium plasmas

    International Nuclear Information System (INIS)

    Sperling, P; Liseykina, T; Bauer, D; Redmer, R

    2013-01-01

    The introduction of brilliant free-electron lasers enables new pump–probe experiments to characterize warm and hot dense matter states, i.e. systems at solid-like densities and temperatures of one to several hundred eV. Such extreme conditions are relevant for high-energy density studies such as, e.g., in planetary physics and inertial confinement fusion. We consider here a liquid helium jet pumped with a high-intensity optical short-pulse laser that is subsequently probed with brilliant soft x-ray radiation. The optical short-pulse laser generates a strongly inhomogeneous helium plasma which is characterized with particle-in-cell simulations. We derive the respective Thomson scattering spectrum based on the Born–Mermin approximation for the dynamic structure factor considering the full density and temperature-dependent Thomson scattering cross section throughout the target. We observe plasmon modes that are generated in the interior of the target and study their temporal evolution. Such pump–probe experiments are promising tools to measure the important plasma parameters density and temperature. The method described here can be applied to various pump–probe scenarios by combining optical lasers, soft x-rays and hard x-ray sources. (paper)

  15. Soft x-ray emission from postpulse expanding laser-produced plasmas

    International Nuclear Information System (INIS)

    Weaver, J.L.; Feldman, U.; Mostovych, A.N.; Seely, J.F.; Colombant, D.; Holland, G.

    2003-01-01

    A diagnostic spectrometer has been developed at the Naval Research Laboratory to measure the time resolved absolute intensity of radiation emitted from targets irradiated by the Nike laser. The spectrometer consists of a dispersive transmission grating of 2500 lines/mm or 5000 lines/mm and a detection system consisting of an absolutely calibrated Si photodiode array and a charge coupled device camera. In this article, this spectrometer was used to study the spatial distribution of soft x-ray radiation from low Z elements (primarily carbon) that lasted tens of nanoseconds after the main laser illumination was over. We recorded soft x-ray emission as a function of the target material and target orientation with respect to the incoming laser beam and the spectrometer line of sight. While a number of spectral features have been identified in the data, the instrument's combined temporal and spatial resolution allowed observation of the plasma expansion from CH targets for up to ∼25 ns after the cessation of the main laser pulse. The inferred plasma expansion velocities are slightly higher than those previously reported

  16. Porous Nb-Ti based alloy produced from plasma spheroidized powder

    Directory of Open Access Journals (Sweden)

    Qijun Li

    Full Text Available Spherical Nb-Ti based alloy powder was prepared by the combination of plasma spheroidization and mechanical alloying. Phase constituents, microstructure and surface state of the powder, and pore characteristics of the resulting porous alloy were investigated. The results show that the undissolved W and V in the mechanically alloyed powder is fully alloyed after spheroidization, and single β phase is achieved. Particle size of the spheroidized powder is in the range of 20–110 μm. With the decrease of particle size, a transformation from typical dendrite solidification structure to fine cell microstructure occurs. The surface of the spheroidized powder is coated by a layer of oxides consisting mainly of TiO2 and Nb2O5. Probabilities of sinter-neck formation and particle coalescence increases with increasing sintering temperature. Porous skeleton with relatively homogeneous pore distribution and open pore channel is formed after vacuum sintering at 1700 °C, and the porosity is 32%. The sintering kinetic analysis indicates that grain boundary diffusion is the primary mass transport mechanism during sintering process. Keywords: Powder metallurgy, Nb-Ti based alloy, Porous material, Mechanical alloying, Plasma spheroidizing, Solidification microstructure

  17. Analysis of two colliding laser-produced plasmas by emission spectroscopy and fast photography

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Ake, C., E-mail: citlali.sanchez@ccadet.unam.m [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, Mexico D.F., C.P. 04510 (Mexico); Mustri-Trejo, D. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, Mexico D.F., C.P. 04510 (Mexico); Garcia-Fernandez, T. [Universidad Autonoma de la Ciudad de Mexico, Prolongacion San Isidro 151, Col. San Lorenzo Tezonco, Mexico DF, C.P. 09790 (Mexico); Villagran-Muniz, M. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, Mexico D.F., C.P. 04510 (Mexico)

    2010-05-15

    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, 495.37 and 630.10 nm) and Cu III (374.47 and 379.08 nm) due to the ionization that occurs during collisions of Cu and C species. It was found that the optimum delay between pulses, which yields the maximum emission enhancement of Cu ions, depends on the sampling distance. On the other hand, the emission intensity of C lines, C II (426.70 nm), C III (406.99 and 464.74 nm) and C IV (465.83 nm), decreased and the formation of C{sub 2} molecules was observed. A comparison between the temporal evolution of the individual plasmas and their collision performed by combining imaging and the time resolved emission diagnostics, revealed an increase of the electron temperature and electron density and the splitting of the plume into slow and fast components.

  18. Soft x-ray emission from postpulse expanding laser-produced plasmas

    Science.gov (United States)

    Weaver, J. L.; Feldman, U.; Mostovych, A. N.; Seely, J. F.; Colombant, D.; Holland, G.

    2003-12-01

    A diagnostic spectrometer has been developed at the Naval Research Laboratory to measure the time resolved absolute intensity of radiation emitted from targets irradiated by the Nike laser. The spectrometer consists of a dispersive transmission grating of 2500 lines/mm or 5000 lines/mm and a detection system consisting of an absolutely calibrated Si photodiode array and a charge coupled device camera. In this article, this spectrometer was used to study the spatial distribution of soft x-ray radiation from low Z elements (primarily carbon) that lasted tens of nanoseconds after the main laser illumination was over. We recorded soft x-ray emission as a function of the target material and target orientation with respect to the incoming laser beam and the spectrometer line of sight. While a number of spectral features have been identified in the data, the instrument's combined temporal and spatial resolution allowed observation of the plasma expansion from CH targets for up to ˜25 ns after the cessation of the main laser pulse. The inferred plasma expansion velocities are slightly higher than those previously reported.

  19. Polyurethane coating with thin polymer films produced by plasma polymerization of diglyme

    Science.gov (United States)

    Ribeiro, M. A.; Ramos, A. S.; Manfredini, M. I.; Alves, H. A.; Y Honda, R.; Kostov, K. G.; Lucena, E. F.; Ramos, E. C. T.; Mota, R. P.; Algatti, M. A.; Kayama, M. E.

    2009-05-01

    Aqueous-based polyurethane dispersions have been widely utilized as lubricants in textile, shoes, automotive, biomaterial and many other industries because they are less aggressive to surrounding environment. In this work thin films with different thickness were deposited on biocompatible polyurethane by plasma polymerization process using diethylene glycol dimethyl ether (Diglyme) as monomer. Molecular structure of the films was analyzed by Fourier Transform Infrared spectroscopy. The spectra exhibited absorption bands of O-H (3500-3200cm-1), C-H (3000-2900cm-1), C=O (1730-1650cm-1), C-O and C-O-C bonds at 1200-1600cm-1. The samples wettability was evaluated by measurements of contact angle using different liquids such as water, glycerol, poly-ethane and CMC. The polyurethane surface showed hydrophilic behavior after diglyme plasma-deposition with contact angle dropping from 85° to 22°. Scanning Electron Microscopy revealed that diglyme films covered uniformly the polyurethane surfaces ensuring to it a biocompatible characteristic.

  20. Analysis of neon soft x-ray spectra from short-pulse laser-produced plasmas

    International Nuclear Information System (INIS)

    Abare, A.C.; Keane, C.J.; Crane, J.K.; DaSilva, L.B.; Lee, R.W.; Perry, M.D.; Falcone, R.W.

    1993-04-01

    We report preliminary results from the analysis of streaked soft x-ray neon spectra a gas jet target. In obtained from the interaction of a picosecond Nd:glass laser with these experiments streaked spectra show prompt harmonic emission followed by longer time duration soft x-ray line emission. The majority of the line emission observed was found to originate from Li- and Be-like Ne and the major transitions in the observed spectra have been identified. Li-like emission lines were observed to decay faster in time than Be-like transitions, suggesting that recombination is taking place. Line ratios of n=4-2 and n=3-2 transitions supported the view that these lines were optically thin and thick, respectively. The time history of Li-like Ne 2p-4d and 2p-3d lines is in good agreement with a simple adiabatic expansion model coupled to a time dependent collisional-radiative code. Further x-ray spectroscopic analysis is underway which is aimed at diagnosing plasma conditions and assessing the potential of this recombining neon plasma as a quasi-steady-state recombination x-ray laser medium

  1. Polyurethane coating with thin polymer films produced by plasma polymerization of diglyme

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, M A; Ramos, A S; Manfredini, M I; Alves, H A; Ramos, E C T [UNIVAP, Sao Jose dos Campos, SP (Brazil); Honda, R Y; Kostov, K G; Lucena, E F; Mota, R P; Algatti, M A; Kayama, M E, E-mail: rmota@feg.unesp.b [FEG-DFQ-UNESP, Av. Ariberto Pereira da Cunha 333, 12516-410 - Guaratingueta, SP (Brazil)

    2009-05-01

    Aqueous-based polyurethane dispersions have been widely utilized as lubricants in textile, shoes, automotive, biomaterial and many other industries because they are less aggressive to surrounding environment. In this work thin films with different thickness were deposited on biocompatible polyurethane by plasma polymerization process using diethylene glycol dimethyl ether (Diglyme) as monomer. Molecular structure of the films was analyzed by Fourier Transform Infrared spectroscopy. The spectra exhibited absorption bands of O-H (3500-3200cm{sup -1}), C-H (3000-2900cm{sup -1}), C=O (1730-1650cm{sup -1}), C-O and C-O-C bonds at 1200-1600cm{sup -1}. The samples wettability was evaluated by measurements of contact angle using different liquids such as water, glycerol, poly-ethane and CMC. The polyurethane surface showed hydrophilic behavior after diglyme plasma-deposition with contact angle dropping from 85 deg. to 22 deg. Scanning Electron Microscopy revealed that diglyme films covered uniformly the polyurethane surfaces ensuring to it a biocompatible characteristic.

  2. A Simple Method to Functionalize the Surface of Plasma Electrolytic Oxidation Produced TiO2 Coatings for Growing Hydroxyapatite

    International Nuclear Information System (INIS)

    Teng, Huan-Ping; Yang, Chia-Jung; Lin, Jia-Fu; Huang, Yu-Hsin; Lu, Fu-Hsing

    2016-01-01

    Highlights: • TiO 2 coatings with porous surfaces were produced by plasma electrolytic oxidation. • Simple pre-immersion in K 2 HPO 4 could functionalize the surfaces of the TiO 2 . • Such pre-immersion enhanced substantially the growth of hydroxyapatite in SBF. • Growth mechanisms of hydroxyapatite via the pre-immersion have been proposed. • MTT assay shows great osteoblast-like cell activity on the obtained hydroxyapatite. - Abstract: Conventionally, hydrothermal treatment was often used to modify the TiO 2 surface prior to the growth of hydroxyapatite (HA) that is one of the most important implant biomaterials. In this work, a simple pre-immersion of the obtained TiO 2 in a weak base, instead of the conventionally high pressure-temperature hydrothermal pre-treatment, was conducted prior to the growth of HA. Firstly, anatase TiO 2 coatings with porous surfaces were produced by plasma electrolytic oxidation with optimized processing parameters. X-ray diffraction patterns and field-emission microscopy reveal that the anatase TiO 2 films with porous surfaces were produced by plasma electrolytic oxidation. Subsequently, the films were pre-immersed in 0.1–2 M K 2 HPO 4 solutions for only 10 min. Fourier transform infrared spectroscopy shows that the −OH functional groups were generated after such pre-immersion, which could enhance significantly the growth of a single phase of HA in simulated body fluid (SBF). Growth mechanisms of HA via the pre-immersion treatment and soaking in SBF have been proposed. Moreover, the proliferation rate and attachment of the MG-63 osteoblast cells were greatly enhanced on the obtained HA compared to that without the immersion pre-treatment from the MTT assay and morphology analyses. This simple immersion pre-treatment evidently provides an easy route for the growth of HA and has great potential for biomedical applications.

  3. Plasma parameters in the vicinity of the quartz window of a low pressure surface wave discharge produced in O2

    DEFF Research Database (Denmark)

    Nakao, S.; Stamate, Eugen; Sugai, H.

    2007-01-01

    Plasma parameters in the vicinity of the dielectric window of a low density, microwave discharge produced in 0, at 915 N/FHz are investigated by a spherical probe and optical emission spectroscopy while the microwave field distribution is measured by a spectrum analyzer. The electron energy...... distribution function is found to be strongly dependent on the position with respect to the slot antenna, exhibiting a group of energetic electrons at locations where the electric field and the optical intensity exhibit maximum values. The density of energetic electrons decreases sharply just a few cm away...

  4. Application of hydrogen-plasma technology for property modification of silicon and producing the silicon-based structures

    International Nuclear Information System (INIS)

    Fedotov, A.K.; Mazanik, A.V.; Ul'yashin, A.G.; Dzhob, R; Farner, V.R.

    2000-01-01

    Effects of atomic hydrogen on the properties of Czochralski-grown single crystal silicon as well as polycrystalline shaped silicon have been investigated. It was established that the buried defect layers created by high-energy hydrogen or helium ion implantation act as a good getter centers for hydrogen atoms introduced in silicon in the process of hydrogen plasma hydrogenation. Atomic hydrogen was shown to be active as a catalyzer significantly enhancing the rate of thermal donors formation in p-type single crystal silicon. This effect can be used for n-p- and p-n-p-silicon based device structures producing [ru

  5. Simultaneously time- and space-resolved spectroscopic characterization of laser-produced plasmas

    International Nuclear Information System (INIS)

    Charatis, G.; Young, B.K.F.; Busch, G.E.

    1988-01-01

    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

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

    Science.gov (United States)

    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.

  7. Parametric emittance measurements of electron beams produced by a laser plasma accelerator

    Science.gov (United States)

    Barber, S. K.; van Tilborg, J.; Schroeder, C. B.; Lehe, R.; Tsai, H.-E.; Swanson, K. K.; Steinke, S.; Nakamura, K.; Geddes, C. G. R.; Benedetti, C.; Esarey, E.; Leemans, W. P.

    2018-05-01

    Laser plasma accelerators (LPA) offer an exciting possibility to deliver high energy, high brightness electrons beams in drastically smaller distance scales than is typical for conventional accelerators. As such, LPAs draw considerable attention as potential drivers for next generation light sources and for a compact linear collider. In order to asses the viability of an LPA source for a particular application, the brightness of the source should be properly characterized. In this paper, we present charge dependent transverse emittance measurements of LPA sources using both ionization injection and shock induced density down ramp injection, with the latter delivering smaller transverse emittances by a factor of two when controlling for charge density. The single shot emittance method is described in detail with a discussion on limitations related to second order transport effects. The direct role of space charge is explored through a series of simulations and found to be consistent with experimental observations.

  8. Crystalline and amorphous phases in carbon nitride films produced by intense high-pressure plasma

    International Nuclear Information System (INIS)

    Gurarie, V.N.; Orlov, A.V.; Bursill, L.A.; JuLin, P.; Nugent, K.W.; Chon, J.W.; Prawer, S.

    1997-01-01

    Carbon-nitride films are prepared using a high-intensity pulsed plasma deposition technique. A wide range of nitrogen pressure and discharge intensity are used to investigate their effect on the morphology, nitrogen content, structure, bonding, phase composition and mechanical characteristics of the CN films deposited. Increasing the nitrogen pressure from 0.1 atm to 10 atm results in an increase of nitrogen incorporation into CN films to maximum of 45 at %. Under the high-energy density deposition conditions which involve ablation of the quartz substrate the CN films are found to incorporate in excess of 60 at %N. Raman spectra of these films contain sharp peaks characteristic of a distinct crystalline CN phase. TEM diffraction patterns for the films deposited below 1 atm unambiguously show the presence of micron-sized crystals displaying a cubic symmetry. (authors)

  9. Extraction of volume produced H- or D- ions from a sheet plasma, 2

    International Nuclear Information System (INIS)

    Uramoto, Joshin.

    1984-02-01

    A development to large area H - or D - ion source is tried by using three extraction electrodes: The first electrode bias voltage is set near the wall potential (floating), the second electrode is set near 13 % of main extraction voltage and the third electrode is the main acceleration electrode. An ion current of 13 mA (3.3 mA/cm 2 ) for H - or 11 mA (2.8 mA/ cm 2 ) for D - at 3 KeV is extracted from 9 apertures of 6 mm phi in 4 cm 2 outside of the sheet plasma (14 cm wide and 1.0 cm thick) under a pressure of 7.7 x 10 -4 H2 or D2 gas and a weak magnetic field 50 gauss. Then, it is noted that the corresponding electron current is suppressed below 1/10 of the H - or D - ion current. (author)

  10. Decreased Bacterial Attachment and Protein Adsorption to Coatings Produced by Low Enegy Plasma Polymerization

    DEFF Research Database (Denmark)

    Andersen, T.E.; Kingshott, Peter; Benter, M.

    .figure) .and E. coli grown on uncoated silicone compared to PP-PVP coated silicone (right figure). Results from the flow chamber analysis shows PP-PVP to be very good at preventing E. coli colonization during prolonged growth in flow chamber. At this point other surfaces and bacteria remains to be tested...... adsorption and bacteria attachment/colonization. This is emphasized by the fact that long dwelling urinary catheters, which is a typical silicone medical device, causes 5% per day incidence of urinary tract infection [1,2]. A demand therefore exists for surface modifications providing the silicone material......-coated crystals were then treated with one of the plasma polymerized coatings. Adsorption of fibrinogen, human serum albumin or immunoglobulin G was measured using a QCM-D instrument [5] (model E4, Q-Sense AB, Vastra Frolunda, Sweden) using a solution of 50llg/1 protein in PBS buffer. Results and Discussion: Our...

  11. X-ray spectroscopy of a thin foil plasma produced by a short-pulse high-intensity laser

    International Nuclear Information System (INIS)

    Audebert, P.; Nagels, V.; Geindre, J.P.; Dorchies, F.; Peyrusse, O.; Gary, S.; Girard, F.; Shepherd, R.; Gauthier, J.C.; Chenais-Popovics, C.

    2003-01-01

    High density and temperature plasmas have been generated by irradiating thin foils of various elements with a high-energy subpicosecond laser pulse. The X-ray emission duration was studied by time-resolved X-ray spectroscopy. Frequency domain interferometry provided a measurement of the hydrodynamic expansion of the back of the foil as a function of time. The effect of longitudinal temperature gradients, i.e., gradients perpendicular to the surface, were decreased using very thin foil targets. Additionally, radial gradients effects, i.e., gradients parallel to the surface, were limited by using a 50 μm pinhole on target. The Al, Se and Sm spectra, recorded in the range 7.7-8 Angst. using a conical crystal spectrometer coupled to an 800 fs resolution streak camera, lasted a few picoseconds. Sm spectra showed no spectral features in this wavelength range, providing a spectrally homogeneous backlighter for future experiments. The main features of the experimental time-resolved spectra have been well reproduced with one-dimensional hydrodynamic simulations of the free expansion of a plasma heated at a given initial temperature obtained from the expansion velocity of the rear critical surface of the plasma

  12. Non-inductive plasma initiation and plasma current ramp-up on the TST-2 spherical tokamak

    International Nuclear Information System (INIS)

    Takase, Y.; Ejiri, A.; Oosako, T.; Shinya, T.; Ambo, T.; Furui, H.; Kato, K.; Nakanishi, A.; Sakamoto, T.; Kakuda, H.; Wakatsuki, T.; Hashimoto, T.; Hiratsuka, J.; Kasahara, H.; Kumazawa, R.; Mutoh, T.; Saito, K.; Seki, T.; Moeller, C.P.; Nagashima, Y.

    2013-01-01

    Plasma current (I p ) start-up in a spherical tokamak (ST) by waves in the lower-hybrid (LH) frequency range was investigated on TST-2. A low current (∼1 kA) ST configuration can be formed by waves over a broad frequency range (21 MHz–8.2 GHz in TST-2), but further I p ramp-up (to ∼10 kA) is most efficient with waves in the LH frequency range. I p ramp-up to 15 kA was achieved with 60 kW of net RF power P RF in the fast wave (FW) polarization at 200 MHz excited by the inductively coupled combline antenna. X-ray measurements showed that the photon flux and temperature are higher in the direction opposite to I p , consistent with acceleration of electrons by a uni-directional RF wave. There is evidence that the LH wave is excited nonlinearly by the FW, based on the frequency spectra measured by magnetic probes. Similar efficiencies of I p ramp-up were obtained with the inductive combline antenna and the dielectric-loaded waveguide array (‘grill’) antenna, and tendencies for the current drive efficiency to increase with plasma current and toroidal field were observed. During operation of the grill antenna, wavevector components were measured by an array of magnetic probes. Results were qualitatively consistent with expectations based on dispersion relations for the FW and the LH wave. A capacitively coupled combline antenna has been developed to improve coupling to the plasma and the wavenumber spectrum of the excited LH wave, and will be tested in 2013. (paper)

  13. An Investigation of Porous Structure of TiNi-Based SHS-Materials Produced at Different Initial Synthesis Temperatures

    Science.gov (United States)

    Khodorenko, V. N.; Anikeev, S. G.; Kokorev, O. V.; Yasenchuk, Yu. F.; Gunther, V. É.

    2018-02-01

    An investigation of structural characteristics and behavior of TiNi-based pore-permeable materials manufactured by the methods of selfpropagating high-temperature synthesis (SHS) at the initial synthesis temperatures T = 400 and 600°C is performed. It is shown that depending on the temperature regime, the resulting structure and properties of the material can differ. It is found out that the SHS-material produced at the initial synthesis temperature T = 400°C possesses the largest number of micropores in the pore wall surface structure due to a high phase inhomogeneity of the alloy. The regime of structure optimization of the resulting materials is described and the main stages of formation of the pore wall microporous surfaces are revealed. It is demonstrated that after optimization of the surface structure of a TiNi-based fine-pore alloy by its chemical etching, the fraction of micropores measuring in size less than 50 nm increased from 59 to 68%, while the number of pores larger than 1 μm increased twofold from 11 to 22%. In addition, peculiar features of interaction between certain cell cultures with the surface of the SHS-material manufactured at different initial synthesis temperatures are revealed. It is found out that the dynamics of the cell material integration depends on the pore wall surface morphology and dimensions of macropores.

  14. Structure and properties of nitrided surface layer produced on NiTi shape memory alloy by low temperature plasma nitriding

    International Nuclear Information System (INIS)

    Czarnowska, Elżbieta; Borowski, Tomasz; Sowińska, Agnieszka; Lelątko, Józef; Oleksiak, Justyna; Kamiński, Janusz; Tarnowski, Michał; Wierzchoń, Tadeusz

    2015-01-01

    Highlights: • Low temperature plasma nitriding process of NiTi shape memory alloy is presented. • The possibility of treatment details of sophisticated shape. • TiN surface layer has diffusive character. • TiN surface layer increases corrosion resistance of NiTi alloy. • Produced TiN layer modify the biological properties of NiTi alloy. - Abstract: NiTi shape memory alloys are used for bone and cardiological implants. However, on account of the metallosis effect, i.e. the release of the alloy elements into surrounding tissues, they are subjected to various surface treatment processes in order to improve their corrosion resistance and biocompatibility without influencing the required shape memory properties. In this paper, the microstructure, topography and morphology of TiN surface layer on NiTi alloy, and corrosion resistance, both before and after nitriding in low-temperature plasma at 290 °C, are presented. Examinations with the use of the potentiodynamic and electrochemical impedance spectroscopy methods were carried out and show an increase of corrosion resistance in Ringer's solution after glow-discharge nitriding. This surface titanium nitride layer also improved the adhesion of platelets and the proliferation of osteoblasts, which was investigated in in vitro experiments with human cells. Experimental data revealed that nitriding NiTi shape memory alloy under low-temperature plasma improves its properties for bone implant applications

  15. Role of ion magnetization in formation of radial density profile in magnetically expanding plasma produced by helicon antenna

    Science.gov (United States)

    Yadav, Sonu; Ghosh, Soumen; Bose, Sayak; Barada, Kshitish K.; Pal, Rabindranath; Chattopadhyay, Prabal K.

    2018-04-01

    Experimentally, the density profile in the magnetic nozzle of a helicon antenna based plasma device is seen to be modified from being centrally peaked to that of hollow nature as the external magnetic field is increased. It occurs above a characteristic field value when the ions become magnetized in the expansion chamber. The density profile in the source chamber behind the nozzle, however, remains peaked on-axis irrespective of the magnetic field. The electron temperature there is observed to be hollow and this nature is carried to the expansion chamber along the field line. In the electron energy distribution near the off axis peak location, a high energy tail exists. Rotation of these tail electrons in the azimuthal direction due to the gradient-B drift in the expansion chamber leads to an additional off-axis ionization and forms the hollow density profile. It seems that if the ions are not magnetized, then the off-axially produced additional plasma is not confined and the density profile retains the on-axis peak nature. The present experiment successfully demonstrates how the knowledge of the ion magnetization together with tail electrons significantly contributes to the design of an efficient helicon plasma based thruster.

  16. Electromagnetic radiation emitted by a plasma produced in air by laser pulses with lambda = 10.6 μm

    International Nuclear Information System (INIS)

    Danilychev, V.A.; Zvorykin, V.D.; Kholin, I.V.; Chugunov, A.Y.

    1981-01-01

    The spectrum, brightness, and energy have been measured for the electromagnetic radiation emitted by a plasma produced in air near a solid surface by pulses from a high-power CO 2 laser. The air pressure was varied over the range p 0 = 0.1--760 torr, and the laser power density was varied over the range q = 5 x 10 6 --10 8 W/cm 2 . At p 0 > or approx. =2--5 torr the radiation properties of the plasma are determined by a laser-beam absorption wave which arises in the gas. The maximum brightness temperature, T/sub b/approx. =50 000 K (lambda = 400 +- 20 nm), is reached at p 0 = 25 torr. The emission spectrum is quite different from an equilibrium spectrum, consisting primarily of NII, OII, and NIII lines. The total energy radiation by the plasma in the wavelength interval 360--2600 nm into a solid angle of 4π sr reaches 2.3% of the laser pulse energy

  17. Structure and properties of nitrided surface layer produced on NiTi shape memory alloy by low temperature plasma nitriding

    Energy Technology Data Exchange (ETDEWEB)

    Czarnowska, Elżbieta [Children' s Memorial Health Institute, Pathology Department, Al. Dzieci Polskich 20, 04-730 Warsaw (Poland); Borowski, Tomasz [Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw (Poland); Sowińska, Agnieszka [Children' s Memorial Health Institute, Pathology Department, Al. Dzieci Polskich 20, 04-730 Warsaw (Poland); Lelątko, Józef [Silesia University, Faculty of Computer Science and Materials Science, 75 Pułku Piechoty 1A, 41-500 Chorzów (Poland); Oleksiak, Justyna; Kamiński, Janusz; Tarnowski, Michał [Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw (Poland); Wierzchoń, Tadeusz, E-mail: twierz@inmat.pw.edu.pl [Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw (Poland)

    2015-04-15

    Highlights: • Low temperature plasma nitriding process of NiTi shape memory alloy is presented. • The possibility of treatment details of sophisticated shape. • TiN surface layer has diffusive character. • TiN surface layer increases corrosion resistance of NiTi alloy. • Produced TiN layer modify the biological properties of NiTi alloy. - Abstract: NiTi shape memory alloys are used for bone and cardiological implants. However, on account of the metallosis effect, i.e. the release of the alloy elements into surrounding tissues, they are subjected to various surface treatment processes in order to improve their corrosion resistance and biocompatibility without influencing the required shape memory properties. In this paper, the microstructure, topography and morphology of TiN surface layer on NiTi alloy, and corrosion resistance, both before and after nitriding in low-temperature plasma at 290 °C, are presented. Examinations with the use of the potentiodynamic and electrochemical impedance spectroscopy methods were carried out and show an increase of corrosion resistance in Ringer's solution after glow-discharge nitriding. This surface titanium nitride layer also improved the adhesion of platelets and the proliferation of osteoblasts, which was investigated in in vitro experiments with human cells. Experimental data revealed that nitriding NiTi shape memory alloy under low-temperature plasma improves its properties for bone implant applications.

  18. Processes for forming exoergic structures with the use of a plasma and for producing dense refractory bodies of arbitrary shape therefrom

    International Nuclear Information System (INIS)

    Holt, J.B.; Kelly, M.D.

    1990-01-01

    Plasma spraying methods of forming exoergic structures and coatings, as well as exoergic structures produced by such methods, are presented. 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 the plasma sprayed materials, either under an inert gas pressure or not, to form refractory materials of varying densities and of varying shapes

  19. Microstructural, mechanical and oxidation features of NiCoCrAlY coating produced by plasma activated EB-PVD

    International Nuclear Information System (INIS)

    He, Jian; Guo, Hongbo; Peng, Hui; Gong, Shengkai

    2013-01-01

    NiCoCrAlY coatings produced by electron beam-physical vapor deposition (EB-PVD) have been extensively used as the oxidation resistance coatings or suitable bond coats in thermal barrier coating (TBC) system. However, the inherent imperfections caused by EB-PVD process degrade the oxidation resistance of the coatings. In the present work, NiCoCrAlY coatings were creatively produced by plasma activated electron beam-physical vapor deposition (PA EB-PVD). The novel coatings showed a terraced substructure on the surface of each grain due to the increased energy of metal ions and enhanced mobility of adatoms. Also a strong (1 1 1) crystallographic texture of γ/γ′ grains was observed. The toughness of the coatings got remarkably improved compared with the coatings deposited by conventional EB-PVD and the oxidation behavior at 1373 K showed that the novel coatings had excellent oxidation resistance. The possible mechanism was finally discussed.

  20. A scheme to produce a dense positronium plasma for an antihydrogen experiment

    Energy Technology Data Exchange (ETDEWEB)

    Perez, P. [CEA Saclay, DSM/IRFU, 91191 Gif-sur-Yvette Cedex (France)], E-mail: patrice.perez@cea.fr; Liszkay, L.; Rey, J.-M.; Delferrierre, O.; Blideanu, V.; Carty, M.; Curtoni, A.; Ruiz, N.; Sauce, Y. [CEA Saclay, DSM/IRFU, 91191 Gif-sur-Yvette Cedex (France)

    2008-10-31

    A 6 MeV industrial electron linac with 0.2 mA average current will be installed in December 2007 in CEA-Saclay. Equipped with a tungsten target and moderator, it is aimed at producing rates of order 10{sup 8} s{sup -1} slow positrons. This setup is part of a project to demonstrate the feasibility of an experiment to produce the H-bar{sup +} ion for a free fall measurement of H-bar. The energy is below the neutron activation threshold. Its small size and cost could be of interest for a university laboratory or industry, and could be envisaged as a replacement source for the antihydrogen experiments at CERN.

  1. Low-debris, efficient laser-produced plasma extreme ultraviolet source by use of a regenerative liquid microjet target containing tin dioxide (SnO2) nanoparticles

    Science.gov (United States)

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

    2006-05-01

    We demonstrated a low-debris, efficient laser-produced plasma extreme ultraviolet (EUV) source by use of a regenerative liquid microjet target containing tin-dioxide (SnO2) nanoparticles. By using a low SnO2 concentration (6%) solution and dual laser pulses for the plasma control, we observed the EUV conversion efficiency of 1.2% with undetectable debris.

  2. Low-debris, efficient laser-produced plasma extreme ultraviolet source by use of a regenerative liquid microjet target containing tin dioxide (SnO2) nanoparticles

    International Nuclear Information System (INIS)

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

    2006-01-01

    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 2 ) nanoparticles. By using a low SnO 2 concentration (6%) solution and dual laser pulses for the plasma control, we observed the EUV conversion efficiency of 1.2% with undetectable debris

  3. First in situ plasma and neutral gas measurements at comet Halley: initial VEGA results

    International Nuclear Information System (INIS)

    Gringauz, K.I.; Remizov, A.P.; Gombosi, T.I.

    1986-04-01

    The first in situ observations and a description of the large scale behaviour of comet Halley's plasma environment are presented. The scientific objectives of the PLASMAG-1 experiment were as follows: to study the change of plasma parameters and distributions as a function of cometocentric distance; to investigate the existence and structure of the cometary bow shock; to determine the change in chemical composition of the heavily mass loaded plasma as the spacecraft approached the comet; and to measure the neutral gas distribution along the spacecraft trajectory. (author)

  4. Erosion resistance and adhesion of composite metal/ceramic coatings produced by plasma spraying

    OpenAIRE

    Ramm , D.; Hutchings , I.; Clyne , T.

    1993-01-01

    Ceramic coatings can exhibit greater erosion resistance than most metallic coatings. Such coatings are conveniently produced by thermal spraying. Unfortunately, thermally sprayed ceramic coatings often exhibit poor adhesion, partly as a consequence of the development of residual stresses during spraying and subsequent cooling. Composite coatings have been studied using aluminium/alumina deposits on steel substrates. The incorporation of ceramics within a ductile matrix has potential for sharp...

  5. Plasma synthesis and HPHT consolidation of BN nanoparticles, nanospheres, and nanotubes to produce nanocrystalline cubic boron nitride

    Science.gov (United States)

    Stout, Christopher

    Plasma methods offer a variety of advantages to nanomaterials synthesis. The process is robust, allowing varying particle sizes and phases to be generated simply by modifying key parameters. The work here demonstrates a novel approach to nanopowder synthesis using inductively-coupled plasma to decompose precursor, which are then quenched to produce a variety of boron nitride (BN)-phase nanoparticles, including cubic phase, along with short-range-order nanospheres (e.g., nano-onions) and BN nanotubes. Cubic BN (c-BN) powders can be generated through direct deposition onto a chilled substrate. The extremely-high pyrolysis temperatures afforded by the equilibrium plasma offer a unique particle growth environment, accommodating long deposition times while exposing resulting powders to temperatures in excess of 5000K without any additional particle nucleation and growth. Such conditions can yield short-range ordered amorphous BN structures in the form of 20nm diameter nanospheres. Finally, when introducing a rapid-quenching counter-flow gas against the plasma jet, high aspect ratio nanotubes are synthesized, which are collected on substrate situated radially. The benefits of these morphologies are also evident in high-pressure/high-temperature consolidation experiments, where nanoparticle phases can offer a favorable conversion route to super-hard c-BN while maintaining nanocrystallinity. Experiments using these morphologies are shown to begin to yield c-BN conversion at conditions as low as 2.0 GPa and 1500°C when using micron sized c-BN seeding to create localized regions of high pressures due to Hertzian forces acting on the nanoparticles.

  6. Alteration in plasma corticosterone levels following long term oral administration of lead produces depression like symptoms in rats.

    Science.gov (United States)

    Haider, Saida; Saleem, Sadia; Tabassum, Saiqa; Khaliq, Saima; Shamim, Saima; Batool, Zehra; Parveen, Tahira; Inam, Qurat-ul-ain; Haleem, Darakhshan J

    2013-03-01

    Lead toxicity is known to induce a broad range of physiological, biochemical and behavioral dysfunctions that may result in adverse effects on several organs, including the central nervous system. Long-term exposure to low levels of lead (Pb(2+)) has been shown to produce behavioral deficits in rodents and humans by affecting hypothalamic-pituitary-adrenal (HPA) axis. These deficits are thought to be associated with altered brain monoamine neurotransmission and due to changes in glucocorticoids levels. This study was designed to investigate the effects of Pb(2+)exposure on growth rate, locomotor activity, anxiety, depression, plasma corticosterone and brain serotonin (5-HT) levels in rats. Rats were exposed to lead in drinking water (500 ppm; lead acetate) for 5 weeks. The assessment of depression was done using the forced swimming test (FST). Estimation of brain 5-HT was determined by high-performance liquid chromatography with electrochemical detection. Plasma corticosterone was determined by spectrofluorimetric method. The present study showed that long term exposure to Pb(2+) significantly decreased the food intake followed by the decrease in growth rate in Pb(2+)exposed rats as compared to control group. No significant changes in open field activity were observed following Pb(2+)exposure while significant increase in anxiogenic effect was observed. Increased plasma corticosterone and decreased 5-HT levels were exhibited by Pb(2+)exposed rats as compared to controls. A significant increase in depressive like symptoms was exhibited by Pb(2+)exposed rats as compared to control rats. The results are discussed in the context of Pb(2+) inducing a stress-like response in rats leading to changes in plasma corticosterone and brain 5-HT levels via altering tryptophan pyrrolase activity.

  7. Hydrogen generation from water using Mg nanopowder produced by arc plasma method

    Directory of Open Access Journals (Sweden)

    Masahiro Uda, Hideo Okuyama, Tohru S Suzuki and Yoshio Sakka

    2012-01-01

    Full Text Available We report that hydrogen gas can be easily produced from water at room temperature using a Mg nanopowder (30–1000 nm particles, average diameter 265 nm. The Mg nanopowder was produced by dc arc melting of a Mg ingot in a chamber with mixed-gas atmosphere (20% N2–80% Ar at 0.1 MPa using custom-built nanopowder production equipment. The Mg nanopowder was passivated with a gas mixture of 1% O2 in Ar for 12 h in the final step of the synthesis, after which the nanopowder could be safely handled in ambient air. The nanopowder vigorously reacted with water at room temperature, producing 110 ml of hydrogen gas per 1 g of powder in 600 s. This amount corresponds to 11% of the hydrogen that could be generated by the stoichiometric reaction between Mg and water. Mg(OH2 flakes formed on the surface of the Mg particles as a result of this reaction. They easily peeled off, and the generation of hydrogen continued until all the Mg was consumed.

  8. Microstructure and mechanical behavior of ODS and non-ODS Fe–14Cr model alloys produced by spark plasma sintering

    International Nuclear Information System (INIS)

    Auger, M.A.; Castro, V. de; Leguey, T.; Muñoz, A.; Pareja, R.

    2013-01-01

    In this work the spark plasma sintering (SPS) technique has been explored as an alternative consolidation route for producing ultra-fine grained Fe–14Cr model alloys containing a dispersion of oxide nanoparticles. Elemental powders of Fe and Cr, and nanosized Y 2 O 3 powder have been mechanically alloyed in a planetary ball mill and rapidly sintered in a spark plasma furnace. Two alloys, with nominal compositions Fe–14%Cr and Fe–14%Cr–0.3%Y 2 O 3 (wt.%), have been fabricated and their microstructure and mechanical properties investigated. The results have been compared with those obtained for other powder metallurgy processed alloys of the same composition but consolidated by hot isostatic pressing. The SPS technique under the present conditions has produced Fe–14Cr materials that apparently exhibit different microstructures yielding inferior mechanical properties than the counterpart material consolidated by hot isostatic pressing. Although the presence of a dispersion of Y-rich particles is evident, the oxide dispersion strengthened (ODS) Fe–14Cr alloy consolidated by SPS exhibits poor tensile properties. The extensive decoration of the powder particle surfaces with Cr-rich precipitates and the residual porosity appear to be responsible for the impaired properties of this ODS alloy consolidated by SPS

  9. Microstructure and mechanical behavior of ODS and non-ODS Fe–14Cr model alloys produced by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Auger, M.A.; Castro, V. de [Departamento de Física, Universidad Carlos III de Madrid, 28911 Leganés (Spain); Leguey, T., E-mail: leguey@fis.uc3m.es [Departamento de Física, Universidad Carlos III de Madrid, 28911 Leganés (Spain); Muñoz, A.; Pareja, R. [Departamento de Física, Universidad Carlos III de Madrid, 28911 Leganés (Spain)

    2013-05-15

    In this work the spark plasma sintering (SPS) technique has been explored as an alternative consolidation route for producing ultra-fine grained Fe–14Cr model alloys containing a dispersion of oxide nanoparticles. Elemental powders of Fe and Cr, and nanosized Y{sub 2}O{sub 3} powder have been mechanically alloyed in a planetary ball mill and rapidly sintered in a spark plasma furnace. Two alloys, with nominal compositions Fe–14%Cr and Fe–14%Cr–0.3%Y{sub 2}O{sub 3} (wt.%), have been fabricated and their microstructure and mechanical properties investigated. The results have been compared with those obtained for other powder metallurgy processed alloys of the same composition but consolidated by hot isostatic pressing. The SPS technique under the present conditions has produced Fe–14Cr materials that apparently exhibit different microstructures yielding inferior mechanical properties than the counterpart material consolidated by hot isostatic pressing. Although the presence of a dispersion of Y-rich particles is evident, the oxide dispersion strengthened (ODS) Fe–14Cr alloy consolidated by SPS exhibits poor tensile properties. The extensive decoration of the powder particle surfaces with Cr-rich precipitates and the residual porosity appear to be responsible for the impaired properties of this ODS alloy consolidated by SPS.

  10. Evolution of an electron-positron plasma produced by induced gravitational collapse in binary-driven hypernovae

    Directory of Open Access Journals (Sweden)

    Melon Fuksman J. D.

    2018-01-01

    Full Text Available The binary-driven hypernova (BdHN model has been introduced in the past years, to explain a subfamily of gamma-ray bursts (GRBs with energies Eiso ≥ 1052 erg associated with type Ic supernovae. Such BdHNe have as progenitor a tight binary system composed of a carbon-oxigen (CO core and a neutron star undergoing an induced gravitational collapse to a black hole, triggered by the CO core explosion as a supernova (SN. This collapse produces an optically-thick e+e- plasma, which expands and impacts onto the SN ejecta. This process is here considered as a candidate for the production of X-ray flares, which are frequently observed following the prompt emission of GRBs. In this work we follow the evolution of the e+e- plasma as it interacts with the SN ejecta, by solving the equations of relativistic hydrodynamics numerically. Our results are compatible with the Lorentz factors estimated for the sources that produce the flares, of typically Γ ≲ 4.

  11. Development of an encapsulation method using plasma arc welding to produce iodine-125 seeds for brachytherapy

    International Nuclear Information System (INIS)

    Feher, Anselmo; Calvo, Wilson A.P.; Rostelato, Maria E.C.M.; Zeituni, Carlos A.; Somessari, Samir L.; Costa, Osvaldo L.; Moura, Joao A.; Moura, Eduardo S.; Souza, Carla D.; Rela, Paulo R.

    2011-01-01

    The prostate cancer, which is the second cause of death by cancer in men, overcome only by lung cancer is public health problem in Brazil. Brachytherapy is among the possible available treatments for prostate cancer, in which small seeds containing Iodine-125 radioisotope are implanted into the prostate gland. The seed consists of a titanium sealed capsule with 0.8 mm external diameter and 4.5 mm length, containing a central silver wire with adsorbed Iodine-125. The Plasma Arc Welding (PAW) is one of the viable techniques for sealing process. The equipment used in this technique is less costly than in other processes, such as, Laser Beam Welding (LBW). The main purpose of this work was the development of an encapsulation method using PAW. The development of this work has presented the following phases: cutting and cleaning titanium tube, determination of the welding parameters, development of a titanium tube holding device for PAW, sealed sources validation according to ISO 2919 - Sealed Radioactive Sources - General Requirements and Classification, and metallographic assays. The developed procedure to seal Iodine-125 seeds using PAW has shown high efficiency, satisfying all the established requirements of ISO 2919. The results obtained in this work will give the possibility to establish a routine production process according to the orientations presented in resolution RDC 17 - Good Manufacturing Practices to Medical Products defined by the ANVISA - National Agency of Sanitary Surveillance. (author)

  12. Dynamics of ZnO laser produced plasma in high pressure argon

    International Nuclear Information System (INIS)

    Kaydashev, V.E.; Lunney, J.G.

    2011-01-01

    Pulsed laser deposition of ZnO in high pressure gas offers a route for the catalyst-free preparation of ZnO nanorods less than 10 nm in diameter. This paper describes the results of some experiments to investigate the laser plume dynamics in the high gas pressure (5 x 10 3 -10 4 Pa) regime used for PLD of ZnO nanorods. In this regime the ablation plume is strongly coupled to the gas and the plume expansion is brought to a halt within about 1 cm from the target. A 248 nm excimer laser was used to ablate a ceramic ZnO target in various pressures of argon. Time- and space-resolved UV/vis emission spectroscopy and Langmuir probe measurements were used to diagnose the plasma and follow the plume dynamics. By measuring the spatial profiles of Zn I and Zn II spectral lines it was possible to follow the propagation of the external and internal shock waves associated with the interaction of the ablation plume with the gas. The Langmuir probe measurements showed that the electron density was 10 9 -10 10 cm -3 and the electron temperature was several eV. At these conditions the ionization equilibrium is described by the collisional-radiative model. The plume dynamics was also studied for ZnO targets doped with elements which are lighter (Mg), comparable to (Ga), and heavier (Er) than Zn, to see if there is any elemental segregation in the plume.

  13. Porous Nb-Ti based alloy produced from plasma spheroidized powder

    Science.gov (United States)

    Li, Qijun; Zhang, Lin; Wei, Dongbin; Ren, Shubin; Qu, Xuanhui

    Spherical Nb-Ti based alloy powder was prepared by the combination of plasma spheroidization and mechanical alloying. Phase constituents, microstructure and surface state of the powder, and pore characteristics of the resulting porous alloy were investigated. The results show that the undissolved W and V in the mechanically alloyed powder is fully alloyed after spheroidization, and single β phase is achieved. Particle size of the spheroidized powder is in the range of 20-110 μm. With the decrease of particle size, a transformation from typical dendrite solidification structure to fine cell microstructure occurs. The surface of the spheroidized powder is coated by a layer of oxides consisting mainly of TiO2 and Nb2O5. Probabilities of sinter-neck formation and particle coalescence increases with increasing sintering temperature. Porous skeleton with relatively homogeneous pore distribution and open pore channel is formed after vacuum sintering at 1700 °C, and the porosity is 32%. The sintering kinetic analysis indicates that grain boundary diffusion is the primary mass transport mechanism during sintering process.

  14. Development of an encapsulation method using plasma arc welding to produce iodine-125 seeds for brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Feher, Anselmo; Calvo, Wilson A.P.; Rostelato, Maria E.C.M.; Zeituni, Carlos A.; Somessari, Samir L.; Costa, Osvaldo L.; Moura, Joao A.; Moura, Eduardo S.; Souza, Carla D.; Rela, Paulo R., E-mail: afeher@ipen.b, E-mail: wapcalvo@ipen.b, E-mail: elisaros@ipen.b, E-mail: somessar@ipen.b, E-mail: olcosta@ipen.b, E-mail: esmoura@ipen.b, E-mail: cdsouza@ipen.b, E-mail: prela@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The prostate cancer, which is the second cause of death by cancer in men, overcome only by lung cancer is public health problem in Brazil. Brachytherapy is among the possible available treatments for prostate cancer, in which small seeds containing Iodine-125 radioisotope are implanted into the prostate gland. The seed consists of a titanium sealed capsule with 0.8 mm external diameter and 4.5 mm length, containing a central silver wire with adsorbed Iodine-125. The Plasma Arc Welding (PAW) is one of the viable techniques for sealing process. The equipment used in this technique is less costly than in other processes, such as, Laser Beam Welding (LBW). The main purpose of this work was the development of an encapsulation method using PAW. The development of this work has presented the following phases: cutting and cleaning titanium tube, determination of the welding parameters, development of a titanium tube holding device for PAW, sealed sources validation according to ISO 2919 - Sealed Radioactive Sources - General Requirements and Classification, and metallographic assays. The developed procedure to seal Iodine-125 seeds using PAW has shown high efficiency, satisfying all the established requirements of ISO 2919. The results obtained in this work will give the possibility to establish a routine production process according to the orientations presented in resolution RDC 17 - Good Manufacturing Practices to Medical Products defined by the ANVISA - National Agency of Sanitary Surveillance. (author)

  15. Near-net-shape 95W-3.5Ni-1.5Fe thin-walled products produced by plasma spray forming

    International Nuclear Information System (INIS)

    Wang, Y.M.; Xiong, X.; Min, X.B.; Xie, L.; Zheng, F.

    2010-01-01

    Tungsten heavy alloy 95W-3.5Ni-1.5Fe (in wt.%) refractory metallic thin-walled products (diameter ≤100 mm, length ≤150 mm and wall thickness ≤5 mm) were produced using plasma spray forming (PSF) covered in argon atmosphere at a pressure of 1.01 x 10 5 Pa followed by vacuum liquid phase sintering at 1465, 1485 and 1500 deg. C for 90 min, respectively. A lamellar structure consisting of vertical columnar grains and some fine particles was found in PSF deposits. Relative density of the deposits was about 87.70% with poor mechanical property. Upon vacuum liquid phase sintering, their density and property have been improved significantly. The microstructures of PSF deposits before and after vacuum sintering were found to consist with tungsten and (Ni, Fe)-rich phase. Volume fraction of (Ni, Fe)-rich phase was decreased due to vaporization that occurred in plasma spraying and vacuum liquid phase sintering. Their fracture surfaces were dominated by intergranular rupture. The lamellar structure remained in the deposits during early stages of sintering (solid state sintering and initial of liquid phase sintering). Particle rearrangement and rapid densification of the deposits did not occur until the surface of tungsten particles being modified and changed into spheroids by solution and precipitation. In the end, the PSF deposits have been transformed from lamellar structure into two phase composites with dispersed spheroidal tungsten grains embedded in a continuous network of (Ni, Fe)-rich phase.

  16. Measurements of spatially resolved high resolution spectra of laser-produced plasmas. FY 83 annual report

    International Nuclear Information System (INIS)

    Feldman, U.

    1984-01-01

    A high resolution grazing incidence spectrograph, provided by the Naval Research Laboratory and the Goddard Space Flight Center, has been installed on the Omega laser facility of the Laboratory for Laser Energetics (LLE) at the University of Rochester. This 3 meter instrument, with a 1200 lines/mm grating blazed at 2 0 35', has produced extremely high quality spectra in the wavelength region 10 A to 100 A. Spectra have been obtained from glass microballoon targets that are coated with a variety of high-Z materials. Transitions from the Na-like and Ne-like ionization stages of Fe, Ni, Cu, and Kr have been identified

  17. Extended spectrum beta-lactamase-producing Escherichia coli forms filaments as an initial response to cefotaxime treatment

    DEFF Research Database (Denmark)

    Kjeldsen, Thea S. B.; Sommer, Morten Otto Alexander; Olsen, John E.

    2015-01-01

    Background: beta-lactams target the peptidoglycan layer in the bacterial cell wall and most beta-lactam antibiotics cause filamentation in susceptible Gram-negative bacteria at low concentrations. The objective was to determine the initial morphological response of cephalosporin resistant CTX-M-1......-producing E. coli to cefotaxime and to determine whether the response depended on the growth phase of the bacterium and the concentration of antibiotic. Results: Two antibiotic resistant strains carrying bla(CTX-M-1) on the chromosome and on an IncI1 plasmid and three sensitive strains were used...... to cefotaxime. The filament formation was restricted to early growth phases and the time the cells grew as filaments was antibiotic concentration dependent. This indicates that antibiotic resistant E. coli undergo the same morphological changes as sensitive bacteria in the presence of beta-lactam antibiotic...

  18. Tribological properties of nitrogen-containing amorphous carbon film produced by dc plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Zhang Wei; Wazumi, Koichiro; Tanaka, Akihiro; Koga, Yoshinori

    2003-01-01

    The nitrogen-contained amorphous carbon (a-C:N) films were deposited in a dc plasma chemical vapor deposition system with different substrate bias voltages. The structural, mechanical, and tribological properties of the a-C:N films were investigated. The influence of the bias voltage on the tribological behaviors of the a-C:N films was evaluated under various environments (dry air, O 2 , N 2 , and vacuum) using a ball-on-disk friction tester. It showed that the sp 3 C and hydrogen concentration of the a-C:N films decreases with increasing the bias voltage. However, the nitrogen concentration increases with increasing the bias voltage. As a result, the hardness and internal stress decrease and the critical load for fracturing increases as the substrate bias increases. For the tribological properties of the a-C:N films, the friction coefficient of the films slightly decreases in the environments of N 2 , O 2 , or dry air, but increases slightly in the vacuum environment by increasing the bias voltage. It indicates that the incorporated nitrogen in the a-C:N films would decrease the friction coefficient of the films in N 2 or O 2 environments, but slightly increases the friction coefficient of the films in a vacuum. The excellent wear resistance of the a-C:N films, in the level of 10 -9 -10 -8 mm 3 /Nm, can be observed in N 2 , vacuum, and dry air environments. In addition, the effect of the bias voltage on the wear rate of the a-C:N films becomes less obvious by nitrogen incorporation. So, we suggest the incorporated nitrogen, which bonded to carbon and restrained the increase of the fraction of sp 2 C-C, would restrain the wear of the a-C:N films in different environments, especially in dry air

  19. Erosion resistance and adhesion of composite metal/ceramic coatings produced by plasma spraying

    International Nuclear Information System (INIS)

    Ramm, D.A.J.; Hutchings, I.M.; Clyne, T.W.

    1993-01-01

    Ceramic coatings can exhibit greater erosion resistance than most metallic coatings. Such coatings are conveniently produced by thermal spraying. Unfortunately, thermally sprayed ceramic coatings often exhibit poor adhesion, partly as a consequence of the development of residual stresses during spraying and subsequent cooling. Composite coatings have been studied using aluminium/alumina deposits on steel substrates. The incorporation of ceramics within a ductile matrix has potential for sharply reducing the erosive wear at high erodent impact angles, whilst retaining the good erosion resistance of ceramics at low angles. It is shown that the proportion of metal and ceramic at the free surface can be specified so as to optimise the erosion resistance. Experiments have also been carried out on the resistance of the coatings to debonding during four-point bending of the coated substrate. Progress is being made towards the tailoring of composition profiles in graded coatings so as to optimise the combination of erosion resistance and adhesion. (orig.)

  20. Stabilization of Rayleigh-Taylor instability due to the spontaneous magnetic field in laser produced plasma

    International Nuclear Information System (INIS)

    Ogasawara, Masatada; Takita, Masami.

    1981-08-01

    Spontaneous magnetic fields due to the temperature gradient nabla T 0 produced by a focussed laser beam on one point of a pellet are taken into account in deriving the dispersion relation of Rayleigh-Taylor instability. Growth rate γ decreases with time. Density fluctuation with wavelength shorter than 1.5(R/L sub(T)) x (n sub(s)/n 0 )sup(1/2) μm is remarkably stabilized, where R, L sub(T), n sub(s) and n 0 are the radius of a pellet, L sub(T)sup(-1) = + nabla T 0 /T 0 + , number densities of solid and the pellet. Validity condition of the theory is γt 0 >> 1 or in another form R >> L, where t 0 is the time of thermal expansion of a pellet and L -1 = + nabla n 0 /n 0 + . (author)

  1. Comparison of the initial orthodontic force systems produced by a new lingual bracket system and a straight-wire appliance.

    Science.gov (United States)

    Fuck, Lars-Michael; Wiechmann, Dirk; Drescher, Dieter

    2005-09-01

    Over the last few years, lingual appliances have become an established orthodontic treatment technique. Many studies have concentrated on various esthetic aspects, on laboratory and clinical procedures, and on patient comfort and compliance. The orthodontic force systems of these appliances, however, have not yet been investigated. The aim of this study was thus to determine the forces and moments produced by a new lingual bracket system during the leveling phase of orthodontic treatment and to compare those with the corresponding force system of a labial straight-wire appliance. The intra-oral situation of ten patients undergoing orthodontic treatment was replicated in measurement casts fitted with lingual and labial brackets. Special care was taken to precisely reproduce each patient's interbracket geometry. We measured each tooth's force systems as generated by a leveling arch inserted into the lingual and labial brackets. The resulting force systems of both appliances were found to be quite similar with regard to the magnitude of most force and moment components. Only the first molars were subjected to considerably greater single forces with the lingual appliance. Tipping moments were found to be significantly smaller with the lingual technique, whereas the rotational moments were significantly smaller with the labial appliance. All in all we noted significant differences between the two techniques only in certain areas which upon closer examination were distributed over only a few tooth types. The initial force systems produced by the new lingual bracket system proved to be comparable with those delivered by a conventional straight-wire appliance. The actual levels of forces and moments, however, were found in certain cases to be too heavy with both techniques. We therefore recommend the development of leveling wires producing considerably lighter forces and moments.

  2. Controlled treatment of primary hypertension with propranolol and spironolactone. A crossover study with special reference to initial plasma renin activity.

    Science.gov (United States)

    Karlberg, B E; Kågedal, B; Tegler, L; Tolagen, K; Bergman, B

    1976-03-31

    Twenty-seven patients with hypertension were randomly allocated to a 10 month crossover study. Treatment consisted of spironolactone (200 mg/day for 2 months), propranolol (320 mg/day for 2 months) and combined administration of both drugs at half the dosage. Between treatment periods placebo was given for 2 months. Fourteen patients were previously untreated. The average pretreatment blood pressure for the entire group was 188/114 +/- 16/7(mean +/- standard deviation) mm Hg supine and 188/118 +/- 20/9 mm Hg standing. Both spironolactone and propranolol reduced blood pressure significantly in both the supine and standing positions. Upright plasma renin activity was determined by radioimmunoassay of angiotensin I. The average initial level was 1.9 +/- 1.2 (range 0.4 to 5.0) ng/ml/hr. There was a close correlation between plasma renin activity and the effects of the drugs: With increasing renin level the response to propranolol was better whereas the opposite was true for spironolactone. The combination of spironolactone and propranolol decreased the blood pressure still further in the supine and standing positions, irrespective of initial plasma renin activity. All patients achieved a normal supine pressure. Blood pressure and plasma renin activity returned toward pretreatment values during placebo administration. It is concluded that pretreatment levels of plasma renin activity can predict the antihypertensive response to propranolol and spironolactone. The combination of the two drugs, which have different modes of action, will effectively reduce blood pressure in hypertension. The results support the concept that the renin-angiotensin-aldo-sterone system may be involved in primary hypertension.

  3. Reaction pathways of producing and losing particles in atmospheric pressure methane nanosecond pulsed needle-plane discharge plasma

    Science.gov (United States)

    Zhao, Yuefeng; Wang, Chao; Li, Li; Wang, Lijuan; Pan, Jie

    2018-03-01

    In this work, a two-dimensional fluid model is built up to numerically investigate the reaction pathways of producing and losing particles in atmospheric pressure methane nanosecond pulsed needle-plane discharge plasma. The calculation results indicate that the electron collisions with CH4 are the key pathways to produce the neutral particles CH2 and CH as well as the charged particles e and CH3+. CH3, H2, H, C2H2, and C2H4 primarily result from the reactions between the neutral particles and CH4. The charge transfer reactions are the significant pathways to produce CH4+, C2H2+, and C2H4+. As to the neutral species CH and H and the charged species CH3+, the reactions between themselves and CH4 contribute to substantial losses of these particles. The ways responsible for losing CH3, H2, C2H2, and C2H4 are CH3 + H → CH4, H2 + CH → CH2 + H, CH4+ + C2H2 → C2H2+ + CH4, and CH4+ + C2H4 → C2H4+ + CH4, respectively. Both electrons and C2H4+ are consumed by the dissociative electron-ion recombination reactions. The essential reaction pathways of losing CH4+ and C2H2+ are the charge transfer reactions.

  4. An ecotoxic risk assessment of residue materials produced by the plasma pyrolysis/vitrification (PP/V) process.

    Science.gov (United States)

    Lapa, N; Santos, Oliveira J F; Camacho, S L; Circeo, L J

    2002-01-01

    Plasma is the fourth state of matter, following the three states of solid, liquid and gas. Experience has amply demonstrated that solids exposed to the oxygen-deficient plasma flame are converted to liquid, and liquid exposed to the same flame is converted to gas. A low amount of vitrified solid residue material usually remains at the end of this process. Plasma pyrolysis/vitrification (PP/V) has been demonstrated as a safe, efficient, cost-effective technology for the treatment of wastes, including hazardous wastes. Besides the low amounts of gaseous byproducts that PP/V produces, the solid vitrified residue presents a low leachability of pollutants. Studies have been performed in many countries in order to assess the leachability of chemical substances. But from the results of identified studies, none has reported results on the ecotoxicological properties of the leachates. The aim of this study was to contribute to the assessment of ecotoxic risk of four different vitrified materials. Vitrified samples of contaminated soils, municipal solid wastes, and incinerator bottom ashes were submitted to the European leaching pre-standard test number prEN 12457-2. The leachates were analyzed for 22 chemical parameters. The biological characterization comprised the assessment of bioluminescence inhibition of Photobacterium phosphoreum bacterium, growth inhibition of Pseudokirchneriella subcapitata algae and the germination inhibition of Lactuca sativa vegetable. The chemical and ecotoxicological results were analyzed according to the French proposal of Criteria on the Evaluation Methods of Waste Toxicity (CEMWT) and a Toxicity Classification System (TCS). The chemical and ecotoxicological results indicated a low leachability of pollutants and a low toxicity level of leachates. All samples studied were as below the TCS class 1 level (no significant toxicity observed) and as non-ecotoxic for CEMWT. Therefore, the environmental ecotoxic risk of the analyzed vitrified samples

  5. Characterization of an ion beam produced by extraction and acceleration of ions from a wire plasma source

    International Nuclear Information System (INIS)

    Gueroult, R.

    2011-09-01

    In this study we first model a DC low pressure wire plasma source and then characterize the properties of an ion gun derived from the plasma source. In order to study the properties of the derived ion gun, we develop a particle-in-cell code fitted to the modelling of the wire plasma source operation, and validate it by confrontation with the results of an experimental study. In light of the simulation results, an analysis of the wire discharge in terms of a collisional Child-Langmuir ion flow in cylindrical geometry is proposed. We interpret the mode transition as a natural reorganization of the discharge when the current is increased above a threshold value which is a function of the discharge voltage, the pressure and the inter-electrodes distance. In addition, the analysis of the energy distribution function of ions impacting the cathode demonstrates the ability to extract an ion beam of low energy spread around the discharge voltage assuming that the discharge is operated in its high pressure mode. An ion source prototype allowing the extraction and acceleration of ions from the wire source is then proposed. The experimental study of such a device confirms that, apart from a shift corresponding to the accelerating voltage, the acceleration scheme does not spread the ion velocity distribution function along the axis of the beam. It is therefore possible to produce tunable energy (0 - 5 keV) ion beams of various ionic species presenting limited energy dispersion (∼ 10 eV). The typical beam currents are about a few tens of micro-amperes, and the divergence of such a beam is on the order of one degree. A numerical modelling of the ion source is eventually conducted in order to identify potential optimizations of the concept. (author)

  6. Antibody-integrated and functionalized graphite-encapsulated magnetic beads, produced using ammonia gas plasma technology, for capturing Salmonella.

    Science.gov (United States)

    Sakudo, Akikazu; Chou, Han; Nagatsu, Masaaki

    2015-03-01

    Salmonella spp. is the single and most important causative agent of foodborne infections, especially involving foods such as eggs, milk and meat. To prevent infection, a reliable surveillance system is required that can quickly and sensitively detect Salmonella. Here, we describe the development of antibody-integrated magnetic beads that are functionalized by a novel strategy using ammonia gas plasma. Ammonia plasma, produced by a radio frequency (RF) power supply, was allowed to react with the surface of graphite-encapsulated magnetic beads, resulting in the introduction of amino groups. An anti-Salmonella antibody was then anchored by sulfide groups present on the protein surface to the amino groups of the magnetic beads via N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP). The potential usefulness of these magnetic beads for capturing Salmonella was examined as follows. The beads were incubated with Salmonella in liquid medium and then separated from the supernatant by applying a magnetic field. After thorough washing, adsorption of Salmonella to the beads was confirmed by immunochromatography, polymerase chain reaction and a direct culture assay. Our findings indicate that the capture and concentration of Salmonella using the antibody-integrated magnetic beads was more efficient than commercial Dynabeads® anti-Salmonella, which are conventionally used for concentrating Salmonella from liquid cultures. We believe this novel bead technology will contribute to the enhanced detection of Salmonella. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Comments on pulses of characteristic energy produced in solar flare detonations and its possible application to other astrophysical plasmas

    International Nuclear Information System (INIS)

    Kaufmann, P.

    1977-01-01

    A qualitative discussion of physical conditions at neutral sheets was developed in an attempt to explain the repetitive pulsed energy-production mechanism, which has been suggested for solar flares. A characteristic energy per pulse appears to depend critically on the magnetic field strength and dipole length applied to a high temperature plasma, and seem to be regulated by discrete characteristic relative changes in the magnetic moment, following Syrovatskii's model. Discrete energy pulses are produced when neutral sheet thickness approaches to critical values, proportional to the characteristic relative changes in the magnetic moment. Repetition of pulses may occur in multi-sheet configurations as magnetically complex active centres, or at a single sheet where the total system energy change exceeds the critical conditions. The time-scale of the pulsed energy release may be explained by the tearing mode instability, and the repetition time-scale might be understood by the Sweet mechanism in limit conditions. The mechanism might have attractive applications in other high temperature astrophysical plasmas. An empirical relation is derived for pulses' energy prediction, in orders of magnitude, and some possible tests were suggested. An attempt was made to interpret soft γ-ray events of cosmic origin. (Auth.)

  8. Comments on pulses of characteristic energy produced in solar flare detonations and its possible application to other astrophysical plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, P [Universidade Mackenzie, Sao Paulo (Brazil). Centro de Radio-Astronomia e Astrofisica

    1977-06-01

    A qualitative discussion of physical conditions at neutral sheets was developed in an attempt to explain the repetitive pulsed energy-production mechanism, which has been suggested for solar flares. A characteristic energy per pulse appears to depend critically on the magnetic field strength and dipole length applied to a high temperature plasma, and seem to be regulated by discrete characteristic relative changes in the magnetic moment, following Syrovatskii's model. Discrete energy pulses are produced when neutral sheet thickness approaches to critical values, proportional to the characteristic relative changes in the magnetic moment. Repetition of pulses may occur in multi-sheet configurations as magnetically complex active centres, or at a single sheet where the total system energy change exceeds the critical conditions. The time-scale of the pulsed energy release may be explained by the tearing mode instability, and the repetition time-scale might be understood by the Sweet mechanism in limit conditions. The mechanism might have attractive applications in other high temperature astrophysical plasmas. An empirical relation is derived for pulses' energy prediction, in orders of magnitude, and some possible tests were suggested. An attempt was made to interpret soft ..gamma..-ray events of cosmic origin.

  9. Formation of metal nanoparticles of various sizes in plasma plumes produced by Ti:sapphire laser pulses

    International Nuclear Information System (INIS)

    Chakravarty, U.; Naik, P. A.; Mukherjee, C.; Kumbhare, S. R.; Gupta, P. D.

    2010-01-01

    In this paper, an experimental study on generation of nanoparticle various sizes using Ti:sapphire laser pulses, is reported. Nanoparticle formation in plasma plumes of metals like silver and copper, expanding in vacuum, has been studied using stretched pulses of 300 ps duration [subnanoseconds (sub-ns)] from a Ti:sapphire laser. It has been compared with the nanoparticle formation (of the same materials) when compressed pulses of 45 fs duration were used under similar focusing conditions. Nanoparticle formation is observed at intensities as high as 2x10 16 W/cm 2 . The structural analysis of the nanoparticle deposition on a silicon substrate showed that, using 45 fs pulses, smaller nanoparticles of average size ∼20 nm were generated, whereas on using the sub-ns pulses, larger particles were produced. Also, the visible light transmission and reflection from the nanoparticle film of Ag on glass substrate showed surface plasmon resonance (SPR). The SPR curves of the films of nanoparticles deposited by femtosecond pulses were always broader and reflection/transmission was always smaller when compared with the films formed using the sub-ns pulses, indicating smaller size particle formation by ultrashort pulses. Thus, it has been demonstrated that variation in the laser pulse duration of laser offers a simple tool for varying the size of the nanoparticles generated in plasma plumes.

  10. Coercivity of Nd-Fe-B hot-deformed magnets produced by the spark plasma sintering method

    Directory of Open Access Journals (Sweden)

    Tetsuji Saito

    2017-05-01

    Full Text Available The effects of Nd-Cu alloy powder addition on the microstructures and magnetic properties of Nd-Fe-B hot-deformed magnets produced by the spark plasma sintering (SPS method were investigated. The addition of a small amount of Nd-Cu alloy powder, up to 2%, significantly increased the coercivity of the Nd-Fe-B hot-deformed magnets without deteriorating the crystallographic alignment of the Nd2Fe14B phase. The Nd-Fe-B hot-deformed magnet with 2% Nd-Cu alloy powder had the same remanence value as the Nd-Fe-B hot-deformed magnet without Nd-Cu alloy powder addition, but the magnet with 2% Nd-Cu alloy powder exhibited higher coercivity and a higher maximum energy product than the magnet without Nd-Cu alloy powder addition.

  11. Electric wind produced by surface plasma actuators: a new dielectric barrier discharge based on a three-electrode geometry

    International Nuclear Information System (INIS)

    Moreau, Eric; Sosa, Roberto; Artana, Guillermo

    2008-01-01

    Active flow control is a rapidly developing topic because the associated industrial applications are of immense importance, particularly for aeronautics. Among all the flow control methods, such as the use of mechanical flaps or wall jets, plasma-based devices are very promising devices. The main advantages of such systems are their robustness, their simplicity, their low-power consumption and that they allow a real-time control at high frequency. This paper deals with an experimental study about the electric wind produced by a surface discharge based on a three-electrode geometry. This new device is composed of a typical two-electrode surface barrier discharge excited by an AC high voltage, plus a third electrode at which a DC high voltage is applied in order to extend the discharge region and to accelerate the ion drift velocity. In the first part the electrical current of these different surface discharges is presented and discussed. This shows that the current behaviour depends on the DC component polarity. The second part is dedicated to analysing the electric wind characteristics through Schlieren visualizations and to measuring its time-averaged velocity with a Pitot tube sensor. The results show that an excitation of the electrodes with an AC voltage plus a positive DC component can significantly modify the topology of the electric wind produced by a single DBD. In practice, this DC component allows us to increase the value of the maximum induced velocity (up to +150% at a few centimetres downstream of the discharge) and the plasma extension, to enhance the depression occurring above the discharge region and to increase the discharge-induced mass flow rate (up to +100%), without increasing the electrical power consumption

  12. Initial design for an experimental investigation of strongly coupled plasma behavior in the ATLAS facility

    CERN Document Server

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

    1999-01-01

    Summary form only given. Atlas is a high current (~30 MA peak, with a current risetime ~4.5 mu 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 (~2000 T), high strain and strain rates ( epsilon >200, d epsilon /dt~10/sup 4/ to 10/sup 6/ s/sup -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 (~1 eV) plasma by ohmic heating of a conducting material of interest such as titanium. This target plasma will be compressed against a central column conta...

  13. Heating of a dense plasma with an intense relativistic electron beam: initial observations

    International Nuclear Information System (INIS)

    Montgomery, M.D.; Parker, J.V.; Riepe, K.B.; Sheffield, R.L.

    1981-01-01

    A dense (approx. 10 17 cm -3 ) plasma has been heated via the relativistic two-stream instability using a 3 MeV, intense (5 x 10 5 A/cm 2 ) electron beam. Evidence for heating has been obtained with diamagnetic loops, thin-foil witness plates, and a 2-channel, broad-band soft x-ray detector. Measurements of energy loss from the beam using calorimetry techniques have been attempted. The measured strong dependence of heating on beam transverse temperature and the very short interaction length ( 100 ns after the beam pulse are consistent with a plasma temperature <150 eV and line emission near 80 to 90 eV

  14. Molecular Classification and Pharmacogenetics of Primary Plasma Cell Leukemia: An Initial Approach toward Precision Medicine.

    Science.gov (United States)

    Simeon, Vittorio; Todoerti, Katia; La Rocca, Francesco; Caivano, Antonella; Trino, Stefania; Lionetti, Marta; Agnelli, Luca; De Luca, Luciana; Laurenzana, Ilaria; Neri, Antonino; Musto, Pellegrino

    2015-07-30

    Primary plasma cell leukemia (pPCL) is a rare and aggressive variant of multiple myeloma (MM) which may represent a valid model for high-risk MM. This disease is associated with a very poor prognosis, and unfortunately, it has not significantly improved during the last three decades. New high-throughput technologies have allowed a better understanding of the molecular basis of this disease and moved toward risk stratification, providing insights for targeted therapy studies. This knowledge, added to the pharmacogenetic profile of new and old agents in the analysis of efficacy and safety, could contribute to help clinical decisions move toward a precision medicine and a better clinical outcome for these patients. In this review, we describe the available literature concerning the genomic characterization and pharmacogenetics of plasma cell leukemia (PCL).

  15. Plasma Assisted Ignition and Combustion at Low Initial Gas Temperatures: Development of Kinetic Mechanism

    Science.gov (United States)

    2016-10-05

    voltage J. Phys. D: Appl. Phys. 36 2683 [25] Soloviev V, Krivtsov V 2009 SDBD discharge modelling for aerodynamic applications J. Phys. D: Appl. Phys...effects. Plasma Sources Sci. Technol. 18 034018 (13pp). [14] Soloviev V, Krivtsov V. 2009. Surface barrier discharge modelling for aerodynamic applications...Lempert W and Gundersen MA. 2012. Vi- brational and rotational CARS measurements of nitrogen in afterglow of streamer discharge in atmospheric

  16. Partnership in Knowledge Creation: Lessons Learned from a Researcher-Policy Actor Partnership to Co-Produce a Rapid Appraisal Case Study of South Australia's Social Inclusion Initiative

    Science.gov (United States)

    Newman, Lareen; Biedrzycki, Kate; Patterson, Jan; Baum, Fran

    2011-01-01

    This paper describes a partnership between researchers and policy actors that was developed within a short timeframe to produce a rapid appraisal case study of a government policy initiative--South Australia's "Social Inclusion Initiative"--for the Social Exclusion Knowledge Network of the international Commission on Social Determinants…

  17. Atmospheric pressure plasma produced inside a closed package by a dielectric barrier discharge in Ar/CO2 for bacterial inactivation of biological samples

    International Nuclear Information System (INIS)

    Chiper, A S; Chen, W; Stamate, E; Mejlholm, O; Dalgaard, P

    2011-01-01

    The generation and evaluation of a dielectric barrier discharge produced inside a closed package made of a commercially available packaging film and filled with gas mixtures of Ar/CO 2 at atmospheric pressure is reported. The discharge parameters were analysed by electrical measurements and optical emission spectroscopy in two modes of operation: trapped gas atmosphere and flowing gas atmosphere. Gas temperature was estimated using the OH(A-X) emission spectrum and the rotational temperature reached a saturation level after a few minutes of plasma running. The rotational temperature was almost three times higher in the Ar/CO 2 plasma compared with an Ar plasma. The efficiency of the produced plasma for the inactivation of bacteria on food inside the closed package was investigated.

  18. Ionic regulation of the plasma membrane potential of rainbow trout (Salmo gairdneri) spermatozoa: Role in the initiation of sperm motility

    International Nuclear Information System (INIS)

    Gatti, J.L.; Billard, R.; Christen, R.

    1990-01-01

    The ionic dependence of the trout sperm plasma membrane potential was analysed by measuring the accumulation of the lipophilic ions 3 H-tetraphenylphosphonium (TPP) and 14 C-thiocyanate (SCN) following dilution in artificial media isotonic to the seminal fluid. Our data showed that the trout sperm plasma membrane has a mixed conductance: the plasma membrane potential is sensitive upon the transmembrane gradients of K+, Na+, and H+. This potential is negative (less than -40 mV) in a 125 mM choline chloride media (ChM) at pH 8.5. Replacement of choline by sodium has a small depolarizing effect. The membrane potential is about -15 mV in a 125 mM potassium chloride and falls near zero mV only if valinomycin is added. In ChM changing the external pH (pHe) greatly affects the membrane potential: its value rises from less than -40 mV at pHe 9.0 to -17 mV at pHe 5.0. This pH effect is observed also in presence of sodium or potassium. A decrease in the transmembrane proton gradient produced by increasing internal pH without changing pHe induces also a depolarisation of the plasma membrane. In the different media in which trout sperm remain immotile after dilution (media with [K+] greater than 20-40 mM or a pH less than 7.5) the plasma membrane is more depolarized than in media allowing motility, suggesting a relationship between the state of membrane polarization and the intracellular effectors of the axonemal movement

  19. Assessment of canine autologous platelet-rich plasma produced with a commercial centrifugation and platelet recovery kit.

    Science.gov (United States)

    Frye, Chris W; Enders, Andrew; Brooks, Marjory B; Struble, Angela M; Wakshlag, Joseph J

    2016-01-01

    To characterize the cellular composition (platelets, erythrocytes, and leukocytes) and confirm reproducibility of platelet enrichment, as well as determine the platelet activation status in the final product of a commercial platelet-rich plasma kit using canine blood. Venous blood from 20 sedated client-owned dogs was used to prepare platelet-rich plasma (PRP) from a commercial kit. Complete blood counts were performed to determine erythrocyte, leukocyte, and platelet numbers in both whole blood (WB) and resultant PRP. The WB and PRP samples from jugular (fast collection) and cephalic (slow collection) venipuncture were also compared. P-selectin externalization was measured in WB and PRP samples from 15 of 20 dogs. This commercial kit produced an average percent recovery in platelets of 64.7 ± 17.4; erythrocytes of 3.7 ± 0.8, and leukocytes of 31.6 ± 10.0. Neutrophil, monocyte, and lymphocyte percent recovery was 19.6 ± 7.2, 44.89 ± 19.8, and 57.5 ± 10.6, respectively. The recovery of platelets from jugular venipuncture (59.7 ± 13.6%) was lower than from cephalic recovery (68.8 ± 19.1%). The mean percent P-Selectin externalization for WB, PRP, and PRP with thrombin was 25.5 ± 30.9, 4.5 ± 6.4, and 90.6 ± 4.4 respectively. Cellular reproducibility of this kit was confirmed and platelets were concentrated within autologous serum. Additionally, measurements of P-selectin externalization showed that platelets are inactive in PRP unless stimulated to degranulate.

  20. Space-resolved XUV spectra of CVI and BV lines from a 10 ps KrF laser-produced plasma

    International Nuclear Information System (INIS)

    Iglesias, E.J.; Griem, H.R.; Elton, R.C.; Scott, H.

    1999-01-01

    We produced a plasma using highly focused ∼50 mJ, 10 ps pulses from a KrF laser on graphite and boron-carbide targets. We measured space-resolved (along the plasma axis) line profiles of Hydrogen-like and Helium-like Carbon and Boron resonance lines, using a crossed-slit, 1 m grazing-incidence spectrometer, with a spatial resolution ∼50 μm. Synthetic spectra generated with the atomic postprocessor CRETIN provided preliminary estimates of the plasma electron temperature and density. copyright 1999 American Institute of Physics

  1. Enzyme-labeled Antigen Method: Development and Application of the Novel Approach for Identifying Plasma Cells Locally Producing Disease-specific Antibodies in Inflammatory Lesions

    International Nuclear Information System (INIS)

    Mizutani, Yasuyoshi; Shiogama, Kazuya; Onouchi, Takanori; Sakurai, Kouhei; Inada, Ken-ichi; Tsutsumi, Yutaka

    2016-01-01

    In chronic inflammatory lesions of autoimmune and infectious diseases, plasma cells are frequently observed. Antigens recognized by antibodies produced by the plasma cells mostly remain unclear. A new technique identifying these corresponding antigens may give us a breakthrough for understanding the disease from a pathophysiological viewpoint, simply because the immunocytes are seen within the lesion. We have developed an enzyme-labeled antigen method for microscopic identification of the antigen recognized by specific antibodies locally produced in plasma cells in inflammatory lesions. Firstly, target biotinylated antigens were constructed by the wheat germ cell-free protein synthesis system or through chemical biotinylation. Next, proteins reactive to antibodies in tissue extracts were screened and antibody titers were evaluated by the AlphaScreen method. Finally, with the enzyme-labeled antigen method using the biotinylated antigens as probes, plasma cells producing specific antibodies were microscopically localized in fixed frozen sections. Our novel approach visualized tissue plasma cells that produced 1) autoantibodies in rheumatoid arthritis, 2) antibodies against major antigens of Porphyromonas gingivalis in periodontitis or radicular cyst, and 3) antibodies against a carbohydrate antigen, Strep A, of Streptococcus pyogenes in recurrent tonsillitis. Evaluation of local specific antibody responses expectedly contributes to clarifying previously unknown processes in inflammatory disorders

  2. Fasting plasma glucose as initial screening for diabetes and prediabetes in irish adults: The Diabetes Mellitus and Vascular health initiative (DMVhi).

    Science.gov (United States)

    Sinnott, Margaret; Kinsley, Brendan T; Jackson, Abaigeal D; Walsh, Cathal; O'Grady, Tony; Nolan, John J; Gaffney, Peter; Boran, Gerard; Kelleher, Cecily; Carr, Bernadette

    2015-01-01

    Type 2 diabetes has a long pre clinical asymptomatic phase. Early detection may delay or arrest disease progression. The Diabetes Mellitus and Vascular health initiative (DMVhi) was initiated as a prospective longitudinal cohort study on the prevalence of undiagnosed Type 2 diabetes and prediabetes, diabetes risk and cardiovascular risk in a cohort of Irish adults aged 45-75 years. Members of the largest Irish private health insurance provider aged 45 to 75 years were invited to participate in the study. already diagnosed with diabetes or taking oral hypoglycaemic agents. Participants completed a detailed medical questionnaire, had weight, height, waist and hip circumference and blood pressure measured. Fasting blood samples were taken for fasting plasma glucose (FPG). Those with FPG in the impaired fasting glucose (IFG) range had a 75gm oral glucose tolerance test performed. 122,531 subjects were invited to participate. 29,144 (24%) completed the study. The prevalence of undiagnosed diabetes was 1.8%, of impaired fasting glucose (IFG) was 7.1% and of impaired glucose tolerance (IGT) was 2.9%. Dysglycaemia increased among those aged 45-54, 55-64 and 65-75 years in both males (10.6%, 18.5%, 21.7% respectively) and females (4.3%, 8.6%, 10.9% respectively). Undiagnosed T2D, IFG and IGT were all associated with gender, age, blood pressure, BMI, abdominal obesity, family history of diabetes and triglyceride levels. Using FPG as initial screening may underestimate the prevalence of T2D in the study population. This study is the largest screening study for diabetes and prediabetes in the Irish population. Follow up of this cohort will provide data on progression to diabetes and on cardiovascular outcomes.

  3. Fasting plasma glucose as initial screening for diabetes and prediabetes in irish adults: The Diabetes Mellitus and Vascular health initiative (DMVhi.

    Directory of Open Access Journals (Sweden)

    Margaret Sinnott

    Full Text Available Type 2 diabetes has a long pre clinical asymptomatic phase. Early detection may delay or arrest disease progression. The Diabetes Mellitus and Vascular health initiative (DMVhi was initiated as a prospective longitudinal cohort study on the prevalence of undiagnosed Type 2 diabetes and prediabetes, diabetes risk and cardiovascular risk in a cohort of Irish adults aged 45-75 years.Members of the largest Irish private health insurance provider aged 45 to 75 years were invited to participate in the study.already diagnosed with diabetes or taking oral hypoglycaemic agents. Participants completed a detailed medical questionnaire, had weight, height, waist and hip circumference and blood pressure measured. Fasting blood samples were taken for fasting plasma glucose (FPG. Those with FPG in the impaired fasting glucose (IFG range had a 75gm oral glucose tolerance test performed.122,531 subjects were invited to participate. 29,144 (24% completed the study. The prevalence of undiagnosed diabetes was 1.8%, of impaired fasting glucose (IFG was 7.1% and of impaired glucose tolerance (IGT was 2.9%. Dysglycaemia increased among those aged 45-54, 55-64 and 65-75 years in both males (10.6%, 18.5%, 21.7% respectively and females (4.3%, 8.6%, 10.9% respectively. Undiagnosed T2D, IFG and IGT were all associated with gender, age, blood pressure, BMI, abdominal obesity, family history of diabetes and triglyceride levels. Using FPG as initial screening may underestimate the prevalence of T2D in the study population.This study is the largest screening study for diabetes and prediabetes in the Irish population. Follow up of this cohort will provide data on progression to diabetes and on cardiovascular outcomes.

  4. Using X-ray spectroheliograph technique for investigations of laser-produced plasma under interaction with strong magnetic field

    International Nuclear Information System (INIS)

    Faenov, A.; Dyakin, V.; Magunov, A.; Pikuz, T.; Skobelev, I.; Pikuz, S.; Pisarczyk, T.; Wolowski, J.; Zielinska, E.

    1996-01-01

    A dense jet of a plasma consisting of multiply charged ions was generated in the interaction of a laser plasma with a strong external axial magnetic field. It is shown that using the high-luminosity X-ray spectroheliograph technique allows to measure plasma emission spectra with 2-dimensional spatial resolution even in the cases when these spectra have small intensities. The X-ray spectroscopy and interferometry methods are used to measure plasma parameter distributions. The dependencies of N e (z) and T e (z) measured in this paper can be used to calculate the evolution of plasma ionization state during plasma expansion. The quasihomogeneous laser jet, which appears when a laser plasma interacts with an external magnetic field can be used not only to form an active medium of a short wavelength laser, but probably also to tackle the urgent problem of transport in a laser ion injector. (orig.)

  5. Using X-ray spectroheliograph technique for investigations of laser-produced plasma under interaction with strong magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Faenov, A. [MISDC of VNIIFTRI, Mendeleevo (Russian Federation); Dyakin, V. [MISDC of VNIIFTRI, Mendeleevo (Russian Federation); Magunov, A. [MISDC of VNIIFTRI, Mendeleevo (Russian Federation); Pikuz, T. [MISDC of VNIIFTRI, Mendeleevo (Russian Federation); Skobelev, I. [MISDC of VNIIFTRI, Mendeleevo (Russian Federation); Pikuz, S. [Rossijskaya Akademiya Nauk, Moscow (Russian Federation). Fizicheskij Inst.; Kasperczyk, A. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Pisarczyk, T. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Wolowski, J. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); Zielinska, E. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland)

    1996-08-01

    A dense jet of a plasma consisting of multiply charged ions was generated in the interaction of a laser plasma with a strong external axial magnetic field. It is shown that using the high-luminosity X-ray spectroheliograph technique allows to measure plasma emission spectra with 2-dimensional spatial resolution even in the cases when these spectra have small intensities. The X-ray spectroscopy and interferometry methods are used to measure plasma parameter distributions. The dependencies of N{sub e}(z) and T{sub e}(z) measured in this paper can be used to calculate the evolution of plasma ionization state during plasma expansion. The quasihomogeneous laser jet, which appears when a laser plasma interacts with an external magnetic field can be used not only to form an active medium of a short wavelength laser, but probably also to tackle the urgent problem of transport in a laser ion injector. (orig.).

  6. Surface Modification of Polystyrene with O Atoms Produced Downstream from an Ar/O2 Microwave Plasma

    Directory of Open Access Journals (Sweden)

    Xinyun Li

    2018-02-01

    Full Text Available Because discarded polystyrene (PS is little affected by degrading agents, PS was treated with a remote microwave (MW plasma discharge of an Ar/O2 mixture in the absence of radiation to increase wettability and introduce functional groups which make the waste more liable to degradation and useful for technological applications. X-ray photoelectron spectroscopy (XPS detected decreases in the aromatic sp2 and aliphatic sp3 carbons with treatment and, initially, increases in C–O and carbonyl groups, present in the formation of ethers, epoxides, alcohols, ketones and aldehydes. At longer treatment times, ester, O–C=O; carbonate-like, O–(C=O–O; and anhydride, O=C–O–C=O; moieties are observed with an overall oxygen saturation level of 23.6 ± 0.9 at% O. Atomic Force Microscopy (AFM measurements detected little change in surface roughness with treatment time. Advancing water contact angle decreased by ca. 50% compared to pristine PS indicating an increase in hydrophilicity because of oxidation. Washing the treated samples in deionized water decreased the oxygen concentrations at the saturation treatment times down to 18.6 ± 1 at% O due to the washing away of a weak boundary layer.

  7. Retrospective Evaluation of the Short-Term Sustainability of the Locally Grown Produce Initiative of the Hunger Prevention and Nutrition Assistance Program in New York State.

    Science.gov (United States)

    Allsopp, Marie A K; Hosler, Akiko S

    2018-03-27

    The Hunger Prevention and Nutrition Assistance Program (HPNAP) is a New York State Department of Health program. The HPNAP improves nutritional quality of food available at food banks, food pantries, soup kitchens, and emergency shelters through contractual relationships to fund the purchase, delivery, storage, and service of nutritious food. To determine whether a one-time fiscal stimulus of the Locally Grown Produce Initiative to HPNAP contractors in 2012-2013 would result in a short-term sustainable increase in the proportion of dollars spent on New York State Grown (NYSG) produce. Quasi-experimental, nonequivalent control group design. We analyzed New York State Department of Health administrative data regarding expenditures on all produce and NYSG produce by HPNAP contractors. New York State. The proportion of dollars spent on NYSG produce during 2011-2012 (preintervention) and 2013-2014 (postintervention) was compared between HPNAP food bank contractors (recipients of stimulus money, n = 8) and non-food bank contractors (nonrecipients, n = 34) using nonparametric methods. The HPNAP Locally Grown Produce Initiative was associated with an increased proportion of NYSG produce spending by food bank contractors that received a fiscal stimulus 1 year later. Upstate food banks had the largest increase (median 31.6%) among all HPNAP contractors. The results of this study revealed that the Locally Grown Produce Initiative fiscal stimulus had a positive, year-long and statewide effect on the proportion of expenditure on NYSG produce by food banks. We hope that the initial success seen in New York State may encourage other states to adopt similar initiatives in future.

  8. Crack initiation behaviors of metallic walls subjected to high heat flux expected at plasma disruption

    International Nuclear Information System (INIS)

    Yamazaki, Seiichiro; Uno, Masayoshi; Seki, Masahiro.

    1989-01-01

    Experimental and numerical studies were performed to investigate crack initiation behavior near a surface of stainless steel and tungsten when subjected to extremely high heat flux. The improved electron beam test facility was used as the heat source. Two-dimensional thermal and elasto-plastic stress analyses were also performed. From the results for stainless steel, micro-cracks about 0.1 mm deep only initiated in the resolidified layer along dendrites. No cracks propagated into the non-melted zone, and repeated heating of up to 20 times did not affect the depth and population of the cracks. According to the elasto-plastic stress analyses, no fatigue cracks were expected. Cracks with a depth of more than a few millimeters were observed in a tungsten plate. The cracks initiated at a boundary between heated and unheated areas. They grew into the non-melted zone, and curved towards the center part of the heated area. The elasto-plastic stress analyses indicated that the cracks were initiated due to the residual tensile strain after heated at the surface of the test specimen. When the heat flux was repeated, the cracks propagated and penetrated to the rear side of the test specimen in several repetition. (author)

  9. X-ray optical diagnostic of laser produced plasmas for nuclear fusion and X-ray lasers

    Energy Technology Data Exchange (ETDEWEB)

    Butzbach, R.

    2001-07-01

    In the present work, the conception, design and appliance of toroidally bent crystals for the X-ray optical diagnostics of laser produced plasmas is discussed. The first part of this work deals with the development, design and characterization of an X-Ray microscope for the observation of Rayleigh-Taylor instabilities, which act against the confinement and ignition of the fuel in the inertial confinement fusion process. The aim of the second part of the present work was the diagnostic of the lasing medium for amplified spontaneous emission close to the water window. For this purpose, an one-dimensionally (1-D) imaging X-ray spectrometer based on toroidally bent quartz crystals was developed for the observation of the Ni-like 4f-3d transition of Yb, Hf, Ta, and W ions, which should be related to the amplified 4d-4p emission, since the 4f niveau is very close to the 4d niveau. Thus, the 4f-3d transition can serve as an indicator for the population of the 4d niveau. (orig.)

  10. Raman enhancement on ultra-clean graphene quantum dots produced by quasi-equilibrium plasma-enhanced chemical vapor deposition.

    Science.gov (United States)

    Liu, Donghua; Chen, Xiaosong; Hu, Yibin; Sun, Tai; Song, Zhibo; Zheng, Yujie; Cao, Yongbin; Cai, Zhi; Cao, Min; Peng, Lan; Huang, Yuli; Du, Lei; Yang, Wuli; Chen, Gang; Wei, Dapeng; Wee, Andrew Thye Shen; Wei, Dacheng

    2018-01-15

    Graphene is regarded as a potential surface-enhanced Raman spectroscopy (SERS) substrate. However, the application of graphene quantum dots (GQDs) has had limited success due to material quality. Here, we develop a quasi-equilibrium plasma-enhanced chemical vapor deposition method to produce high-quality ultra-clean GQDs with sizes down to 2 nm directly on SiO 2 /Si, which are used as SERS substrates. The enhancement factor, which depends on the GQD size, is higher than conventional graphene sheets with sensitivity down to 1 × 10 -9  mol L -1 rhodamine. This is attributed to the high-quality GQDs with atomically clean surfaces and large number of edges, as well as the enhanced charge transfer between molecules and GQDs with appropriate diameters due to the existence of Van Hove singularities in the electronic density of states. This work demonstrates a sensitive SERS substrate, and is valuable for applications of GQDs in graphene-based photonics and optoelectronics.

  11. Fast and slow plasma components produced by the PALS facility - comparsion of interferometric and ion diagnostic measurements

    Czech Academy of Sciences Publication Activity Database

    Pisarcyk, T.; Badziak, J.; Kasperczuk, A.; Parys, P.; Wolowski, J.; Woryna, E.; Jungwirth, Karel; Králiková, Božena; Krása, Josef; Láska, Leoš; Mašek, Karel; Pfeifer, Miroslav; Rohlena, Karel; Skála, Jiří; Ullschmied, Jiří

    2002-01-01

    Roč. 52, Suppl. D (2002), D310-D316 ISSN 0011-4626. [Plasma Physics and Technology. Prague, 10.06.2002-13.06.2002] Grant - others:PALS/005(6)(XE) HPRI-CT-1999-00053 Institutional research plan: CEZ:AV0Z1010921 Keywords : laser plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.311, year: 2002

  12. Processing of ash and slag waste of heating plants by arc plasma to produce construction materials and nanomodifiers

    Science.gov (United States)

    Buyantuev, S. L.; Urkhanova, L. A.; Kondratenko, A. S.; Shishulkin, S. Yu; Lkhasaranov, S. A.; Khmelev, A. B.

    2017-01-01

    The resultsare presented of plasma processing slag and ash waste from coal combustion in heating plants. Melting mechanism of ashand slagraw material is considered by an electromagnetic technological reactor. The analysis was conducted of temperature and phase transformations of raw material when it is heated up to the melting point, and also determination of specific energy consumption by using a generalized model of the thermodynamic analysis of TERRA. The study of materials melting temperature conditions and plum of melt was carried with high-temperature thermal imaging method, followed by mapping and 3D-modeling of the temperature fields. The investigations to establish the principal possibilities of using slag waste of local coal as raw material for the production of mineral (ash and slag) fibers found that by chemical composition there are oxides in the following ranges: 45-65% SiO2; 10-25% Al2O3; 10-45% CaO; 5-10% MgO; other minerals (less than 5%). Thus, these technological wastes are principally suitable for melts to produce mineral wool by the plasma method. An analysis of the results shows the melting point of ash and slag waste - 1800-2000 °C. In this case the specific energy consumption of these processes keeps within the limits of 1.1-1.3 kW*h/kg. For comparison it should be noted that the unit cost of electricity in the known high-melting industrial installations 5-6 kW*h/kg. Upon melting ash and slag waste, which contains up to 2-5% of unburned carbon, carbon nanomaterials were discovered.in the form of ultrafine soot accumulating as a plaque on the water-cooled surfaces in the gas cleaning chamber. The process of formation of soot consists in sublimation-desublimation of part of carbon which is in ash and slag, and graphite electrode. Thus, upon melting of ash and slag in the electromagnetic reactor it is possible to obtain melt, and in the subsequent mineral high quality fiber, which satisfies the requirements of normative documents, and

  13. Comparative study of atmospheric pressure low and radio frequency microjet plasmas produced in a single electrode configuration

    International Nuclear Information System (INIS)

    Kim, Dan Bee; Rhee, J. K.; Gweon, B.; Moon, S. Y.; Choe, W.

    2007-01-01

    Microsize jet-type plasmas were generated in a single pin electrode structure source for two separate input frequencies of 50 kHz and 13.56 MHz in the ambient air. The copper pin electrode radius was 360 μm, and it was placed in a Pyrex tube with a radius of 3 mm for helium gas supply. Due to the input frequency difference, the generated plasmas showed distinct discharge characteristics for their plasma physical appearances, electrical properties, gas temperatures, and optical properties. Strengths and weaknesses of both plasmas were discussed for further applications

  14. Influence of target material on structure of the plasma outflow produced by a partly defocused laser beam

    Czech Academy of Sciences Publication Activity Database

    Kasperczuk, A.; Pisarczyk, T.; Kálal, M.; Ullschmied, Jiří; Krouský, Eduard; Mašek, Karel; Pfeifer, Miroslav; Rohlena, Karel; Skála, Jiří; Pisarczyk, P.

    2009-01-01

    Roč. 94, č. 8 (2009), 081501-1-081501-3 ISSN 0003-6951 R&D Projects: GA MŠk(CZ) LC528; GA MŠk(CZ) 7E08094 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z10100523 Keywords : plasma diagnostics * plasma jets * plasma production by laser Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.554, year: 2009 http://link.aip.org/link/?APPLAB/94/081501/1

  15. Rapid changes in plasma membrane protein phosphorylation during initiation of cell wall digestion

    International Nuclear Information System (INIS)

    Blowers, D.P.; Boss, W.F.; Trewavas, A.J.

    1988-01-01

    Plasma membrane vesicles from wild carrot cells grown in suspension culture were isolated by aqueous two-phase partitioning, and ATP-dependent phosphorylation was measured with [γ- 32 P]ATP in the presence and absence of calcium. Treatment of the carrot cells with the cell wall digestion enzymes, driselase, in a sorbitol osmoticum for 1.5 min altered the protein phosphorylation pattern compared to that of cells treated with sorbitol alone. Driselase treatment resulted in decreased phosphorylation of a band of M r 80,000 which showed almost complete calcium dependence in the osmoticum treated cells; decreased phosphorylation of a band of M r 15,000 which showed little calcium activation, and appearance of a new band of calcium-dependent phosphorylation at M r 22,000. However, protein phosphorylation was decreased. Adding driselase to the in vitro reaction mixture caused a general decrease in the membrane protein phosphorylation either in the presence or absence of calcium which did not mimic the in vivo response. Cells labeled in vivo with inorganic 32 P also showed a response to the Driselase treatment. An enzymically active driselas preparation was required for the observed responses

  16. X-ray spectrum emitted by a laser-produced cerium plasma in the 7.5 to 12 A wavelength range

    International Nuclear Information System (INIS)

    Doron, R.; Behar, E.; Fraenkel, M.; Mandelbaum, P.; Schwob, J.L.; Zigler, A.

    2001-01-01

    A highly stripped cerium (Z = 58) plasma is produced by irradiating a solid cerium target with an intense short laser pulse. The X-ray spectrum emitted from the plasma is recorded in the 7.5-12 A wavelength range using a flat RAP crystal spectrometer. Ab-initio calculations using the RELAC relativistic computer code, as well as isoelectronic trends deduced from previous works, together with spectra obtained under different laser beam focusing conditions, are all employed for the identification of the spectral lines and features emitted by various ions from Fe-like Ce 32+ to As-like Ce 25+ . The technique of comparing spectra obtained using different laser intensities is also employed to confirm or to resolve some ambiguous identifications of spectral features in the spectrum of a laser-produced lanthanum plasma studied in a previous work. (orig.)

  17. X-ray spectrum emitted by a laser-produced cerium plasma in the 7.5 to 12 A wavelength range

    Energy Technology Data Exchange (ETDEWEB)

    Doron, R.; Behar, E.; Fraenkel, M.; Mandelbaum, P.; Schwob, J.L.; Zigler, A. [Hebrew Univ., Jerusalem (Israel). Racah Inst. of Physics; Faenov, A.Ya.; Pikuz, T.A. [Multicharged Ion Spectra Data Center, VNIIFTRI, Mendeleevo (Russian Federation)

    2001-01-01

    A highly stripped cerium (Z = 58) plasma is produced by irradiating a solid cerium target with an intense short laser pulse. The X-ray spectrum emitted from the plasma is recorded in the 7.5-12 A wavelength range using a flat RAP crystal spectrometer. Ab-initio calculations using the RELAC relativistic computer code, as well as isoelectronic trends deduced from previous works, together with spectra obtained under different laser beam focusing conditions, are all employed for the identification of the spectral lines and features emitted by various ions from Fe-like Ce{sup 32+} to As-like Ce{sup 25+}. The technique of comparing spectra obtained using different laser intensities is also employed to confirm or to resolve some ambiguous identifications of spectral features in the spectrum of a laser-produced lanthanum plasma studied in a previous work. (orig.)

  18. Characterization of Electron Temperature and Density Profiles of Plasmas Produced by Nike KrF Laser for Laser Plasma Instability (LPI) Research

    Science.gov (United States)

    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 (λ = 248 nm , Δν ~ 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 (λ = 266 nm , Δt = 8 psec) beamlets (50 μm 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.

  19. Acceleration of protons in plasma produced from a thin plastic or aluminum target by a femtosecond laser

    International Nuclear Information System (INIS)

    Rosinski, M.; Badziak, J.; Parys, P.; Zaras-Szydlowska, A.; Ryc, L.; Makowski, J.; Torrisi, L.; Szydlowski, A.; Malinowska, A.; Kaczmarczyk, B.; Torrisi, A.

    2016-01-01

    The acceleration of protons in plasma produced from thin mylar (3.5 μ m) and aluminum (2 μm) targets by a 45-fs laser pulses with the energy of 400 mJ and the intensity of up to 10 19 W/cm 2 was investigated. Characteristics of forward-accelerated protons were measured by the time-of-flight method. In the measurements, special attention was paid to the dependence of proton beam parameters on the laser focus position (FP) in relation to the target surface which resulted in the intensity change within a factor of ∼ 10. It was observed that in the case of using the Mylar target, the dependence of both the maximum ( E pmax ) and the mean (( E p )) proton energy on |Δ x | is clearly non-symmetric with regard to the point where FP = 0 (the focal plane on the target surface) and highest proton energies are achieved when the focal plane is situated in front of the target. In particular, for the target with the thickness of 3.5 μ m E pmax reached 2.2 MeV for FP = +50 μm while for FP = 0 and FP = −100 μm the maximum proton energies reached only 1.6 MeV and 1.3 MeV, respectively. For the aluminum target of 2 μm thickness E p changed only within ∼ 40% and the highest proton energies reached 2.4 MeV.

  20. Multistage plasma initiation process by pulsed CO2 laser irradiation of a Ti sample in an ambient gas (He, Ar, or N2)

    Science.gov (United States)

    Hermann, J.; Boulmer-Leborgne, C.; Mihailescu, I. N.; Dubreuil, B.

    1993-02-01

    New experimental results are reported on plasma initiation in front of a titanium sample irradiated by ir (λ=10.6 μm) laser pulses in an ambient gas (He, Ar, and N2) at pressures ranging from several Torr up to the atmosphere. The plasma is studied by space- and time-resolved emission spectroscopy, while sample vaporization is probed by laser-induced fluorescence spectroscopy. Threshold laser intensities leading to the formation of a plasma in the vapor and in the ambient gases are determined. Experimental results support the model of a vaporization mechanism for the plasma initiation (vaporization-initiated plasma breakdown). The plasma initiation is described by simple numerical criteria based on a two-stage process. Theoretical predictions are found to be in a reasonable agreement with the experiment. This study provides also a clear explanation of the influence of the ambient gas on the laser beam-metal surface energy transfer. Laser irradiation always causes an important vaporization when performed in He, while in the case of Ar or N2, the interaction is reduced in heating and vaporization of some surface defects and impurities.