Science.gov

Sample records for plasma initiation produced

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

    SciTech Connect

    Yamaura, Michiteru

    2006-06-19

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

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

    PubMed

    Labaune, C; Baccou, C; Depierreux, S; Goyon, C; Loisel, G; Yahia, V; 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. PMID:24104859

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    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.

  4. Dependence of optimal initial density on laser parameters for multi-keV x-ray radiators generated by nanosecond laser-produced underdense plasma

    NASA Astrophysics Data System (ADS)

    Tu, Shao-yong; Yuan, Yong-teng; Hu, Guang-yue; Miao, Wen-yong; Zhao, Bin; Zheng, Jian; Jiang, Shao-en; Ding, Yong-kun

    2016-01-01

    Efficient multi-keV x-ray sources can be produced using nanosecond laser pulse-heated middle-Z underdense plasmas generated using gas or foam. Previous experimental results show that an optimal initial target density exists for efficient multi-keV x-ray emission at which the laser ionization wave is supersonic. Here we explore the influence of the laser intensity and the pulse duration on this optimal initial target density via a one-dimensional radiation hydrodynamic simulation. The simulation shows that the optimal initial density is sensitive to both the laser intensity and the pulse duration. However, the speed of the supersonic ionization wave at the end of the laser irradiation is always maintained at 1.5 to 1.7 times that of the ion acoustic wave under the optimal initial density conditions.

  5. Laser initiated, RF sustained air plasmas

    NASA Astrophysics Data System (ADS)

    Giar, Ryan; Scharer, John; Wiebold, Matt

    2010-11-01

    Measurements and analysis of air breakdown processes and plasma production by focusing 193 nm, 260 mJ, 10 MW high power laser radiation inside a 6 cm diameter helical RF coil. We observe quantum resonant multi-photon (REMPI)2 and collisional cascade laser ionization processes that produce high density (ne˜7 x 1016/cm^3) cylindrical seed plasmas at 760 Torr. The focused laser and associated shock wave produces a seed plasma for sustaining by the RF (1-10 kW, 0.5-1.5 s) pulse. Measurements of the helical RF antenna load impedance obtained by measuring the reflection coefficient with and without the laser pulse and 105 mm wave interferometer density and temperature measurements are made. They demonstrate that the laser formed seed plasma allows RF sustainment at higher initial air pressures (15-30 Torr) than with RF only initiation. Spectroscopic measurements of the plasma and comparison with the SPECAIR code are made to determine rotational and vibrational temperatures. Comparison of the experimental measurements of helical antenna plasma loading with the ANTENAII code will be made and discussed.

  6. APPARATUS FOR PRODUCING AND MANIPULATING PLASMAS

    DOEpatents

    Colgate, S.A.; Ferguson, J.P.; Furth, H.P.; Wright, R.E.

    1960-07-26

    An electrical pinch discharge apparatus is described for producing and manipulating high-temperature plasmas. The apparatus may be of either the linear or toroidal pinch discharge type. Arrangements are provided whereby stabilizing fields may be trapped in the plasma external to the main pinch discharge path and the boundary condition of the stabilizing field programed so as to stabilize the discharge or to promote instabilities in the discharge as desired. The produced plasmas may be employed for various purposes, and fusion neutrons have been produced with the apparatus.

  7. Conductivity of plasma produced from cluster explosions

    NASA Astrophysics Data System (ADS)

    Hay, Michael J.; Fisch, Nathaniel J.

    2013-10-01

    After ionization but before local thermal equilibrium (LTE), plasma characteristic parameters can deviate strongly from homogeneous Maxwellian estimates. This is especially true for dusty plasmas or plasmas formed from structured materials, such as aerogels and aerosols, which retain inhomogeneities on the scale length of the material structures. Plasma collective effects and bulk plasma characteristics, such as conductivity or transport, might then deviate from the those calculated on a near-LTE basis. We consider as an example plasma conductivity effects in plasma produced from the Coulomb explosion of small clusters. Work supported by DOE contract no. DE-AC02-09CH11466 and by NNSA grant no. DE-FG52-08NA28553.

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

    DOEpatents

    Clarke, John 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.

  9. Focused Laser Initiated RF Sustained High Pressure Air Plasmas

    NASA Astrophysics Data System (ADS)

    Li, Yan; Scharer, John

    2012-10-01

    Measurements and analysis of air breakdown processes and plasma production were done by focusing 193 nm, 300 mJ, 15 MW high power laser radiation inside a helical RF coil. We observe quantum resonant multi-photon and collisional cascade laser ionization processes that produce high density (ne˜5*10^15/cm^3) cylindrical seed plasmas. We installed an improved capacitive system that better matches the antenna impedance before plasma is produced, which increases the breakdown pressure from 20 to 60 torr with 5 kW incident RF power only. The focused laser and associated shock wave produces a plasma seed for sustaining by the RF (1-10 kW, 0.5-1.8 s) pulse. We find that triggering 20 ns multi-laser pulses at 20 Hz during one RF pulse increases the breakdown pressure from 70 to 85 torr single laser pulse. Measurements of the helical RF antenna plasma-loaded impedance are obtained by measuring the complex reflection coefficient with and without the laser pulse. Additional diagnostics are obtained with a 105 GHz interferometer to measure plasma density, collision frequency and electron temperature. Spectroscopic measurements of the plasma and comparison with the SPECAIR code are made to determine rotational and vibrational neutral gas temperatures. The results demonstrate that the laser formed seed plasma allows RF sustainment at higher initial air pressures than with RF only initiation.

  10. Laser-produced plasmas in medicine

    SciTech Connect

    Gitomer, S.J. ); Jones, R.D. . Applied Theoretical Physics Div.)

    1991-12-01

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

  11. Laser-produced plasmas in medicine

    SciTech Connect

    Gitomer, S.J.; Jones, R.D.

    1990-01-01

    The laser has found numerous applications in medicine, beginning with uses in ophthalmology in the 1960's. Today, lasers are used in tissue cutting, blood coagulation, photo-dynamic cancer therapy, arterial plaque removal, dental drilling, etc. In this paper, we examine those areas of laser medicine in which plasmas (ionized gases) are produced. In fact, the presence of a plasma is essential for the application at hand to succeed. We consider examples of the plasmas produced in ophthalmology (e.g., lens membrane destruction following cataract surgery), in urology and gastroenterology (e.g., kidney and gall stone ablation and fragmentation) and in cardiology and vascular surgery (e.g., laser ablation and removal of fibro-fatty and calcified arterial plaque). Experimental data are presented along with some results from computer simulations of the phenomena. Comments on future directions in these areas are included. 63 refs.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  13. Adventures in Laser Produced Plasma Research

    SciTech Connect

    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.

  14. Initial Cassini Plasma Observations at Saturn

    NASA Astrophysics Data System (ADS)

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

    2004-12-01

    The Cassini Plasma Spectrometer (CAPS) measures ion energy and mass from 1 eV to 50 keV and electron spectra from 1 eV to 28 keV. It thus fills in important gaps in earlier Voyager measurements of plasma energy and composition. This paper gives an overview of data taken during the first two Cassini orbits, including the closest approach to Saturn and the rings during the tour (1.3 S), and a close flyby of Titan (1250 km altitude), two passes through Saturn's inner magnetosphere (one at a moderate, 10-15o latitude height above the equatorial plane, and one crossing the equatorial plane at approximately 8 RS), and period of roughly 50 days of solar wind monitoring in conjunction with Cassini remote sensing of Saturn's aurora. Initial analysis shows the existence of H+, H2+ and/or He++}, N+, water group, and O2+ ions within Saturn's magnetosphere, the exact composition depending on location. Several distinctive regions of plasma have been identified including a cold ``ionosphere'' located over the rings, a region of quiescent, corotating plasma between approximately 2 RS and 6 RS, a region of highly disturbed plasma between 6 S and 14 S, containing numerous injection and/or local acceleration events, and a region of hot, very low density plasma outside approximately 14 S. We also anticipate being able to give an overview of observations of plasma in the proximity of Titan and its ionosphere.

  15. Surface modifications by plasma produced nanoparticles

    NASA Astrophysics Data System (ADS)

    Berndt, Johannes; Brault, Pascal

    2014-10-01

    Low temperature plasmas with their distinct non equilibrium character are a versatile tool for the production and subsequent deposition of nanoparticles. This contribution will focus on two aspects: on strategies to control the formation of nanoparticles in reactive low temperature plasmas and on the production and functionalization of nanoparticle- deposits. The importance of such nanoparticle-deposits will be discussed on the basis of two examples: the production of surfaces with switchable wetting properties and the decoration of surfaces with nanoparticles for fuel cell applications. The financial support of the European Commission under the FP7 Fuel Cells and Hydrogen Joint Technology Initiative Grant Agreement FP7-2012-JTI-FCH-325327 for the SMARTCat project is gratefully acknowledged.

  16. Producing Hydrogen by Plasma Pyrolysis of Methane

    NASA Technical Reports Server (NTRS)

    Atwater, James; Akse, James; Wheeler, Richard

    2010-01-01

    Plasma pyrolysis of methane has been investigated for utility as a process for producing hydrogen. This process was conceived as a means of recovering hydrogen from methane produced as a byproduct of operation of a life-support system aboard a spacecraft. On Earth, this process, when fully developed, could be a means of producing hydrogen (for use as a fuel) from methane in natural gas. The most closely related prior competing process - catalytic pyrolysis of methane - has several disadvantages: a) The reactor used in the process is highly susceptible to fouling and deactivation of the catalyst by carbon deposits, necessitating frequent regeneration or replacement of the catalyst. b) The reactor is highly susceptible to plugging by deposition of carbon within fixed beds, with consequent channeling of flow, high pressure drops, and severe limitations on mass transfer, all contributing to reductions in reactor efficiency. c) Reaction rates are intrinsically low. d) The energy demand of the process is high.

  17. Plasma treatment for producing electron emitters

    DOEpatents

    Coates, Don Mayo (Santa Fe, NM); Walter, Kevin Carl (Los Alamos, NM)

    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.

  18. Arc initiation in cathodic arc plasma sources

    DOEpatents

    Anders, Andre (Albany, CA)

    2002-01-01

    A "triggerless" arc initiation method and apparatus is based on simply switching the arc supply voltage to the electrodes (anode and cathode). Neither a mechanical trigger electrode nor a high voltage flashover from a trigger electrode is required. A conducting path between the anode and cathode is provided, which allows a hot spot to form at a location where the path connects to the cathode. While the conductive path is eroded by the cathode spot action, plasma deposition ensures the ongoing repair of the conducting path. Arc initiation is achieved by simply applying the relatively low voltage of the arc power supply, e.g. 500 V-1 kV, with the insulator between the anode and cathode coated with a conducting layer and the current at the layer-cathode interface concentrated at one or a few contact points. The local power density at these contact points is sufficient for plasma production and thus arc initiation. A conductive surface layer, such as graphite or the material being deposited, is formed on the surface of the insulator which separates the cathode from the anode. The mechanism of plasma production (and arc initiation) is based on explosive destruction of the layer-cathode interface caused by joule heating. The current flow between the thin insulator coating and cathode occurs at only a few contact points so the current density is high.

  19. Molybdenum disilicide composites produced by plasma spraying

    SciTech Connect

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

    1998-05-25

    The intermetallic compound, molybdenum disilicide (MoSi{sub 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{sub 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{sub 2}O{sub 3}, SiC, Si{sub 3}N{sub 4} and Mo{sub 5}Si{sub 3}. Laminate composites, in particular, have been shown to improve the damage tolerance of MoSi{sub 2} during high temperature melting operations. A review of research which as been performed at Los Alamos National Laboratory on plasma spraying of MoSi{sub 2}-based composites to improve low temperature fracture toughness, thermal shock resistance, high temperature strength and creep resistance will be discussed.

  20. Initial results on high enthalpy plasma generation in a magnetized coaxial source

    SciTech Connect

    Mayo, R.M.; Bourham, M.A.; Caress, R.W.; Black, D.C.; Glover, M.E.

    1994-11-01

    Initial investigation on high enthalpy plasma stream generation in the North Carolina State University Coaxial Plasma Source (CPS) facility is presented. Tenuous, yet high enthalpy, flows are produced from this Magnetized Coaxial plasma Gun (MCG) which allow laboratory study of plasma streams with a wide variety of applications. The applicability includes, but is not limited to, advanced thrusters for electric space propulsion, astrophysical jets and critical ionization phenomena, magnetic fusion compact toroid devices and tokamak fueling, large scale plasma etching and deposition, etc.

  1. Plasma Initiated Emulsion Polymerization of MMA

    NASA Astrophysics Data System (ADS)

    Li, Bi-tao; Sun, Qiu-shi; Li, Gang; Hou, Xiao-huai

    1999-12-01

    A study was made on plasma-initiated emulsion polymerization and kind of ultra-high molecular weight poly(methyl methacrylate) (PMMA) was obtained. The viscosity-averaged molecular weight M? of this PMMA is over 1107 in the measurement of viscosity by using Butanone as solvent. Its glass transition temperature Tg and flow temperature Tf measured by DSC are 132.8 C and 299.2 C respectively. The effects of reaction duration, radiation power and polymerization temperature on the conversion and the molecular weight of the products were also investigated. The results of these studies suggest that by way of initiated polymerization, the molecular weight of polymer are greatly enhanced.

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

    PubMed

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

    2014-09-01

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

  3. Microwave produced plasma in a Toroidal Device

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

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

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

    SciTech Connect

    Mishra, Anurag; Lee, Sehan; Yeom, Geun Y.

    2014-11-01

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

  5. METHOD OF INITIATING AND SUSTAINING AN ENERGETIC PLASMA FOR NEUTRON PRODUCTION

    DOEpatents

    Bell, P.R.; Mackin, R.J. Jr.; Simon, A.

    1961-08-22

    A method for producing an energetic plasma for neutron production and for faeling this plasma once it is formed is described. The plasma is initially fonmed as set forth in U. S. Patent No. 2,969,308. After the plasma is formed, cold neutral particles with an energy of at least 1 Kev are injected in a radial directinn and transverse to the axis of the device. These cold particles are substituted for the molecular ion injection and are used for fueling the plasma device on a continuous regulated basis in order to maintain a reaction temperature of about 60 Kev for producing neutrons. (AE C)

  6. Light source employing laser-produced plasma

    DOEpatents

    Tao, Yezheng; Tillack, Mark S

    2013-09-17

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

  7. Experiments on Initial Formation of Plasma Flow Switches.

    NASA Astrophysics Data System (ADS)

    Benage, John F., Jr.; Bowers, Richard; Oona, Hank; Wysocki, Fred; Broste, William B.; Harper, Ron; Roderick, Norm

    1996-11-01

    Plasma flow switches have been used to shorten the current pulse for inductive storage capacitor banks to implode plasmas for producing radiation.(J.H.Degnan, et.al., IEEE Trans. Plasma Sci., PS-15, 760(1987).)They consist of two components, an aluminum wire array and a plastic barrier film separated by a few mm. We have performed a series of experiments at Los Alamos to understand the sensitivity of the performance of plasma flow switches to their initial conditions. These experiments were done on two facilities, one a 250 kJ capacitor bank called the Colt facility with a maximum current of 1.0 MA in 2.5 microseconds. The other is the Pegasus II facility with a maximum current of 10 MA in a time of 4 microseconds. The overall performance of the switch as determined by the voltage developed was measured as a function of the mass of the switch, the distribution of the mass among the switch components, and the separation of the components. A preliminary understanding of the important parameters and the physical basis for their importance will be given. (This worked performed under the auspices of the Department of Energy.)

  8. Laser electron acceleration in the prepulse produced plasma corona

    NASA Astrophysics Data System (ADS)

    Andreev, N. E.; Povarnitsyn, M. E.; Pugachev, L. P.; Levashov, P. R.

    2015-11-01

    The generation of hot electrons at grazing incidence of a subpicosecond relativistic-intense laser pulse onto the plane solid target is analyzed for the parameters of the petawatt class laser systems. We study the preplasma formation on the surface of solid Al target produced by the laser prepulses with different time structure. For modeling of the preplasma dynamics we use a wide-range two-temperature hydrodynamic model. As a result of simulations, the preplasma expansion under the action of the laser prepulse and the plasma density profiles for different contrast ratios of the nanosecond pedestal are found. These density profiles were used as the initial density distributions in 3-D PIC simulations of electron acceleration by the main P-polarized laser pulse. Results of modeling demonstrate the substantial increase of the characteristic energy and number of accelerated electrons for the grazing incidence of a subpicosecond intense laser pulse in comparison with the laser-target interaction at normal incidence.

  9. Laser produced plasma for efficient extreme ultraviolet light sources

    SciTech Connect

    Donnelly, Tony; Cummins, Thomas; O' Gorman, Colm; Li Bowen; Harte, Colm S.; O'Reilly, Fergal; Sokell, Emma; Dunne, Padraig; O'Sullivan, Gerry

    2012-05-25

    Extreme ultraviolet emission from laser produced plasma and their relevance to EUV source development is discussed. The current state of the field for Sn LPP sources operating at 13.5 nm is described and initial results are given for EUV emission from CO{sub 2} laser irradiation of a bulk Sn target. A maximum conversion efficiency of 1.7% has been measured and the influence of the CO{sub 2} laser temporal profile on the CE is discussed. A double pulse irradiation scheme is shown to increase CE up to a maximum value of 2.1% for an optimum prepulse - pulse delay of 150 ns. The emergence of a new EUVL source wavelength at 6.7 nm based on Gd and Tb LPPs has been outlined. An initial experiment investigating picosecond laser irradiation as a means to produce strong 6.7 nm emission from a Gd{sub 2}O{sub 3} target has been performed and verified.

  10. Ablation and plasma emission produced by dual femtosecond laser pulses

    SciTech Connect

    Singha, Sima; Gordon, Robert J.; Hu Zhan

    2008-12-01

    Pairs of 80 fs, 800 nm laser pulses were used to ablate Si, Cu, and CaF{sub 2} in air. The spectrally resolved plasma emission was measured as a function of laser fluence and pulse delay. After an initial dip, the fluorescence was found to increase monotonically with pulse delay, reaching a plateau after some tens of picoseconds, depending on the material and fluence. The enhancement ratio (defined as the ratio of the fluorescence produced by the pulse pair to that produced by a single pulse of the same total fluence) reaches a maximum value of 6 and 11 at a fluence of {approx}6 J/cm{sup 2} for Si and Cu, respectively, and declines to a value below 2 at higher fluences. In contrast, the enhancement for CaF{sub 2} increases slowly from zero near threshold to a broad maximum value of 2 near 50 J/cm{sup 2}. Using reflectivity and atomic force microscopy measurements as diagnostics, we interpret the Si and Cu behavior in terms of a two phase mechanism, in which the first pulse melts the surface of the crystal and the second pulse ablates the resulting liquid film. A qualitatively different mechanism initiated by multiphoton absorption is involved in CaF{sub 2} ablation.

  11. Laser Produced Plasma Takle Atomic and Nuclear Processes

    NASA Astrophysics Data System (ADS)

    Belyaev, Vadim

    2000-03-01

    It is demonstrated that the transformation of superstrong fields in a laser-produced plasma by atomic structures leads to the generation of magnetic fields in an atom, which destroy the internal structure of low-lying electronic shells and give rise to the wave collapse, or nucleation, of the fields with subsequent strong action on nuclei. The mechanism behind the direct transfer (inner conversion) of energy of excited nuclei due to electrons is analyzed. Electromagnetic stimulation of artificial radioactivity in a laser-produced plasma is considered. The developed theory makes it possible to account for the mechanism of nuclear fusion of elements with light-weight nuclei in a laser-produced plasma. The first results of experiments on electromagnetic stimulation of atomic and nuclear processes in a laser-produced plasma excited under the action of terawatt laser radiation on a target are presented. The present work was supported by International Science and Technology Center under Project number 856.

  12. Nanosized lithium titanates produced by plasma technique

    NASA Astrophysics Data System (ADS)

    Grabis, J.; Orlovs, A.; Rasmane, Dz

    2007-12-01

    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 Li2TiO3 and Li4Ti5O12 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 °C improves phase composition of lithium titanates.

  13. Reinjection of transmitted laser light into laser-produced plasma for efficient laser ignition.

    PubMed

    Endo, Takuma; Takenaka, Yuhei; Sako, Yoshiyuki; Honda, Tomohisa; Johzaki, Tomoyuki; Namba, Shinichi

    2016-02-10

    For improving the laser absorption efficiency in laser ignition, the transmitted laser light was returned to the laser-produced plasma by using a corner cube. In the experiments, the transmitted light was reinjected into the plasma at different times. The laser absorption efficiency was found to be substantially improved when the transmitted light was reinjected into the plasma after adequate plasma expansion. Furthermore, through visualization experiments on gas-dynamics phenomena, it was found that the reinjection of the transmitted light affected not only the laser absorption efficiency but also the gas dynamics after breakdown, and thereby the initial flame kernel development. PMID:26906388

  14. Initiation of vacuum insulator surface high-voltage flashover with electrons produced by laser illumination

    NASA Astrophysics Data System (ADS)

    Krasik, Ya. E.; Leopold, J. G.

    2015-08-01

    In this paper, experiments are described in which cylindrical vacuum insulator samples and samples inclined at 45° relative to the cathode were stressed by microsecond timescale high-voltage pulses and illuminated by focused UV laser beam pulses. In these experiments, we were able to distinguish between flashover initiated by the laser producing only photo-electrons and when plasma is formed. It was shown that flashover is predominantly initiated near the cathode triple junction. Even dense plasma formed near the anode triple junction does not necessarily lead to vacuum surface flashover. The experimental results directly confirm our conjecture that insulator surface breakdown can be avoided by preventing its initiation [J. G. Leopold et al., Phys. Rev. ST Accel. Beams 10, 060401 (2007)] and complement our previous experimental results [J. Z. Gleizer et al., IEEE Trans. Dielectr. Electr. Insul. 21, 2394 (2014) and J. Z. Gleizer et al., J. Appl. Phys. 117, 073301 (2015)].

  15. Initial Cassini Plasma Observations at Saturn

    NASA Astrophysics Data System (ADS)

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

    2004-11-01

    The Cassini Plasma Spectrometer (CAPS) measures ion energy and mass composition from 1 eV to 50 keV and electron energy from 1 eV to 28 keV. It thus fills in important gaps in earlier Voyager measurements of energy and, in particular, ion composition. We give an overview of data taken during the first two Cassini orbits, including an overflight of the rings with closest approach of 1.33 Saturn radii and a close flyby of Titan at 1250 km. Several distinct and dynamic plasma regions have been identified, in particular a co-rotating plasmasphere dominated by water group ions between 2.2 14 Saturn radii, and a cold ionosphere of oxygen ions over the rings.

  16. Optical diagnostics of laser-produced plasmas at UCLA

    SciTech Connect

    Clayton, C.E.

    1985-05-01

    This paper reviews some of the optical diagnostics employed in probing laser-produced plasmas, in conjunction with laser-plasma interaction experiments at UCLA. Experimental apparatus, techniques, and some results will be presented for the following diagnostics: (1) collective Thomson scattering, for analyzing the space and time dependence of nonthermal (driven) waves in plasmas. Here, cylindrical focusing allows us to illuminate and thus image an interaction region of approximately 1 cm in length. This 1D image is then time resolved using either a streak camera or image dissection techniques; (2) dark-field photography, for quantitatively probing small-scale plasmas or for probing small-scale perturbations within larger plasmas. Here, the plasma produces a phase perturbation on the probing beam's wave front. Measurement of the exposure level on the recording film gives a measurement of the magnitude of the phase perturbation (squared) and thus of the line integrated plasma density; and (3) CO/sub 2/ wavelength interferometry, for obtaining useful interferograms of plasmas of small density-length products.

  17. Kinetic-energy structure of a laser-produced-plasma channel in air

    NASA Astrophysics Data System (ADS)

    Shu, Xiao-Fang; Yu, Cheng-Xin; Li, Wei; Liu, Shi-Bing

    2015-12-01

    In this paper, we propose a method to calculate the fine structure of kinetic energy of laser-produced plasma, which bridges the two parts of researches of plasma channel usually studied independently of each other, i.e., the extension of the length of plasma filament and the prolongation of the lifetime of plasma channel generated by the laser pulse. The kinetic energy structure of the plasma channel is calculated by solving the motion equation of ionized electrons and utilizing the ionization rate as the weighting factor. With the study on the laser intensity, we analyze the formation mechanisms of the kinetic energy structure. This work holds great promise for optimizing the initial conditions of the evolutions of plasma channel after the laser pulse.

  18. Focused Laser Initiated, RF Sustained, High Pressure Air Plasmas

    NASA Astrophysics Data System (ADS)

    Li, Yan; Scharer, John

    2013-10-01

    Measurements and analysis of air breakdown processes and plasma production were carried out by focusing 193 nm, 300 mJ, 15 MW high power laser radiation inside a Pyrex chamber surrounded by a 6 cm diameter helical RF coil. We observe quantum resonant multi-photon (REMPI) and collisional cascade laser ionization processes that produce high density (ne ~ 5*1015/cm3) cylindrical seed plasmas. The focused laser and associated shock wave produces a plasma seed for sustainment by the RF (1-10 kW, 0.5-1.8 s) pulse. The laser seed plasma increases the air RF breakdown pressure from 60 torr to 85 torr with 5 kW incident RF power and in lower pressure conditions the laser decreases the time between firing the RF pulse and formation of plasma. We also observed that the two capacitor settings in the matching system are important in determining the breakdown pressure and plasma parameters. To diagnose the inductive (~ 1012/cc) and capacitive (~ 1011/cc) plasmas with different properties, we use our 105 GHz (mm wave) interferometer to measure plasma density, collision frequency and electron temperature. Spectroscopic measurements of the plasma and comparison with the SPECAIR code are made to determine rotational, vibrational and neutral gas temperatures. A directional coupler in the RF system is applied to obtain the incident and reflection RF signals, with which we can calculate both magnitude and phase of the reflection coefficient and determine via FFT methods the time dependent plasma impedance.

  19. Collisional coupling in counterstreaming laser-produced plasmas

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

  20. Radiative heat transport instability in a laser produced inhomogeneous plasma

    NASA Astrophysics Data System (ADS)

    Bychenkov, V. Yu.; Rozmus, W.

    2015-08-01

    A laser produced high-Z plasma in which an energy balance is achieved due to radiation emission and radiative heat transfer supports ion acoustic instability. A linear dispersion relation is derived, and instability is compared to the radiation cooling instability [R. G. Evans, Plasma Phys. Controlled Fusion 27, 751 (1985)]. Under conditions of indirect drive fusion experiments, the driving term for the instability is the radiative heat flux and, in particular, the density dependence of the radiative heat conductivity. A specific example of thermal Bremsstrahlung radiation source has been considered. This instability may lead to plasma jet formation and anisotropic x-ray generation, thus affecting inertial confinement fusion related experiments.

  1. The physics and applications of nanomaterials produced with nonthermal plasmas

    NASA Astrophysics Data System (ADS)

    Kortshagen, Uwe

    2011-10-01

    Nonthermal plasmas provide an intriguing environment for the synthesis of nanomaterials. Not only does the unipolar negative charging of nanoparticles in plasmas yield significantly more monodisperse particle size distributions than other gas phase processes; the selective heating of small particulates in plasmas also enables producing high quality nanocrystals of high melting point materials. Nonthermal plasma hence proof to be ideal media for the synthesis of nanocrystals of covalently bonded semiconductors of the group IV and group III-V materials systems. This talk will discuss the unique physical principles of nanoparticle synthesis in plasmas. The presentation will also give examples of the applications of such plasma-produced nanomaterials to photovoltaic and light-emitting devices. The presenter hopes to make the case that nonthermal plasmas can fill a unique niche in the synthesis of nanomaterials that may proof of significant nonthermal value for applications in materials engineering, printed electronics, and renewable energy technology. The material presented in this presentation is an overview over results that were obtained under different grants funded by the National Science Foundation, including MRSEC grant DMR-0819885, EECS-0925624, CBET-0756326, and CBET-0500332.

  2. Ramp-up of CHI Initiated Plasmas on NSTX

    SciTech Connect

    Mueller, D; Bell, R E; LeBlanc, B; Roquemore, A L; Raman, R; Jarboe, T R; Nelson, B A

    2009-10-29

    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.

  3. Studies of Magnetic Reconnection in Colliding Laser-Produced Plasmas

    NASA Astrophysics Data System (ADS)

    Rosenberg, Michael

    2013-10-01

    Novel images of magnetic fields and measurements of electron and ion temperatures have been obtained in the magnetic reconnection region of high- β, laser-produced plasmas. Experiments using laser-irradiated foils produce expanding, hemispherical plasma plumes carrying MG Biermann-battery magnetic fields, which can be driven to interact and reconnect. Thomson-scattering measurements of electron and ion temperatures in the interaction region of two colliding, magnetized plasmas show no thermal enhancement due to reconnection, as expected for β ~ 8 plasmas. Two different proton radiography techniques used to image the magnetic field structures show deformation, pileup, and annihilation of magnetic flux. High-resolution images reveal unambiguously reconnection-induced jets emerging from the interaction region and show instabilities in the expanding plasma plumes and supersonic, hydrodynamic jets due to the plasma collision. Quantitative magnetic flux data show that reconnection in experiments with asymmetry in the scale size, density, temperature, and plasma flow across the reconnection region occurs less efficiently than in similar, symmetric experiments. This result is attributed to disruption of the Hall mechanism mediating collisionless reconnection. The collision of plasmas carrying parallel magnetic fields has also been probed, illustrating the deformation of magnetic field structures in high-energy-density plasmas in the absence of reconnection. These experiments are particularly relevant to high- β reconnection environments, such as the magnetopause. This work was performed in collaboration with C. Li, F. Séguin, A. Zylstra, H. Rinderknecht, H. Sio, J. Frenje, and R. Petrasso (MIT), I. Igumenshchev, V. Glebov, C. Stoeckl, and D. Froula (LLE), J. Ross and R. Town (LLNL), W. Fox (UNH), and A. Nikroo (GA), and was supported in part by the NLUF, FSC/UR, U.S. DOE, LLNL, and LLE.

  4. Plasma puff initiation of high Coulomb transfer switches

    NASA Technical Reports Server (NTRS)

    Venable, D. D.; Choi, E. H.

    1990-01-01

    The plasma-puff triggering mechanism based on a hypocycloidal pinch geometry was investigated to determine the optimal operating conditions for the azimuthally uniform surface flashover which initiates plasma-puff under wide range of fill gas pressure of Ar, He and N2. The optimal fill gas pressure for the azimuthally uniform plasma-puff was about 120 mTorr and 450 Torr for He and N2, and between 120 mTorr and 5 Torr for Ar. The inverse pinch switch was triggered with the plasma-puff and the switching capability under various electrical parameters and working gas pressures of Ar, He and N2 was determined. It was also shown that the azimuthally uniform switching discharges were dependent on the type of fill gas and its fill pressure. A new concept of plasma-focus driven plasma-puff was also discussed in comparison with the hypocycloidal pinch plasma-puff triggering. The main discharge of inverse pinch switch with plasma-focus driven plasma-puff trigger is found to be more azimuthally uniform than that with hypocycloidal pinch plasma-puff trigger in a gas pressure region between 80 mTorr and 1 Torr.

  5. Emission from weakly nonideal helium plasmas produced in flash lamps

    NASA Astrophysics Data System (ADS)

    Vitel, Y.; El Bezzari, M.; D'yachkov, L. G.; Kurilenkov, Yu. K.

    1998-12-01

    High pressure pulsed arcs produced in flash lamps filled with pure helium are applied for the generation of weakly nonideal plasmas characterized by a temperature T~2 eV and a coupling parameter ?~0.1 (ratio of the mean electrostatic interaction energy of two charge carriers to their mean kinetic energy). Radiative emission from flash lamps in the spectral range 300-850 nm is measured and calculated, taking into account the nonideal effects (through plasma quasistatic microfields) and the inhomogeneity of the arc plasma. Radial profiles of temperature and particle densities are deduced from the measurements of neutral line intensities and transverse distributions of emission. Temperature and electron density values are also obtained from absorption and laser interferometric measurements, respectively. Calculated and measured plasma spectra obtained are in good agreement at electron densities ~1018 cm-3.

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

    SciTech Connect

    Roy, Amitava; Harilal, Sivanandan S.; Hassan, Syed M.; Endo, Akira; Mocek, Tomas; Hassanein, A.

    2015-06-01

    We investigated the expansion dynamics of laser-produced plasmas expanding into an axial magnetic field. Plasmas were generated by focusing 1.064 µm Nd:YAG laser pulses onto a planar tin target in vacuum and allowed to expand into a 0.5 T magnetic-filed where field lines were aligned along the plume expansion direction. Gated images employing intensified CCD showed focusing of the plasma plume, which were also compared with results obtained using particle-in-cell modelling methods. The estimated density and temperature of the plasma plumes employing emission spectroscopy revealed significant changes in the presence and absence of the 0.5T magnetic field. In the presence of the field, the electron temperature is increased with distance from the target, while the density showed opposite effects.

  7. Interaction of plasma clouds produced from two laser targets

    SciTech Connect

    Annenkov, V. I.; Bessarab, A. V.; Bondarenko, G. A.; Dolgoleva, G. V.; Zhmailo, V. A.; Krotov, V. A.; Kovalenko, V. P.; Kunin, A. V.; Nikitin, I. N.; Novikiova, E. A.; Panov, A. I.; Sobolev, I. V.; Sokolov, S. S.; Starodubtsev, V. A.; Sungatullin, R. R.; Shirokov, A. E.

    2007-05-15

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

  8. Electrostatic structure of a magnetized laser-produced plasma

    NASA Astrophysics Data System (ADS)

    Bonde, Jeffrey; Vincena, Stephen; Gekelman, Walter

    2015-11-01

    Measurements of the structure of the electrostatic fields produced by the expansion of a laser-produced plasma into a background magnetized plasma are presented. The three-dimensional measurements of the electrostatic field are made using an emissive probe that measures the time-varying plasma potential on two orthogonal planes, one across and one containing the background magnetic field. The inductive electric field is also calculated from probe measurements of the time-varying magnetic fields. Deviations from local charge neutrality at the level of 10-4 generate a radial electrostatic field with peak strength an order of magnitude larger than the corresponding inductive field. The electrostatic energy density near full expansion is over an order of magnitude larger than that of the induced azimuthal electric field. These measurements show that electrostatic fields must be included in theoretical and computational models of collisionless coupling in magnetized point explosions of laser-produced plasmas and their relation to similar phenomena such as magnetospheric chemical releases.

  9. Optical diagnostics of line-focused laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Lin, Li-Huang; Chen, Shisheng; Jiang, Z. M.; Ge, Wen; Qian, Aidi; Bin, Ouyang; Li, Yongchun; Kang, Yilan; Xu, Zhizhan

    1991-01-01

    To find out homogeneous line-shaped plasma as a gain mediuni of soft Xray lasers produced by linefocused lasers the hydrodynamic characteristics and forms of harmonic and X-ray emission profiles of the plasma colunu-is have been studied with optical diagnostic equipments such as the five-frame laser probing diagnostic system the micrographic diagnostic systems and the spectral resolved Xray pinhole camera. Some experimental results are given and the emphasis is put on those of the halfcylindricalgroove shell targets. The results show that the halfcylindrical groove shell target may be favorable for soft X-ray laser research. 1 .

  10. Electron energy distribution produced by beam-plasma discharge

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  11. Morphology of ceramic particles produced by plasma-chemical synthesis

    NASA Astrophysics Data System (ADS)

    Arkhipov, V. A.; Bondarchuk, S. S.; Gol'din, V. D.; Zharova, I. K.; Zhukov, A. S.

    2015-11-01

    Thermal and diffusion processes in the droplet weakly concentrated metal salt solution during its heating in the plasma chemical reactor, in order to synthesize metal oxide powders are considered. Numerical study is based on previously proposed physical-mathematical model. The results of numerical calculations are analyzed to assess the possible influence of the operation parameters of the reactor and the characteristics of the initial solution (precursor) on the morphology of the particles formed.

  12. Plasma observations near Neptune: Initial results for Voyager 2

    SciTech Connect

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

    1989-12-15

    The plasma science experiment on Voyager 2 made observations of the plasma environment in Neptune's magnetosphere and in the surrounding solar wind. Because of the large tilt of the magnetic dipole and fortuitous timing, Voyager entered Neptune's magnetosphere through the cusp region, the first cusp observations at an outer planet. Thus the transition from the magnetosheath to the magnetosphere observed by Voyager 2 was not sharp but rather appeared as a gradual decrease in plasma density and temperature. The maximum plasma density observed in the magnetosphere is inferred to be 1.4 per cubic centimeter (the exact value depends on the composition), the smallest observed by Voyager in any magnetosphere. The plasma has at least two components; light ions (mass, 1 to 5) and heavy ions (mass, 10 to 40), but more precise species identification is not yet available. Most of the plasma is concentrated in a plasma sheet or plasma torus and near closest approach to the planet. A likely source of the heavy ions is Triton's atmosphere or ionosphere, whereas the light ions probably escape from Neptune. The large tilt of Neptune's magnetic dipole produces a dynamic magnetosphere that changes configuration every 16 hours as the planet rotates.

  13. Plasma observations near neptune: initial results from voyager 2.

    PubMed

    Belcher, J W; Bridge, H S; Bagenal, F; Coppi, B; Divers, O; Eviatar, A; Gordon, G S; Lazarus, A J; McNutt, R L; Ogilvie, K W; Richardson, J D; Siscoe, G L; Sittler, E C; Steinberg, J T; Sullivan, J D; Szabo, A; Villanueva, L; Vasyliunas, V M; Zhang, M

    1989-12-15

    The plasma science experiment on Voyager 2 made observations of the plasma environment in Neptune's magnetosphere and in the surrounding solar wind. Because of the large tilt of the magnetic dipole and fortuitous timing, Voyager entered Neptune's magnetosphere through the cusp region, the first cusp observations at an outer planet. Thus the transition from the magnetosheath to the magnetosphere observed by Voyager 2 was not sharp but rather appeared as a gradual decrease in plasma density and temperature. The maximum plasma density observed in the magnetosphere is inferred to be 1.4 per cubic centimeter (the exact value depends on the composition), the smallest observed by Voyager in any magnetosphere. The plasma has at least two components; light ions (mass, 1 to 5) and heavy ions (mass, 10 to 40), but more precise species identification is not yet available. Most of the plasma is concentrated in a plasma sheet or plasma torus and near closest approach to the planet. A likely source of the heavy ions is Triton's atmosphere or ionosphere, whereas the light ions probably escape from Neptune. The large tilt of Neptune's magnetic dipole produces a dynamic magnetosphere that changes configuration every 16 hours as the planet rotates. PMID:17756003

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

    NASA Technical Reports Server (NTRS)

    Belcher, J. W.; Bridge, H. S.; Coppi, B.; Gordon, G. S., Jr.; Lazarus, A. J.; Mcnutt, R. L., Jr.; Bagenal, F.; Divers, O.; Eviatar, A.; Ogilvie, K. W.

    1989-01-01

    The plasma science experiment on Voyager 2 made observations of the plasma environment in Neptune's magnetosphere and in the surrounding solar wind. Because of the large tilt of the magnetic dipole and fortuitous timing, Voyager entered Neptune's magnetosphere through the cusp region, the first cusp observations at an outer planet. Thus the transition from the magnetosheath to the magnetosphere observed by Voyager 2 was not sharp but rather appeared as a gradual decrease in plasma density and temperature. The maximum plasma density observed in the magnetosphere is inferred to be 1.4 per cubic centimeter (the exact value depends on the composition), the smallest observed by Voyager in any magnetosphere. The plasma has at least two components; light ions (mass, 1 to 5) and heavy ions (mass, 10 to 40), but more precise species identification is not yet available. Most of the plasma is concentrated in a plasma sheet or plasma torus and near closest approach to the planet. A likely source of the heavy ions is Triton's atmosphere or ionosphere, whereas the light ions probably escape from Neptune. The large tilt of Neptune's magnetic dipole produces a dynamic magnetosphere that changes configuration every 16 hours as the planet rotates.

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

    NASA Astrophysics Data System (ADS)

    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).

  16. Spectroscopic Analysis and Thomson Scattering Diagnostics of Wire Produced Plasma

    NASA Astrophysics Data System (ADS)

    Plechaty, Christopher; Sotnikov, Vladimir; Main, Daniel; Caplinger, James; Wallerstein, Austin; Kim, Tony

    2014-10-01

    The Lower Hybrid Drift Instability (LHDI) in plasma is driven by the presence of inhomogeneities in density, temperature, or magnetic field (Krall 1971, Davidson 1977), and occurs in systems where the electrons are magnetized and the ions are effectively unmagnetized. The LHDI is thought to occur in magnetic reconnection (Huba 1977), and has also been investigated as a mitigation technique which can allow for communications to take place through the plasma formed around hypersonic aircraft (Sotnikov 2010). To further understand the phenomenology of the LHDI, we plan to carry out experiments at the Air Force Research Laboratory, in the newly formed Plasma Physics Sensors Laboratory. In experiment, a pulsed power generator is employed to produce plasma by passing current through single, or dual-wire configurations. To characterize the plasma, a Thomson scattering diagnostic is employed, along with a visible spectroscopy diagnostic. This work was performed under the auspices of the U.S. Department of Defense by Riverside Research under Contract BAA-FA8650-13-C-1539.

  17. Plasma-puff initiation of high Coulomb transfer switches

    NASA Technical Reports Server (NTRS)

    Venable, D. D.; Han, K. S.

    1993-01-01

    The plasma-puff triggering mechanism based on a hypocycloidal pinch geometry was investigated to determine the optimal operating conditions for an azimuthally uniform surface flashover which initiates plasma-puff under wide ranges of fill gas pressures of Ar, He and N2. The optimal fill gas pressures for the azimuthally uniform plasma-puff were about 120 mTorr less than P(opt) less than 450 Torr for He and N2. For Argon 120 mTorr less than P(opt) less than 5 Torr for argon. The inverse pinch switch was triggered with the plasma-puff and the switching capability under various electrical parameters and working gas pressures of Ar, He and N2 was determined. It was also shown that the azimuthally uniform switching discharges were dependent on the type of fill gas and its fill pressure. A new concept of plasma-focus driven plasma-puff was also discussed in comparison with hypocycloidal pinch plasma-puff triggering. The main discharge of the inverse pinch switch with the plasma-focus driven plasma-puff trigger is found to be more azimuthally uniform than that with the hypocycloidal pinch plasma-puff trigger in a gas pressure region between 80 mTorr and 1 Torr. In order to assess the effects of plasma current density on material erosion of electrodes, emissions from both an inverse-pinch plasma switch (INPIStron) and from a spark gap switch under test were studied with an optical multichannel analyzer (OMA). The color temperature of the argon plasma was approximately 4,000 K which corresponded with the peak continuum emission near 750 nm. There are the strong line emissions of argon in the 650 - 800 nm range and a lack of line emissions of copper and other solid material used in the switch. This indicates that the plasma current density during closing is low and the hot spot or hot filament in the switch is negligible. This result also indicates considerable reduction of line emission with the INPIStron switch over that of a spark-gap switch. However, a strong carbon line emission exists due to vaporization of the plastic insulator used. In order to reduce the vaporization of the insulator, the plexiglass insulating material of INPIStron was replaced with Z-9 material. A comparative study of the INPIStron and a spark gap also reveals that the INPIStron, with a low impedance of Z equals 9 ohms, can transfer a high voltage pulse with a superior pulse-shape fidelity over that of a spark gap with Z equals 100 ohms.

  18. Plasma-puff initiation of high Coulomb transfer switches

    NASA Technical Reports Server (NTRS)

    Han, Kwang S.; Venable, Demetrius D.; Lee, Ja H.; Choi, Eun H.; Kim, Y. K.; Kim, J. H.; Nguyen, D. X.

    1993-01-01

    The plasma-puff triggering mechanism based on a hypocycloidal pinch geometry was investigated to determine the optimal operating conditions for an azimuthally uniform surface flashover which initiates plasma-puff under wide ranges of fill gas pressures of Ar, He and N2. The optimal fill gas pressures for the azimuthally uniform plasma-puff were about 120 mTorr less than P(sub opt) less than 450 Torr for He and N2. For Argon 20 mTorr is less than P(sub opt) is less than 5 Torr. The inverse pinch switch was triggered with the plasma-puff and the switching capability under various electrical parameters and working gas pressures of Ar, He and N2 was determined. It was also shown that the azimuthally uniform switching discharges were dependent on the type of fill gas and its fill pressure. A new concept of plasma-focus driven plasma-puff was also discussed in comparison with hypocycloidal pinch plasma-puff triggering. The main discharge of the inverse pinch switch with the plasma-focus driven plasma-puff trigger is found to be more azimuthally uniform than that with the hypocycloidal pinch plasma-puff trigger in a gas pressure region between 80 mTorr and 1 Torr. In order to assess the effects of plasma current density on material erosion of electrodes, emissions from both an inverse-pinch plasma switch (INPIStron) and from a spark gap switch under test were studied with an optical multichannel analyzer (OMA). The color temperature of the argon plasma was approximately 4,000 K which corresponded with the peak continuum emission near 750 nm. There are the strong line emissions of argon in the 650 - 800 nm range and a lack of line emissions of copper and other solid material used in the switch. This indicates that the plasma current density during closing is low and the hot spot or hot filament in the switch is negligible. This result also indicates considerable reduction of line emission with the INPIStron switch over that of a spark-gap switch. However, a strong carbon line emission exists due to vaporization of the plastic insulator used. In order to reduce the vaporization of the insulator, the plexiglass insulating material of INPIStron was replaced with Z-9 material. A comparative study of the INPIStron and a spark gap also reveals that the INPIStron, with a low impedance of Z = 9 ohms, can transfer a high voltage pulse with a superior pulse-shape fidelity over that of a spark gap with Z = 100 ohms.

  19. Energetics of oriented nuclei in laser-produced plasma

    NASA Astrophysics Data System (ADS)

    Belyaev, Vadim S.

    2004-06-01

    The report presents principal theoretical and experimental results obtained during the first year of the ISTC project # 2155 realization. The mechanisms of high-energy electrons formation in high intensity and short laser pulse interaction with solid targets has been suggested and investigated. Neutron generation (reaction D + D --> 3He + n) from laser-produced plasma at 1017 W/cm2 intensity has been investigated. Neutron yield more than 104 per pulse was received.

  20. Plasma polymerization of 2-chloro-p-xylene to produce a crystalline plasma parylene C film

    NASA Astrophysics Data System (ADS)

    Estrada-Raygoza, Isabel C.; Thamban, Stephan L.; Overzet, Lawrence; Goeckner, Matthew

    2013-09-01

    The following work reports the study of the plasma polymerization of 2-chloro-p-xylene monomer to produce a plasma polymer film like Parylene C, a biocompatible polymer widely used in the medical field. This is the first example of a plasma polymer that presents a degree of crystallinity. Our data suggests that the film growth/polymerization of plasma deposited Parylene C is affected by both the adsorption of the monomer in the surface and the generation of precursors for polymerization by the plasma. Film deposition occurred mostly in areas exposed to ion bombardment, thus polymerization of the films is likely to be enhanced by ions but we cannot discard some small radical contribution. We used Fourier transform infrared spectroscopy, optical emission spectroscopy (OES) and an electron beam OES diagnostic tools to study the dissociation, excitation and ionization fragments produced in the plasma discharge. The main products of the monomer breakup are HCl, CH4, C2H2, H, H2, Cl, Cl2, CH, HCl + and a mix of aromatic ions/radicals. By using a novel OES e-beam diagnostic we could track real time changes in the OES intensities of the excited species being produced and consumed in the plasma. This work was supported by CONACYT-UT Dallas scholarship 303255 and NSF Grant CBET- 0922962.

  1. Plasma irregularities in the D-region ionosphere in association with sprite streamer initiation

    NASA Astrophysics Data System (ADS)

    Qin, Jianqi; Pasko, Victor P.; McHarg, Matthew G.; Stenbaek-Nielsen, Hans C.

    2014-05-01

    Sprites are spectacular optical emissions in the mesosphere induced by transient lightning electric fields above thunderstorms. Although the streamer nature of sprites has been generally accepted, how these filamentary plasmas are initiated remains a subject of active research. Here we present observational and modelling results showing solid evidence of pre-existing plasma irregularities in association with streamer initiation in the D-region ionosphere. The video observations show that before streamer initiation, kilometre-scale spatial structures descend rapidly with the overall diffuse emissions of the sprite halo, but slow down and stop to form the stationary glow in the vicinity of the streamer onset, from where streamers suddenly emerge. The modelling results reproduce the sub-millisecond halo dynamics and demonstrate that the descending halo structures are optical manifestations of the pre-existing plasma irregularities, which might have been produced by thunderstorm or meteor effects on the D-region ionosphere.

  2. Plasma irregularities in the D-region ionosphere in association with sprite streamer initiation.

    PubMed

    Qin, Jianqi; Pasko, Victor P; McHarg, Matthew G; Stenbaek-Nielsen, Hans C

    2014-01-01

    Sprites are spectacular optical emissions in the mesosphere induced by transient lightning electric fields above thunderstorms. Although the streamer nature of sprites has been generally accepted, how these filamentary plasmas are initiated remains a subject of active research. Here we present observational and modelling results showing solid evidence of pre-existing plasma irregularities in association with streamer initiation in the D-region ionosphere. The video observations show that before streamer initiation, kilometre-scale spatial structures descend rapidly with the overall diffuse emissions of the sprite halo, but slow down and stop to form the stationary glow in the vicinity of the streamer onset, from where streamers suddenly emerge. The modelling results reproduce the sub-millisecond halo dynamics and demonstrate that the descending halo structures are optical manifestations of the pre-existing plasma irregularities, which might have been produced by thunderstorm or meteor effects on the D-region ionosphere. PMID:24806314

  3. Plasma observations near Saturn - Initial results from Voyager 2

    NASA Technical Reports Server (NTRS)

    Bridge, H. S.; Bagenal, F.; Belcher, J. W.; Lazarus, A. J.; Mcnutt, R. L.; Sullivan, J. D.; Gazis, P. R.; Hartle, R. E.; Ogilvie, K. W.; Scudder, J. D.

    1982-01-01

    Results of plasma measurements made by Voyager 2 in the vicinity of Saturn are discussed and compared with those made by Pioneer 11 and Voyager 1 in a more limited range of latitudes. The initial bow shock crossing on the inbound trajectory closely agreed with the shock position inferred from the external ram pressure in the solar wind, although boundaries on the outbound pass were much further out than expected. Magnetospheric plasma observations reveal the presence of (1) shocked solar wind plasma in the magnetosheath between 30 and 22 Saturn radii; (2) a variable density region between 17 Saturn radii and the magnetopause; (3) an extended thick plasma sheet between 17 and 7 Saturn radii; and (4) an inner plasma torus probably originating from local sources. The ratio of heavy to light ions was observed to vary with distance to the equatorial plane in the dayside magnetosphere, with the heavy ions, probably O(+), more closely confined to the equatorial plane. The plasma data also account for the observed inner boundary of the neutral hydrogen torus discovered by Voyager 1.

  4. Hydrolysis of hemicellulose to produce fermentable monosaccharides by plasma acid.

    PubMed

    Wang, Ying; Yuan, Bo; Ji, Yingchao; Li, Hong

    2013-09-12

    In this paper, plasma acid was obtained by treating distilled water with dielectric barrier discharge to hydrolyze hemicellulose. The orthogonal experiment L??(5(6)) was used to optimize such hydrolysis conditions. The total reducing sugar (TRS) was measured by the DNS method. To determine whether the oligosaccharide existed in the hydrolysis products, it was hydrolyzed by sulfuric acid for a second time following the same procedure as reported earlier. The monosaccharide compositions of the hydrolyzed sample were analyzed by high-performance liquid chromatography (HPLC) and Fourier transformed infrared spectroscopy (FTIR). The results showed that pH 2.81 of plasma acid, 100 C and 50 min were assigned as an optimal hydrolysis condition by plasma acid. Under this condition, the hemicellulose was hydrolyzed completely to produce monosaccharides including xylose, glucose, and galactose with the mole ratio being 17:3:1. The yields of xylose, glucose, and galactose were 38.67%, 9.28% and 3.09%, respectively. Compared with the hemicellulose hydrolysis results by sulfuric acid, it is concluded that plasma acid is an environmental-friendly and efficient method to explore and hydrolyze the hemicellulose existed in biomass. PMID:23911479

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

    SciTech Connect

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

    1989-09-25

    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 {omega}=1.1{times}10{sup 6} rad/s, density {ital n}{similar to}10{sup 15} cm{sup {minus}3}, and ion temperature {ital T}{sub {ital 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.

  6. Inactivation of Escherichia coli ATCC 11775 in fresh produce using atmospheric pressure cold plasma

    NASA Astrophysics Data System (ADS)

    Bermudez-Aguirre, Daniela; Wemlinger, Erik; Barbosa-Canovas, Gustavo; Pedrow, Patrick; Garcia-Perez, Manuel

    2011-10-01

    Food-borne outbreaks are associated with the presence of pathogenic bacteria in food products such as fresh produce. One of the target microorganisms is Escherichia coli which exhibits resistance to being inactivated with conventional disinfection methods for vegetables. Atmospheric pressure cold plasma (APCP) was tested to disinfect three vegetables with challenge surfaces, lettuce, carrots and tomatoes. The produce was inoculated with the bacteria to reach an initial microbial concentration of 107 cfu/g. Vegetables were initially exposed to the APCP discharges from a needle array at 5.7 kV RMS in argon, processing times of 0.5, 3 and 5 min. Initial results indicate that microbial decontamination is effective on the lettuce (1.2 log reduction) when compared with other vegetables. To claim disinfection, a 3 log reduction or more is needed, which makes APCP treatment very promising technology for decontamination of produce. We propose that with method refinements full disinfection can be achieved using APCP.

  7. Acceleration of neutrals in a nanosecond laser produced nickel plasma

    SciTech Connect

    Smijesh, N.; Chandrasekharan, K.; Philip, Reji

    2014-12-15

    Time of flight dynamics of slow neutrals, fast neutrals, and ions from a nanosecond laser produced nickel (Ni) plasma are investigated. Species arrival times confirm the hypothesis that fast neutrals are formed by the recombination of fast ions with free electrons. Both neutrals and ions are found to accelerate for a short interval immediately after ablation, which is attributed to internal Coulomb forces which create electrostatic potentials resulting in the charged particle acceleration. This process is further enhanced by laser-plasma energy coupling. Emission from neutrals could be measured for longer axial distances in the plume compared to that of ions confirming that the ions recombine to form neutrals as they move away from the target surface.

  8. Acceleration of neutrals in a nanosecond laser produced nickel plasma

    NASA Astrophysics Data System (ADS)

    Smijesh, N.; Chandrasekharan, K.; Philip, Reji

    2014-12-01

    Time of flight dynamics of slow neutrals, fast neutrals, and ions from a nanosecond laser produced nickel (Ni) plasma are investigated. Species arrival times confirm the hypothesis that fast neutrals are formed by the recombination of fast ions with free electrons. Both neutrals and ions are found to accelerate for a short interval immediately after ablation, which is attributed to internal Coulomb forces which create electrostatic potentials resulting in the charged particle acceleration. This process is further enhanced by laser-plasma energy coupling. Emission from neutrals could be measured for longer axial distances in the plume compared to that of ions confirming that the ions recombine to form neutrals as they move away from the target surface.

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Relative ion expansion velocity in laser-produced plasmas

    SciTech Connect

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

    1988-07-15

    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/sup 14/ W/cm,/sup 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/sup 7/ cm/s in the expansion velocities of TiXIX and TiXX ions compared to TiXIII ions.

  11. Relative ion expansion velocity in laser-produced plasmas

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    The spectra of highly ionized titanium, Ti XIII through Ti XXI, and C VI 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 to the 14th W/sq cm, laser pulses at a wavelength of 351 nm. The measured wavelength for the 2p-3s Ti XIII resonance lines had an average shift of + 0.023 A relative to the C VI and Ti XX spectral lines. No shift was found between the C VI, Ti XIX, and Ti XX lines. The shift is attributed to a Doppler effect, resulting from a difference of (2.6 + or - 0.2) x 10 to the 7th cm/s in the expansion velocities of Ti XIX and Ti XX ions compared to Ti XIII ions.

  12. Experimental study of charge state distribution from KrF and ruby laser-produced plasmas

    SciTech Connect

    Tsui, Y.Y.; Fedosejevs, R.; Offenberger, A.A. )

    1993-09-01

    The detailed angular charge distributions of the asymptotic plasma produced from carbon and aluminum targets by UV and visible laser pulses in the intensity range of 10[sup 11]--10[sup 13] W cm[sup [minus]2] and pulselength range of 1--20 nsec have been measured using a single shot electrodynamic charge analyzer. The observed variation of average charge state as a function of velocity was determined from measurement and has been found to be approximately linear with no apparent dependence on angle of observation. For similar irradiation conditions, shorter-wavelength radiation produces lower final charge states, as expected, from the higher interaction density in the initial laser produced plasma leading to enhanced recombination in the early stages of expansion of the plasma. The characteristics of the angular charge distribution can be qualitatively explained by considering the flow of the source plasma mapping different regions of the focal spot into different angles, relative to the target normal, in the expanding plasma.

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  14. Fast Magnetic Reconnection in Laser-Produced Plasma Bubbles

    SciTech Connect

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

    2011-05-27

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

  15. Innovative X-? ray sources based on laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Curcio, A.; Giulietti, D.

    2015-07-01

    The paper concerns with the dynamics and the emitted radiation of electrons undergoing betatron oscillations in laser-produced plasmas. The topic is relevant for a reliable interpretation of data will be obtained in forthcoming experiments in the LASER facility of the National Laboratories of Frascati (LNF) of the National Institute for Nuclear Physics (INFN). The blowout regime will be considered, which makes the electrons reaching very high energies by providing impressive accelerating gradients while keeping a low energy spread value. The accident that the betatron emission occurs meanwhile electrons gain energy is also considered here.

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  17. Initiation and assembly of the plasma in a plasma flow switch

    SciTech Connect

    Bowers, R.L.; Greene, A.E.; Peterson, D.L.; Bartsch, R.R.; Cochrane, J.C.; Kruse, H.; Roderick, N.F.

    1996-04-01

    A series of fast opening switch experiments was carried out on the Pegasus pulsed power facility. The first series of experiments characterized the assembly and run down of a 50 mg plasma flow switch operating in the 6 MA regime. The switch plasma arises from the vaporization of a wire array and a barrier foil. Arrays with different numbers of wires were examined. Two-dimensional (2-D) radiation magnetohydrodynamic simulations of the initial vaporization stage of the array plasma and its assembly on the barrier foil are presented, which include the effects of initial perturbations on the evolution of the switch plasma as it moves down a coaxial gun barrel. Sparse wire arrays were observed to perform poorly. A change in the experimental design, motivated by 2-D simulations, led to improved performance. Computational results which lead to these changes are discussed, and the results are compared with experimental data.

  18. Saturation of Langmuir waves in laser-produced plasmas

    SciTech Connect

    Baker, K.L.

    1996-04-01

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

  19. A laser-plasma accelerator producing monoenergetic electron beams.

    PubMed

    Faure, J; Glinec, Y; Pukhov, A; Kiselev, S; Gordienko, S; Lefebvre, E; Rousseau, J-P; Burgy, F; Malka, V

    2004-09-30

    Particle accelerators are used in a wide variety of fields, ranging from medicine and biology to high-energy physics. The accelerating fields in conventional accelerators are limited to a few tens of MeV m(-1), owing to material breakdown at the walls of the structure. Thus, the production of energetic particle beams currently requires large-scale accelerators and expensive infrastructures. Laser-plasma accelerators have been proposed as a next generation of compact accelerators because of the huge electric fields they can sustain (>100 GeV m(-1)). However, it has been difficult to use them efficiently for applications because they have produced poor-quality particle beams with large energy spreads, owing to a randomization of electrons in phase space. Here we demonstrate that this randomization can be suppressed and that the quality of the electron beams can be dramatically enhanced. Within a length of 3 mm, the laser drives a plasma bubble that traps and accelerates plasma electrons. The resulting electron beam is extremely collimated and quasi-monoenergetic, with a high charge of 0.5 nC at 170 MeV. PMID:15457253

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

    SciTech Connect

    Terauchi, Hiromitsu; Bobrova, Nadezhda; Sasorov, Pavel; Kikuchi, Takashi; Sasaki, Toru; Higashiguchi, Takeshi; Yugami, Noboru; Kodama, Ryosuke

    2011-03-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

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

    PubMed

    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. PMID:23948051

  3. Strongly Polarized Plasma Emission Produced by Laser Ablation of Aluminum

    NASA Astrophysics Data System (ADS)

    Gordon, Robert; Liu, Yaoming; Penczak, John; Zhao, Youbo

    2009-05-01

    We have found that continuum emission produced in the laser ablation of a material may be strongly polarized, whereas as discrete atomic or ionic emission lines appear as minima in the plasma polarization spectrum [1]. This effect is indicative of strong directionality of electrons recombining in the plasma. By placing a polarizer before the detector, it is possible to suppress the continuum background, thereby greatly increasing the resolution and detection sensitivity. Previously this technique used double pulses of femtosecond Ti:Sapphire radiation to achieve maximum polarization [2]. Here we show that single pulses on both the fs and ns time scales produce strongly polarized spectra of Al. The effects of laser intensity, focal position, angle of incidence, and polarization state of the laser are explored. [4pt] [1] Y. Liu, S. Singha, T. E. Witt, and R. J. Gordon, Appl. Phys. Lett. 93, 161502 (2008).[0pt] [2] Y. Zhao, S. Singha, Y. Liu, and R. J. Gordon, Opt. Lett. 34 (in press).

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

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

    SciTech Connect

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

    2012-05-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

  7. Numerical study on the Z pinch dynamics of gas jet type discharge produced plasma (DPP) source

    NASA Astrophysics Data System (ADS)

    Huang, Bin; Xie, Bin; Tomizuka, Taku; Watanabe, Masato; Xiao, Feng; Hotta, Eiki

    2012-10-01

    Z pinch DPP source is often used as an Extreme Ultra-Violet (EUV) source. It is convenient to produce high temperature and high density plasma. There are several analytical models to describe the dynamics of the plasma. The snowplow model is a simple and widely used model to analyze the motion of the plasma shell and predict the pinch time; however, it is incapable of analyzing the plasma behavior after the maximum pinch and providing detailed information of concerned plasma parameters, such as electron density and electron temperature. In this study, we present the simulation results of the Z pinch DPP dynamics obtained by a 2D MHD code. This code solves the problem based on the assumption of single fluid, two temperature approximations in the cylindrical geometry. The numerical scheme for this MHD code is Total-Variation-Diminishing scheme in Lax Friedrich formulation (TVD-LF). The evolution of electron density, electron temperature, current density, magnetic flux and some other important parameters in Z pinch dynamics are investigated with this code. The simulation results show that the maximum pinch electron density is on the order of 10^19 cm-3, with a pinch plasma radius of about 0.1 mm. In order to optimize the radiation output, the influences of initial gas distribution and the current waveform on the Z pinch dynamics are also investigated. They affect the electron density at pinch stagnation obviously; while in term of electron temperature, the effect is slight.

  8. Stability of Human Thrombin Produced From 11 ml of Plasma Using the Thrombin Processing Device

    PubMed Central

    Kumar, Vijay; Madsen, Trista; Zhu, Haihong; Semple, Elisabeth

    2005-01-01

    Abstract: Autologous thrombin can be produced by activating the patients own plasma. By adding calcium chloride (CaCl2) to the anticoagulated plasma, the coagulation cascade will be initiated, and active thrombin will be produced. However, thrombin obtained by this method degrades very quickly and is not practical for use during surgery. The aim of this study was to investigate the stability of the thrombin produced using the thrombin processing device (TPD; Thermogenesis Corporation). The TPD consists of a tubular chamber containing a negatively charged surface for activation. Plasma (11 ml) and reagent (CaCl2 and ethanol, 3.75 ml) were added to the TPD, and active thrombin was harvested after a 20-minute incubation. The production of thrombin was done at 18C (64F), 24C (75F), and 27C (81F) (n = 4/group). The produced thrombin was stored at the production temperature, 4C (39F), and 35C (95F). The thrombin activity was assessed by time to clot formation, using a fibrinogen concentrate as substrate, after 2, 4, and 6 hours of storage. Thrombin produced at 18C had clot times of less than 5 seconds for 2 hours (4.42 1.3 seconds) when stored at 4C, but 4 hours (4.1 1.3 seconds) when stored at 35C. In contrast, when thrombin was produced at 24C, the clot times were 4.3 0.7 and 4.6 1.6 seconds at 4C and 35C, respectively, for up to 6 hours. Similar results were obtained for thrombin produced at 27C. Active thrombin produced by the TPD is dependent on both the production temperature and the storage temperature. Autologous human thrombin with a stability of up to 6 hours can be obtained using the TPD when produced at 24C or 27C and stored at 4C. PMID:16524159

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

    SciTech Connect

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

    2013-09-15

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

  10. Plasma processes for producing silanes and derivatives thereof

    SciTech Connect

    Laine, Richard M; Massey, Dean Richard; Peterson, Peter Young

    2014-03-25

    The invention is generally related to process for generating one or more molecules having the formula Si.sub.xH.sub.y, Si.sub.xD.sub.y, Si.sub.xH.sub.yD.sub.z, and mixtures thereof, where x,y and z are integers .gtoreq.1, H is hydrogen and D is deuterium, such as silane, comprising the steps of: providing a silicon containing material, wherein the silicon containing material includes at least 20 weight percent silicon atoms based on the total weight of the silicon containing material; generating a plasma capable of vaporizing a silicon atom, sputtering a silicon atom, or both using a plasma generating device; and contacting the plasma to the silicon containing material in a chamber having an atmosphere that includes at least about 0.5 mole percent hydrogen atoms and/or deuterium atoms based on the total moles of atoms in the atmosphere; so that a molecule having the formula Si.sub.xH.sub.y; (e.g., silane) is generated. The process preferably includes a step of removing one or more impurities from the Si.sub.xH.sub.y (e.g., the silane) to form a clean Si.sub.xH.sub.y, Si.sub.xD.sub.y, Si.sub.xH.sub.yD.sub.z (e.g., silane). The process may also include a step of reacting the Si.sub.xH.sub.y, Si.sub.xD.sub.y, Si.sub.xH.sub.yD.sub.z (e.g., the silane) to produce a high purity silicon containing material such as electronic grade metallic silicon, photovoltaic grade metallic silicon, or both.

  11. Initiation of nuclear reactions in femtosecond laser plasma

    SciTech Connect

    Golovinski, P. A.; Mikhin, E. A.

    2013-01-15

    Mechanisms of electron interaction with a nucleus via a direct electron-nucleus collision and via bremsstrahlung generated in electron scattering on a nucleus in a femtosecond laser plasma are considered. The description of this interaction is simplified substantially by using the instantaneous-impact and equivalent-photon approximations. The yields of photons, electron-positron pairs, and products of nuclear reactions initiated by a laser pulse for some nuclei are calculated. In particular, this is done for {sup 235}U, {sup 236}U, {sup 238}U, and {sup 232}Th fission in a laser field of intensity 10{sup 20} to 10{sup 22} W/cm{sup 2}.

  12. [Testing of medicinal products produced from pooled plasma].

    PubMed

    Unkelbach, U; Hunfeld, A; Breitner-Ruddock, S

    2014-10-01

    Medicinal products produced from human plasma fall under the administrative batch release procedure of the competent authority. In Germany, this has been carried out since 1995 by the Paul Ehrlich Institute (PEI), the responsible state control agency for blood products. Medicinal products released for the European and national market are tested for quality, efficacy and safety. Experimental testing of the final product and the starting materials, the plasma pools, as well as control of the production documentation guarantee a constantly high product safety. In the 28,000 batches tested since the beginning of the state controlled batch release testing of these blood products at the PEI, there has been no transmission of infectious viruses (HIV, HBV and HCV) to any patient. The batch release has made a contribution to the improvement of product quality. This procedure is still an important tool to ensure safety of blood products. The PEI is integrated in the batch release network of the European Directorate for the Quality of Medicines & Health Care (EDQM) in Strasbourg. Regulations and guidelines for official control authority batch release (OCABR) ensure harmonized procedures for mutual recognition of batch release on the European level. The EU certificates and German national certificates are requested and accepted in over 70 countries worldwide. Experimental testing in the EU and the requisite certificates have developed into a seal of quality for the world market. PMID:25213735

  13. Plasma Characteristics of the Discharge Produced during Mechanoluminescence

    SciTech Connect

    Eddingsaas, Nathan C.; Suslick, Kenneth S.

    2007-12-07

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

  14. Atmospheric plasma inactivation of foodborne pathogens on fresh produce surfaces.

    PubMed

    Critzer, Faith J; Kelly-Wintenberg, Kimberly; South, Suzanne L; Golden, David A

    2007-10-01

    A study was conducted to determine the effect of one atmosphere uniform glow discharge plasma (OAUGDP) on inactivation of Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes on apples, cantaloupe, and lettuce, respectively. A five-strain mixture of cultured test organisms was washed, suspended in phosphate buffer, and spot inoculated onto produce (7 log CFU per sample). Samples were exposed inside a chamber affixed to the OAUGDP blower unit operated at a power of 9 kV and frequency of 6 kHz. This configuration allows the sample to be placed outside of the plasma generation unit while allowing airflow to carry the antimicrobial active species, including ozone and nitric oxide, onto the food sample. Cantaloupe and lettuce samples were exposed for 1, 3, and 5 min, while apple samples were exposed for 30 s, 1 min, and 2 min. After exposure, samples were pummeled in 0.1% peptone water-2% Tween 80, diluted, and plated in duplicate onto selective media and tryptic soy agar and incubated as follows: E. coli O157:H7 (modified eosin methylene blue) and Salmonella (xylose lysine tergitol-4) for 48 h at 37 degrees C, and L. monocytogenes (modified Oxford medium) at 48 h for 32 degrees C. E. coli O157:H7 populations were reduced by >1 log after 30-s and 1-min exposures and >2 log after a 2-min exposure. Salmonella populations were reduced by >2 log after 1 min. Three- and 5-min exposure times resulted in >3-log reduction. L. monocytogenes populations were reduced by 1 log after 1 min of exposure. Three- and 5-min exposure times resulted in >3- and >5-log reductions, respectively. This process has the capability of serving as a novel, nonthermal processing technology to be used for reducing microbial populations on produce surfaces. PMID:17969610

  15. Plasma Parameter of a Capillary Discharge-Produced Plasma Channel to Guide an Ultrashort Laser Pulse

    SciTech Connect

    Higashiguchi, Takeshi; Terauchi, Hiromitsu; Bai, Jin-xiang; Yugami, Noboru

    2009-01-22

    We have observed the optical guiding of a 100-fs laser pulse with the laser intensity in the range of 10{sup 16} W/cm{sup 2} using a 1.5-cm long capillary discharge-produced plasma channel for compact electron acceleration applications. The optical pulse propagation using the plasma channel is achieved with the electron densities of 10{sup 17}-10{sup 18} cm{sup -3} and the electron temperatures of 0.5-4 eV at a discharge time delay of around 150 ns and a discharge current of 500 A with a pulse duration of 100-150 ns. An energy spectrum of the accelerated electrons from a laser-plasma acceleration scheme showed a peak at 1.3 MeV with a maximum energy tail of 1.6 MeV.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Enhancements of extreme ultraviolet emission using prepulsed Sn laser-produced plasmas for advanced lithography applications

    SciTech Connect

    Freeman, J. R.; Harilal, S. S.; Hassanein, A.

    2011-10-15

    Laser-produced plasmas (LPP) from Sn targets are seriously considered to be the light source for extreme ultraviolet (EUV) next generation lithography, and optimization of such a source will lead to improved efficiency and reduced cost of ownership of the entire lithography system. We investigated the role of reheating a prepulsed plasma and its effect on EUV conversion efficiency (CE). A 6 ns, 1.06 {mu}m Nd:yttrium aluminum garnet laser was used to generate the initial plasma that was then reheated by a 40 ns, 10.6 {mu}m CO{sub 2} laser to generate enhanced EUV emission from a planar Sn target. The effects of prepulsed laser intensity and delay timings between the prepulsed and the pumping pulse were investigated to find the optimal pre-plasma conditions before the pumping pulse. The initial optimization of these parameters resulted in 25% increase in CE from the tin LPP. The cause of increased EUV emission was identified from EUV emission spectra and ion signal data.

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

    PubMed

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

    2016-06-01

    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)). PMID:26583905

  19. Detailed energy distributions in laser-produced plasmas of solid gold and foam gold planar targets

    SciTech Connect

    Dong, Yunsong; Department of Engineering Physics, Tsinghua University, Beijing 100084 ; Zhang, Lu; Yang, Jiamin; Shang, Wanli

    2013-12-15

    Foam gold was proposed to increase the laser to x-ray conversion efficiency due to its important applications. To understand the mechanism of x-ray enhancement, the detailed energy distributions and plasma profiles for laser-irradiated solid gold and foam gold targets were studied comparatively by hydrodynamic simulations using the code Multi-1D. It is confirmed that the radiation heat wave is subsonic for the normal solid gold target, while supersonic for the foam gold target. The shock wave, which is behind the supersonic radiation heat wave for the foam gold target, generates a plasma temperature gradient with high temperature near the shock wave front to produce an additional net outward radiation for enhancement of the x-ray emission. Much larger inward plasma velocity is also driven by the shock wave as an initial plasma velocity for the laser deposition and electron thermal conduct zone, which decreases the expanding plasma kinetic energy loss and helps to increase the x-ray radiation.

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

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

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

  1. Focused excimer laser initiated and radio frequency sustained plasma formation in high pressure air

    NASA Astrophysics Data System (ADS)

    Giar, Ryan

    A doctoral thesis project was performed to experimentally investigate the feasibility of focused excimer laser initiation of air plasmas for radio frequency sustainment. A 193 nm, 15 MW, 300 mJ laser was focused with a 18 cm focal length lens to form a small, high density (ne ~ 10 14 cm--3) seed plasma. These laser plasmas were produced inside a borosilicate glass tube around which was wrapped a 5 turn helical antenna. This antenna was powered with 5 kW of 13.56 MHz of radiation for 1.5 s. This was accomplished at a pressure of 22 Torr, resulting in a large volume (300 cm3) air plasma. Diagnostic measurements of this air plasma determined an electron density of 5E10 cm-3 and an electron temperature 1.3 eV with a neutral temperature of 3500 K. The collision frequency was measured to be 9E10 Hz which resulted in a plasma-loaded antenna resistance of 6 O with a voltage reflection coefficient of 0.7.

  2. Focused excimer laser initiated, radio frequency sustained high pressure air plasmas

    NASA Astrophysics Data System (ADS)

    Giar, Ryan; Scharer, John

    2011-11-01

    Measurements and analysis of air breakdown processes and plasma production by focusing 193 nm, 300 mJ, 15 MW high power laser radiation inside a 6 cm diameter helical radio frequency (RF) coil are presented. Quantum resonant multi-photon ionization (REMPI) and collisional cascade laser ionization processes are exploited that have been shown to produce high-density (ne ˜ 7 × 1016/cm3) cylindrical seed plasmas at 760 Torr. Air breakdown in lower pressures (from 7-22 Torr), where REMPI is the dominant laser ionization process, is investigated using an UV 18 cm focal length lens, resulting in a laser flux of 5.5 GW/cm2 at the focal spot. The focused laser power absorption and associated shock wave produce seed plasmas for sustainment by the RF (5 kW incident power, 1.5 s) pulse. Measurements of the helical RF antenna load impedance in the inductive and capacitive coupling regimes are obtained by measuring the loaded antenna reflection coefficient. A 105 GHz interferometer is used to measure the plasma electron density and collision frequency. Spectroscopic measurements of the plasma and comparison with the SPECAIR code are made to determine translational, rotational, and vibrational neutral temperatures and the associated neutral gas temperature. From this and the associated measurement of the gas pressure the electron temperature is obtained. Experiments show that the laser-formed seed plasma allows RF sustainment at higher initial air pressures (up to 22 Torr) than that obtained via RF-only initiation (<18 Torr) by means of a 0.3 J UV laser pulse.

  3. Focused excimer laser initiated, radio frequency sustained high pressure air plasmas

    SciTech Connect

    Giar, Ryan; Scharer, John

    2011-11-15

    Measurements and analysis of air breakdown processes and plasma production by focusing 193 nm, 300 mJ, 15 MW high power laser radiation inside a 6 cm diameter helical radio frequency (RF) coil are presented. Quantum resonant multi-photon ionization (REMPI) and collisional cascade laser ionization processes are exploited that have been shown to produce high-density (n{sub e} {approx} 7 x 10{sup 16}/cm{sup 3}) cylindrical seed plasmas at 760 Torr. Air breakdown in lower pressures (from 7-22 Torr), where REMPI is the dominant laser ionization process, is investigated using an UV 18 cm focal length lens, resulting in a laser flux of 5.5 GW/cm{sup 2} at the focal spot. The focused laser power absorption and associated shock wave produce seed plasmas for sustainment by the RF (5 kW incident power, 1.5 s) pulse. Measurements of the helical RF antenna load impedance in the inductive and capacitive coupling regimes are obtained by measuring the loaded antenna reflection coefficient. A 105 GHz interferometer is used to measure the plasma electron density and collision frequency. Spectroscopic measurements of the plasma and comparison with the SPECAIR code are made to determine translational, rotational, and vibrational neutral temperatures and the associated neutral gas temperature. From this and the associated measurement of the gas pressure the electron temperature is obtained. Experiments show that the laser-formed seed plasma allows RF sustainment at higher initial air pressures (up to 22 Torr) than that obtained via RF-only initiation (<18 Torr) by means of a 0.3 J UV laser pulse.

  4. Structure of an Exploding Laser-Produced Plasma

    SciTech Connect

    Collette, A.; Gekelman, W.

    2010-11-05

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

  5. Structure of an exploding laser-produced plasma

    SciTech Connect

    Collette, A.; Gekelman, W.

    2011-05-15

    Currents and instabilities associated with an expanding dense plasma embedded in a magnetized background plasma are investigated by direct volumetric probe measurements of the magnetic field and floating potential. A diamagnetic cavity is formed and found to collapse rapidly compared to the expected magnetic diffusion time. The three-dimensional current density within the expanding plasma includes currents along the background magnetic field, in addition to the diamagnetic current. Correlation measurements reveal that flutelike structures at the plasma surface translate with the expanding plasma across the magnetic field and extend into the current system that sustains the diamagnetic cavity, possibly contributing to its collapse.

  6. Structure of an exploding laser-produced plasma.

    PubMed

    Collette, A; Gekelman, W

    2010-11-01

    We describe the first-ever volumetric, time-resolved measurements performed with a moving probe within an expanding dense plasma, embedded in a background magnetized plasma. High-resolution probe measurements of the magnetic field and floating potential in multiple 2D cut planes combined with a 1 Hz laser system reveal complex three-dimensional current systems within the expanding plasma. Static (?real=0) flutelike density striations are observed at the leading edge of the plasma, which are correlated to variations in the current layer at the edge of the expanding plasma. PMID:21231174

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

    SciTech Connect

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

    2001-09-19

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

  8. Parameters of atmospheric plasmas produced by electrosurgical devices

    NASA Astrophysics Data System (ADS)

    Keidar, Michael; Shashurin, Alexey; Canady, Jerome

    2013-10-01

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

  9. Metallic nanocluster formation in neutral gas-confined laser produced plasma afterglow

    SciTech Connect

    Kim, Yong W.; Lee, Hedok; Belony, Paul Jr.

    2006-10-15

    Dense atom vapors are created as remnants of a three-dimensional (3D) laser-produced plasma (LPP) plume driven from a solid aluminum target by a gigawatt-class Nd:glass laser pulse. Formation of nanoclusters as the terminal state of aluminum vapors has been investigated. By plasma structure diagnosis, we have fully characterized the LPP plume in 3D as a function of time and from its evolution modeled its cooling to the critical point in more than 110 000 vapor cells. Clustering of atoms is calculated by numerical simulation of interparticle collisions. When the cluster size histogram is rescaled relative to the maximum population and the maximal radius, the rescaled histograms all collapse into a single functional form regardless of the time or the initial atom vapor density. The cluster size distribution for the entire plasma plume is obtained by summing over all plasma cells. Independently, the clusters are captured onto electron microscope grids and size analyzed by means of transmission electron microscopy. The computed result is in excellent agreement with the measured histograms of clusters by size.

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

    NASA Astrophysics Data System (ADS)

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

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

  11. Characterization of linear plasma synthetic jet actuators in an initially quiescent medium

    NASA Astrophysics Data System (ADS)

    Santhanakrishnan, Arvind; Reasor, Daniel A.; LeBeau, Raymond P.

    2009-04-01

    The plasma synthetic jet actuator (PSJA) is a geometrical variant of the aerodynamic plasma actuator that can be used to produce zero-mass flux jets similar to those created by mechanical devices. This jet can be either three-dimensional using annular electrode arrays (annular PSJA) or nearly two dimensional using two rectangular-strip exposed electrodes and one embedded electrode (linear PSJA). Unsteady pulsing of the PSJA at time scales decoupled to the ac input frequency results in a flow field dominated by counter-rotating vortical structures similar to conventional synthetic jets, and the peak velocity and momentum of the jet is found to be affected by a combination of the pulsing frequency and input power. This paper investigates the fluid dynamic characteristics of linear plasma synthetic jet actuators in an initially quiescent medium. Two-dimensional particle image velocimetry measurements on the actuator are used to validate a previously developed numerical model wherein the plasma behavior is introduced into the Navier-Stokes equations as an electrohydrodynamic force term calculated from Maxwell's equations and solved for the fluid momentum. The numerical model was implemented in an incompressible, unstructured grid code. The results of the simulations are observed to reproduce some aspects of the qualitative and quantitative experimental behavior of the jet for steady and pulsed modes of actuator operation. The self-similarity behavior of plasma synthetic jets are examined and compared to mechanically driven continuous and synthetic jets.

  12. Characterization of linear plasma synthetic jet actuators in an initially quiescent medium

    SciTech Connect

    Santhanakrishnan, Arvind; Reasor, Daniel A. Jr.; LeBeau, Raymond P. Jr.

    2009-04-15

    The plasma synthetic jet actuator (PSJA) is a geometrical variant of the aerodynamic plasma actuator that can be used to produce zero-mass flux jets similar to those created by mechanical devices. This jet can be either three-dimensional using annular electrode arrays (annular PSJA) or nearly two dimensional using two rectangular-strip exposed electrodes and one embedded electrode (linear PSJA). Unsteady pulsing of the PSJA at time scales decoupled to the ac input frequency results in a flow field dominated by counter-rotating vortical structures similar to conventional synthetic jets, and the peak velocity and momentum of the jet is found to be affected by a combination of the pulsing frequency and input power. This paper investigates the fluid dynamic characteristics of linear plasma synthetic jet actuators in an initially quiescent medium. Two-dimensional particle image velocimetry measurements on the actuator are used to validate a previously developed numerical model wherein the plasma behavior is introduced into the Navier-Stokes equations as an electrohydrodynamic force term calculated from Maxwell's equations and solved for the fluid momentum. The numerical model was implemented in an incompressible, unstructured grid code. The results of the simulations are observed to reproduce some aspects of the qualitative and quantitative experimental behavior of the jet for steady and pulsed modes of actuator operation. The self-similarity behavior of plasma synthetic jets are examined and compared to mechanically driven continuous and synthetic jets.

  13. Persistence of uranium emission in laser-produced plasmas

    SciTech Connect

    LaHaye, N. L.; Harilal, S. S. Diwakar, P. K.; Hassanein, A.

    2014-04-28

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

  14. Diagnostics Techniques of Plasmas Produced by Laser Ablation

    SciTech Connect

    Villagran Muniz, M.; Sobral, H.; Sanchez Ake, C.; Sangines de Castro, R.; Sterling, E.; Bredice, F.

    2005-04-21

    Laser ablation in addition for thin film growing is also used for analytical techniques as Laser Induced Breakdown Spectroscopy and for applications as simulation of natural lightning. In this work we present several diagnostic techniques such as probe beam deflection, shadowgraphy, interferometry, pulsed laser photoacoustic and the electrical perturbation induced by laser ablation plasmas that's gives essential information of the plasma, hot core air and shock wave expansion.

  15. Initial study of the optical spectrum of the ISIS H{sup -} ion source plasma

    SciTech Connect

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

    2012-02-15

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

  16. Plasma observations near Jupiter - Initial results from Voyager 2

    NASA Technical Reports Server (NTRS)

    Bridge, H. S.; Belcher, J. W.; Lazarus, A. J.; Sullivan, J. D.; Bagenal, F.; Mcnutt, R. L., Jr.; Ogilvie, K. W.; Scudder, J. D.; Sittler, E. D.; Vasyliunas, V. M.

    1979-01-01

    A preliminary report is presented of the results obtained by the Voyager 2 plasma experiment during the encounter of Voyager 2 with Jupiter from about 100 Jupiter radii before periapsis to about 300 Jupiter radii after periapsis, the instrument being identical to that on Voyager 1. The discussion covers the following: (1) the crossings of the bow shock and magnetopause observed on the inbound and outbound passes; (2) the radial variation of plasma properties in the magnetosphere; (3) variations in plasma properties near Ganymede; (4) corotation and composition of the plasma in the dayside magnetosphere; and (5) plasma sheet crossings observed on the inbound and outbound passes. From the planetary spin modulation of the plasma-electron intensity it is inferred that the plasma sheet is centered at the dipole magnetic equator out to a distance of 40-50 Jupiter radii and deviates from it toward the rotational equator at larger distances.

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

    NASA Technical Reports Server (NTRS)

    Auer, Siegfried

    1994-01-01

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

  18. Research on plasma-puff initiation of high Coulomb transfer switches

    NASA Technical Reports Server (NTRS)

    Venable, Demetrius D.; Han, Kwang S.

    1993-01-01

    The plasma-puff triggering mechanism based on hypocycloidal pinch geometry was investigated to determine the optimal operating conditions for an azimuthally uniform surface flashover which initiates plasma-puff under wide ranges of fill gas pressures of Ar, He and N2. Research is presented and resulting conference papers are attached. These papers include 'Characteristics of Plasma-Puff Trigger for an Inverse-Pinch Plasma Switch'; 'Ultra-High-Power Plasma Switch INPUTS for Pulse Power Systems'; 'Characteristics of Switching Plasma in an Inverse-Pinch Switch'; 'Comparative Study of INPIStron and Spark Gap'; and 'INPIStron Switched Pulsed Power for Dense Plasma Pinches.'

  19. Characterization of laser-produced fusion plasmas with thomson scattering

    SciTech Connect

    Glenzer, S.H.; Back, C.A.; Suter, L.J.; MacGowan, B.J.; Landen, O.L.; Lindl, J.D.; Blain, M.A.

    1997-07-09

    Thomson scattering has been developed at the Nova laser facility as a direct and accurate diagnostic to characterize inertial confinement fusion plasmas. Measurements from methane-filled, ignition relevant hohlraums apply the theory for two ion species plasmas, which has been tested in separate open geometry experiments, to obtain electron and ion temperatures. The experimental data provide a benchmark for two-dimensional hydrodynamic simulations using LASNEX, which is presently in use to predict he performance of future megajoule laser- driven hohlraums of the National Ignition Facility (NIF). The data are consistent with modeling using significantly inhibited heat transport at the peak of the drive. Furthermore, we find that stagnating plasma regions on the hohlraum axis are well described by the calculations. The result implies that stagnation in gas-filled hohlraums occurs too late to directly affect the capsule implosion in ignition experiments.

  20. Suprathermal electrons produced by beam-plasma-discharge

    NASA Technical Reports Server (NTRS)

    Sharp, W. E.

    1982-01-01

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

  1. Generation of collisionless shock in laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Fiuza, Frederico

    2015-08-01

    Collisionless shocks are ubiquitous in astrophysical environments and are tightly connected with magnetic-field amplification and particle acceleration. The fast progress in high-power laser technology is bringing the study of high Mach number shocks into the realm of laboratory plasmas, where in situ measurements can be made helping us understand the fundamental kinetic processes behind shocks. I will discuss the recent progress in laser-driven shock experiments at state-of-the-art facilities like NIF and Omega and how these results, together with ab initio massively parallel simulations, can impact our understanding of magnetic field amplification and particle acceleration in astrophysical plasmas.

  2. Parametric processes in underdense UV laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Tanaka, K.; Boswell, B.; Craxton, R. S.; Goldman, L. M.; Seka, W.; Short, R. W.; Soures, J. M.; Bahr, R.; Guglielmi, F.

    1984-10-01

    Studies of UV laser plasma interactions in underdense plasmas, using a single beam (lambda sub L) = 351-nm, E (sub L) 50 J, I (sub L) is less than or equal to (10 to the 15th power W/sq cm) incident on foam targets are described. Average densities of these targets were 2n (sub c)/3, n (sub c)/3 and n (sub c)/10 (n (sub c): critical density). An extraordinary correlation between the Brillouin backscatter signal and the 3(OMEGA)/2 emission as a function of irradiation intensity was observed, indicative of possible coupling between these parametric processes.

  3. Suprathermal electrons produced by Beam-Plasma-Discharge

    SciTech Connect

    Sharp, W.E.

    1982-08-01

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

  4. A comparison of plasma waves produced by ion accelerators in the F-region ionosphere

    NASA Technical Reports Server (NTRS)

    Kintner, P. M.; Labelle, J.; Scales, W.; Erlandson, R.; Cahill, L. J., Jr.

    1986-01-01

    Ion beams injected into the ionosphere are known to produce waves related to the normal modes of the plasma. The spectra of plasma waves produced during four sounding rocket experiments are examined. The experimental conditions were somewhat different during each experiment. The accelerated ion was either Xe(+) or Ar(+) and the experimental geometry, described by the separation vector between the plasma wave receiver and the ion accelerator, was either parallel or perpendicular to the geomagnetic field.

  5. Plasma choline metabolites and colorectal cancer risk in the Women's Health Initiative Observational Study.

    PubMed

    Bae, Sajin; Ulrich, Cornelia M; Neuhouser, Marian L; Malysheva, Olga; Bailey, Lynn B; Xiao, Liren; Brown, Elissa C; Cushing-Haugen, Kara L; Zheng, Yingye; Cheng, Ting-Yuan David; Miller, Joshua W; Green, Ralph; Lane, Dorothy S; Beresford, Shirley A A; Caudill, Marie A

    2014-12-15

    Few studies have examined associations between plasma choline metabolites and risk of colorectal cancer. Therefore, we investigated associations between plasma biomarkers of choline metabolism [choline, betaine, dimethylglycine, and trimethylamine N-oxide (TMAO)] and colorectal cancer risk among postmenopausal women in a case-control study nested within the Women's Health Initiative Observational Study. We selected 835 matched case-control pairs, and cases were further stratified by tumor site (proximal, distal, or rectal) and stage (local/regional or metastatic). Colorectal cancer was assessed by self-report and confirmed by medical records over the mean of 5.2 years of follow-up. Baseline plasma choline metabolites were measured by LC/MS-MS. In multivariable-adjusted conditional logistic regression models, plasma choline tended to be positively associated with rectal cancer risk [OR (95% confidence interval, CI)(highest vs. lowest quartile) = 2.44 (0.93-6.40); P trend = 0.08], whereas plasma betaine was inversely associated with colorectal cancer overall [0.68 (0.47-0.99); P trend = 0.01] and with local/regional tumors [0.64 (0.42-0.99); P trend = 0.009]. Notably, the plasma betaine:choline ratio was inversely associated with colorectal cancer overall [0.56 (0.39-0.82); P trend = 0.004] as well as with proximal [0.66 (0.41-1.06); P trend = 0.049], rectal [0.27 (0.10-0.78); P trend = 0.02], and local/regional [0.50 (0.33-0.76); P trend = 0.001] tumors. Finally, plasma TMAO, an oxidative derivative of choline produced by intestinal bacteria, was positively associated with rectal cancer [3.38 (1.25-9.16); P trend = 0.02] and with overall colorectal cancer risk among women with lower (vs. higher) plasma vitamin B12 levels (P interaction = 0.003). Collectively, these data suggest that alterations in choline metabolism, which may arise early in disease development, may be associated with higher risk of colorectal cancer. The positive association between plasma TMAO and colorectal cancer risk is consistent with an involvement of the gut microbiome in colorectal cancer pathogenesis. PMID:25336191

  6. Plasma choline metabolites and colorectal cancer risk in the Women’s Health Initiative Observational Study

    PubMed Central

    Bae, Sajin; Ulrich, Cornelia M.; Neuhouser, Marian L.; Malysheva, Olga; Bailey, Lynn B.; Xiao, Liren; Brown, Elissa C.; Cushing-Haugen, Kara L.; Zheng, Yingye; Cheng, Ting-Yuan David; Miller, Joshua W.; Green, Ralph; Lane, Dorothy S.; Beresford, Shirley A. A.; Caudill, Marie A.

    2014-01-01

    Few studies have examined associations between plasma choline metabolites and risk of colorectal cancer (CRC). Therefore, we investigated associations between plasma biomarkers of choline metabolism [choline, betaine, dimethylglycine and trimethylamine N-oxide (TMAO)] and CRC risk among postmenopausal women in a case-control study nested within the Women’s Health Initiative Observational Study. We selected 835 matched case-control pairs, and cases were further stratified by tumor site (proximal, distal, or rectal) and stage (local/regional or metastatic). CRC was assessed by self-report and confirmed by medical records over the mean 5.2y of follow-up. Baseline plasma choline metabolites were measured by liquid chromatography-tandem mass spectrometry. In multivariable-adjusted conditional logistic regression models, plasma choline tended to be positively associated with rectal cancer risk [OR (95% CI)highest vs. lowest quartile=2.44 (0.93–6.40);P-trend=0.08], while plasma betaine was inversely associated with CRC overall [0.68 (0.47–0.99);P-trend=0.01] and with local/regional tumors [0.64 (0.42–0.99);P-trend=0.009]. Notably, the plasma betaine:choline ratio was inversely associated with CRC overall [0.56 (0.39–0.82);P-trend=0.004] as well as with proximal [0.66 (0.41–1.06);P-trend=0.049], rectal [0.27 (0.10–0.78);P-trend=0.02] and local/regional [0.50 (0.33–0.76);P-trend=0.001] tumors. Finally, plasma TMAO, an oxidative derivative of choline produced by intestinal bacteria, was positively associated with rectal cancer [3.38 (1.25–9.16);P-trend=0.02] and with overall CRC risk among women with lower (vs. higher) plasma vitamin B12 levels (P-interaction=0.003). Collectively, these data suggest that alterations in choline metabolism, which may arise early in disease development, may be associated with higher risk of CRC. The positive association between plasma TMAO and CRC risk is consistent with an involvement of the gut microbiome in CRC pathogenesis. PMID:25336191

  7. Plasma conditions produced in long-implosion-time z pinches

    NASA Astrophysics Data System (ADS)

    Failor, B. K.; Song, Y.; Levine, J. S.; Riordan, J. C.; Coleman, P. L.; Yadlowsky, E. J.; Hazelton, R. C.; Moschella, J. J.; Deeney, C.; Coverdale, C. A.; Apruzese, J. P.

    1998-11-01

    We have diagnosed 200-300 nsec implosion time Ar z-pinches at the DECADE Module 2, Double EAGLE, and SATURN facilities. Extending the implosion time beyond 100 ns reduces the complexity of z-pinch drivers for future high current (> 20 MA) facilities. Our objective is to characterize the hot, dense pinch core plasma where 10^19 < ne < 10^22 e/cm^3 and 0.5 < Te < 2.0 keV. We estimate plasma conditions from the K-shell spectra of both the primary gas, Ar, and a dopant, Cl. Ti is found from Doppler broadening. Imaging slits allow us to measure the axial and radial variation in the density and temperature profiles.

  8. Topical applications of resonance internal conversion in laser produced plasma

    NASA Astrophysics Data System (ADS)

    Karpeshin, F. F.

    2007-04-01

    Physical aspects of resonance effects arising in plasma due to interactions of nuclei with the electrons are considered. Among them are resonance conversion (TEEN) and the reverse process of NEET. These processes are of great importance for pumping the excited nuclear states (isomers) and for accelerating their decay. Experiment is discussed on studying the unique 3.5-eV 229m Th nuclide.

  9. Astrophysical Weibel instability in counterstreaming laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Fox, William; Fiksel, Gennady; Bhattacharjee, Amitava; Change, Po-Yu; Germaschewski, Kai; Hu, Suxing; Nilson, Philip

    2014-06-01

    Astrophysical shock waves play diverse roles, including energizing cosmic rays in the blast waves of astrophysical explosions, and generating primordial magnetic fields during the formation of galaxies and clusters. These shocks are typically collisionless and require collective electromagnetic fields to couple the upstream and downstream plasmas. The Weibel instability has been proposed to provide the requisite interaction mechanism for shock formation in weakly-magnetized shocks by generating turbulent electric and magnetic fields in the shock front. This work presents the first laboratory identification of this Weibel instability between counterstreaming supersonic plasma flows and confirms its basic features, a significant step towards understanding these shocks. In the experiments, conducted on the OMEGA EP laser facility at the University of Rochester, a pair of plasmas plumes are generated by irradiating of a pair of opposing parallel plastic (CH) targets. The ion-ion interaction between the two plumes is collisionless, so as the plumes interpenetrate, supersonic, counterstreaming ion flow conditions are obtained. Electromagnetic fields formed in the interaction of the two plumes were probed with an ultrafast laser-driven proton beam, and we observed the growth of a highly striated, transverse instability with extended filaments parallel to the flows. The instability is identified as an ion-driven Weibel instability through agreement with analytic theory and particle-in-cell simulations, paving the way for further detailed laboratory study of this instability and its consequences for particle energization and shock formation.[1] W. Fox, G. Fiksel, A. Bhattacharjee, P. Y. Chang, K. Germaschewski, S. X. Hu, and P. M. Nilson, “Filamentation instability of counterstreaming laser-driven plasmas,” Phys. Rev. Lett. 111, 225002 (2013).

  10. Diagnostics of silicon plasmas produced by visible nanosecond laser ablation

    NASA Astrophysics Data System (ADS)

    Miln, M.; Laserna, J. J.

    2001-03-01

    The second harmonic of a pulsed Nd:YAG laser (532 nm) has been used for the ablation of silicon samples in air at atmospheric pressure. In order to study the interaction for silicon targets, the laser-induced plasma characteristics were examined in detail with the use of a space- and time-resolved technique. Electron temperatures, ionic temperatures and electron number densities were determined. A discussion of thermodynamic equilibrium status of the silicon-microplasma is presented. Electron number densities are deduced from the Stark broadening of the line profiles of atomic silicon. Plasma ionization and excitation temperatures were determined from the Boltzmann plot and the Saha-Boltzmann equation, respectively. A limited number of suitable silicon lines for the studies of temperatures were found and the effect of these lines on the temperature measurements is discussed. Electron temperatures in the range of 6000-9000 K and ionic temperatures of 12 000-17 000 K with electron number densities of the order of 10 18 cm -3 were observed. The breakdown threshold fluence has been also measured. Silicon plasmas were also characterized in terms of their morphology (shape and size) as a function of laser energy and delay time.

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

    NASA Technical Reports Server (NTRS)

    Bridge, H. S.; Belcher, J. W.; Lazarus, A. J.; Olbert, S.; Sullivan, J. D.; Bagenal, F.; Gazis, P. R.; Hartle, R. E.; Ogilvie, K. W.; Scudder, J. D.

    1981-01-01

    The Voyager 1 encounter with Saturn and its satellites yielded extensive measurements of magnetospheric low-energy plasma electrons and positive ions, both heavy and light, probably of hydrogen and nitrogen or oxygen. At radial distances between 15 and 7 Saturn radii on the inbound trajectory, the plasma appears to corotate with a velocity within 20% of that theoretically expected for rigid corotation. The Titan data, taken while the moon was inside the Saturn magnetosphere, shows a clear signature characteristic of the interaction between a subsonic corotating magnetospheric plasma and the atmospheric or ionospheric exosphere of Titan.

  12. Jupiter plasma wave observations: an initial voyager 1 overview.

    PubMed

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

    1979-06-01

    The Voyager I plasma wave instrument detected low-frequency radio emissions, ion acoustic waves, and electron plasma oscillations for a period of months before encountering Jupiter's bow shock. In the outer magnetosphere, measurements of trapped radio waves were used to derive an electron density profile. Near and within the Io plasma torus the instrument detected high-frequency electrostatic waves, strong whistler mode turbulence, and discrete whistlers, apparently associated with lightning. Some strong emissions in the tail region and some impulsive signals have not yet been positively identified. PMID:17800437

  13. Analysis of plasma distribution near the extraction region in surface produced negative ion sources

    NASA Astrophysics Data System (ADS)

    Fukano, A.; Hatayama, A.

    2014-02-01

    In study of a negative ion source, it is important to understand the plasma characteristics near the extraction region. A recent experiment in the NIFS-R&D ion source has suggested that a "double ion plasma layer" which is a region consisting of hydrogen positive and negative ions exists near the plasma grid (PG). Density distribution of plasma near the extraction region is studied analytically. It is shown that the density distribution depends on an amount of the surface produced negative ions and the double ion plasma layer is formed near the PG surface for the case of strong surface production.

  14. Analysis of plasma distribution near the extraction region in surface produced negative ion sources.

    PubMed

    Fukano, A; Hatayama, A

    2014-02-01

    In study of a negative ion source, it is important to understand the plasma characteristics near the extraction region. A recent experiment in the NIFS-R&D ion source has suggested that a "double ion plasma layer" which is a region consisting of hydrogen positive and negative ions exists near the plasma grid (PG). Density distribution of plasma near the extraction region is studied analytically. It is shown that the density distribution depends on an amount of the surface produced negative ions and the double ion plasma layer is formed near the PG surface for the case of strong surface production. PMID:24593563

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

    SciTech Connect

    Dunn, J; Filevich, J; Smith, R F; Moon, S J; Rocca, J J; Keenan, R; Nilsen, J; Shlyaptsev, V N; Hunter, J R; Ng, A; Marconi, M C

    2004-10-14

    We have developed a compact, 14.7 nm, sub-5 ps x-ray laser source at LLNL together with a Mach-Zehnder type Diffraction Grating Interferometer built at Colorado State University for probing dense, high intensity laser-produced plasmas. The short wavelength and pulse length of the probe reduces refraction and absorption effects within the plasma and minimizes plasma motion blurring. This unique diagnostic capability gives precise 2-D density profile snapshots and is generating new data for rapidly evolving laser-heated plasmas. A review of the results from dense, mm-scale line focus plasma experiments will be described with detailed comparisons to hydrodynamic simulations.

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

  18. Plasma observations near saturn: initial results from voyager 2.

    PubMed

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

    1982-01-29

    Results of measurements of plasma electrons and poitive ions made during the Voyager 2 encounter with Saturn have been combined with measurements from Voyager 1 and Pioneer 11 to define more clearly the configuration of plasma in the Saturnian magnetosphere. The general morphology is well represented by four regions: (i) the shocked solar wind plasma in the magnetosheath, observed between about 30 and 22 Saturn radii (RS) near the noon meridian; (ii) a variable density region between approximately 17 RS and the magnetopause; (iii) an extended thick plasma sheet between approximately 17 and approximately 7 RS symmetrical with respect to Saturn's equatorial plane and rotation axis; and (iv) an inner plasma torus that probably originates from local sources and extends inward from L approximately 7 to less than L approximately 2.7 (L is the magnetic shell parameter). In general, the heavy ions, probably O(+), are more closely confined to the equatorial plane than H(+), so that the ratio of heavy to light ions varies along the trajectory according to the distance of the spacecraft from the equatorial plane. The general configuration of the plasma sheet at Saturn found by Voyager 1 is confirmed, with some notable differences and additions. The "extended plasma sheet," observed between L approximately 7 and L approximately 15 by Voyager 1 is considerably thicker as observed by Voyager 2. Inward of L approximately 4, the plasma sheet collapses to a thin region about the equatorial plane. At the ring plane crossing, L approximately 2.7, the observations are consistent with a density of O(+) of approximately 100 per cubic centimeter, with a temperature of approximately 10 electron volts. The location of the bow shock and magnetopause crossings were consistent with those previously observed. The entire magnetosphere was larger during the outbound passage of Voyager 2 than had been previously observed; however, a magnetosphere of this size or larger is expected approximately 3 percent of the time. PMID:17771279

  19. Ion beam and plasma methods of producing diamondlike carbon films

    NASA Technical Reports Server (NTRS)

    Swec, Diane M.; Mirtich, Michael J.; Banks, Bruce A.

    1988-01-01

    A variety of plasma and ion beam techniques was employed to generate diamondlike carbon films. These methods included the use of RF sputtering, dc glow discharge, vacuum arc, plasma gun, ion beam sputtering, and both single and dual ion beam deposition. Since films were generated using a wide variety of techniques, the physico-chemical properties of these films varied considerably. In general, these films had characteristics that were desirable in a number of applications. For example, the films generated using both single and dual ion beam systems were evaluated for applications including power electronics as insulated gates and protective coatings on transmitting windows. These films were impervious to reagents which dissolve graphitic and polymeric carbon structures. Nuclear reaction and combustion analysis indicated hydrogen to carbon ratios to be 1.00, which allowed the films to have good transmittance not only in the infrared, but also in the visible. Other evaluated properties of these films include band gap, resistivity, adherence, density, microhardness, and intrinsic stress. The results of these studies and those of the other techniques for depositing diamondlike carbon films are presented.

  20. Influence of target geometry on the ion temperature of laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Zheng, J.; Wang, Z. B.; Yu, C. X.; Jiang, X. H.; Cao, Z. R.; Ding, Y. K.; Tanaka, K. A.

    2008-05-01

    Thomson scattering measurements of laser-produced plasmas have been performed with a 4? probe beam in Shenguang II laser facility. Three kinds of the targets are irradiated with 3? laser beams: disc target, curved target, and void hohlraum. Thomson scattering spectra are quite different with the different targets. The two ion-acoustic resonance peaks become much broader when a curved target or a hohlraum is irradiated. The experimental results show that the target geometry has a strong influence on the ion temperature of the laser-produced plasmas. The ion temperature could be about several ten keV in the plasma produced with curved target or hohlraum.

  1. Angular distribution and forward peaking of laser produced plasma ions

    NASA Astrophysics Data System (ADS)

    Shahid Rafique, M.; Khaleeq-Ur-Rahman, M.; Shahbaz Anwar, Muhammad; Mahmood Afshan Ashfaq, Faryaal; Siraj, Khurram

    2005-04-01

    This paper represents the results of a study of angular distribution of laser produced ions (LPI) of Al, Cu, and Ag. The angular distribution is studied by CR-39 (SSNTD) and ion assisted sputtering experiments. A Q-Switched Nd:YAG laser (1.064 [mu]m, 1.1 MW) with 10 mJ pulsed energy was used to produce the Ag ions, which were detected by CR-39 detector mounted at [minus sign]17.5, 0, 17.5, 30, 60, and 90 from the normal to the target placed at a distance of 9 cm from the target. Etched CR-39 detectors then observed under the Motic DMB Series optical microscope. A bunch of ions was detected along the normal of target due to self generated collimation of ions. This is termed as Forward Peaking of Laser Produced Ions. Similar results were also observed from sputtering of polished Al substrate by laser produced ions of Cu and Sputtering of polished Cu substrate by laser produced ions of Al. The surface morphology of the ion irradiated samples were observed under the Scanning Electron microscope (SEM) S 300 Hi-tech. Formation of a circular damage on the surface of the substrates by irradiation conforms the ions collimation along the normal or Forward Peaking of ions.

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

    DOEpatents

    Bohachevsky, Ihor O.

    1981-01-01

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

  3. Quasi-steady-state air plasma channel produced by a femtosecond laser pulse sequence

    NASA Astrophysics Data System (ADS)

    Lu, Xin; Chen, Shi-You; Ma, Jing-Long; Hou, Lei; Liao, Guo-Qian; Wang, Jin-Guang; Han, Yu-Jing; Liu, Xiao-Long; Teng, Hao; Han, Hai-Nian; Li, Yu-Tong; Chen, Li-Ming; Wei, Zhi-Yi; Zhang, Jie

    2015-10-01

    A long air plasma channel can be formed by filamentation of intense femtosecond laser pulses. However, the lifetime of the plasma channel produced by a single femtosecond laser pulse is too short (only a few nanoseconds) for many potential applications based on the conductivity of the plasma channel. Therefore, prolonging the lifetime of the plasma channel is one of the key challenges in the research of femtosecond laser filamentation. In this study, a unique femtosecond laser source was developed to produce a high-quality femtosecond laser pulse sequence with an interval of 2.9?ns and a uniformly distributed single-pulse energy. The metre scale quasi-steady-state plasma channel with a 6080?ns lifetime was formed by such pulse sequences in air. The simulation study for filamentation of dual femtosecond pulses indicated that the plasma channel left by the previous pulse was weakly affected the filamentation of the next pulse in sequence under our experimental conditions.

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

    PubMed

    Quevedo, H J; McCormick, M; Wisher, M; Bengtson, Roger D; Ditmire, T

    2016-01-01

    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. PMID:26827309

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

    NASA Astrophysics Data System (ADS)

    Quevedo, H. J.; McCormick, M.; Wisher, M.; Bengtson, Roger D.; Ditmire, T.

    2016-01-01

    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.

  6. Treatment Characteristics of Polysaccharides and Endotoxin Using Oxygen Plasma Produced by RF Discharge

    SciTech Connect

    Kitazaki, Satoshi; Hayashi, Nobuya; Goto, Masaaki

    2010-10-13

    Treatment of polysaccharides and endotoxin were attempted using oxygen plasma produced by RF discharge. Oxygen radicals observed by optical light emission spectra are factors of decomposition of polysaccharides and endotoxin. Fourier transform infrared spectra indicate that most of chemical bonds in the polysaccharides are dissociated after irradiation of the oxygen plasma. Also, the decomposition rate of endotoxin was approximately 90% after irradiation of the oxygen plasma for 180 min.

  7. Plasma observations near Uranus - Initial results from Voyager 2

    NASA Technical Reports Server (NTRS)

    Bridge, H. S.; Belcher, J. W.; Coppi, B.; Lazarus, A. J.; Mcnutt, R. L., Jr.; Olbert, S.; Hartle, R. E.; Ogilvie, K. W.; Sittler, E. C., Jr.; Wolfe, R. S.

    1986-01-01

    The results of observations of the spatial distribution and physical properties of the space plasma near Uranus with instrumentation on board Voyager 2 are described. The data revealed the existence of a magnetosphere that held a warm component with a temperature of 4-50 eV and a peak density of 2 protons/cu cm and a hot component with a temperature of a few electron volts and a density of about 0.1 proton/cu cm. Only the warm component was observed within the L shell. The numerous crossings made of the plasma sheet in the magnetotail were at locations which suggested that the magnetotail has a geometric structure similar to that of the earth magnetotail. Finally, possible sources of the magnetospheric plasma particles are discussed.

  8. Plasma observations near Jupiter - Initial results from Voyager 1

    NASA Technical Reports Server (NTRS)

    Bridge, H. S.; Belcher, J. W.; Lazarus, A. J.; Sullivan, J. D.; Mcnutt, R. L.; Bagenal, F.; Scudder, J. D.; Sittler, E. C.; Siscoe, G. L.; Vasyliunas, V. M.

    1979-01-01

    Extensive measurements of low-energy positive ions and electrons were made throughout the Jupiter encounter of Voyager 1. The bow shock and magnetopause were crossed several times at distances consistent with variations in the upstream solar wind pressure measured on Voyager 2. During the inbound pass, the number density increased by six orders of magnitude between the innermost magnetopause crossing at approximately 47 Jupiter radii and near closest approach at approximately 5 Jupiter radii; the plasma flow during this period was predominately in the direction of corotation. Marked increases in number density were observed twice per planetary rotation, near the magnetic equator. Jupiterward of the Io plasma torus, a cold, corotating plasma was observed and the energy/charge spectra show well-resolved, heavy-ion peaks at mass-to-charge ratios equal to 8, 16, 32, and 64.

  9. Characteristics of shock wave from nanosecond laser-produced aluminum plasma in air

    NASA Astrophysics Data System (ADS)

    Liu, Tianhang; Gao, Xun; Liu, Zehao; Sun, Changkai; Hao, Zuoqiang; Jin, Guangyong; Lin, Jingquan

    2013-05-01

    Characteristics of shock wave as well as its evolution of aluminum plasma produced by nanosecond YAG laser is investigated by time-resolved optical shadowgraph images. Experimental results show that shock wave is strongly influenced by the laser parameters and target arrangement. Shock waves from aluminum plasma and air plasma are observed simultaneously by shadowgraphs when the distance from lens to target surface (DLTS) is longer than the lens focal length, and a narrow bright "line" is observed in the region where shock waves from Al plasma and air plasma meet. The longitudinal expansion velocity of shock wave from Al plasma is largely influenced by DLTS and laser intensity as well, and it increases with laser intensity at the early stage of plasma expansion and reach to a maximum of 8.1104 m/s.

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

    SciTech Connect

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

    2013-01-15

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

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

    SciTech Connect

    Grun, J.; Ripin, B.H.

    1982-12-01

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

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

    SciTech Connect

    Grun, J.; Ripin, B.H.

    1982-09-17

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

  13. Specific features of microheterogeneous plasma produced by irradiation of a polymer aerogel target with an intense 500-ps-long laser pulse

    SciTech Connect

    Borisenko, N. G.; Merkulev, Yu. A.; Orekhov, A. S.; Chaurasia, S.; Tripathi, S.; Munda, D. S.; Dhareshwar, L. J.; Pimenov, V. G.; Sheveleva, E. E.

    2013-08-15

    The properties of microheterogeneous plasma produced by irradiation of a polymer aerogel target with an intense (10{sup 14} W/cm{sup 3}) short (0.5 ps) 1.064-?m laser pulse were studied. It is found that, even at plasma densities exceeding the critical density, a small fraction of the incident laser radiation penetrates through the plasma in which the processes of density and temperature equalization still take place. The intensification (as compared to plasmas produced from denser foams and solid films) of transport processes in such plasma along and across the laser beam can be caused by the initial microheterogeneity of the solid target. The replacement of a small (10% by mass) part of the polymer with copper nanoparticles leads to a nearly twofold increase in the intensity of the plasma X-ray emission.

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

    SciTech Connect

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

    2012-09-15

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

  15. Four-color laser diagnostics for Z-pinch and laser-produced plasma.

    PubMed

    Ivanov, V V; Anderson, A A; Begishev, I A

    2016-01-20

    Four-color laser diagnostics were developed for Z-pinch and laser plasma at the 1MA pulsed power generator. Four harmonics of the Nd:YAG laser at wavelengths of 1064, 532, 266, and 213nm were produced during the cascade conversion in three nonlinear crystals and propagated together in one beampath. Deep UV probing allows better penetration of the dense plasma. Laser probing at four wavelengths allows observation of plasma in a wide range of densities in one shot of the diagnostic laser. Examples of four-color laser shadowgraphy and interferometry of the wire-array load and laser plasma interaction are presented and discussed. PMID:26835923

  16. Heating dynamics and extreme ultraviolet radiation emission of laser-produced Sn plasmas

    SciTech Connect

    Yuspeh, S.; Sequoia, K. L.; Tao, Y.; Tillack, M. S.; Burdt, R. A.; Najmabadi, F.

    2010-06-28

    The impact of 1.064 mum laser absorption depth on the heating and in-band (2% bandwidth) 13.5 nm extreme ultraviolet emissions in Sn plasmas is investigated experimentally and numerically. In-band emission lasting longer than the laser pulse and separation between the laser absorption and in-band emission region are observed. Maximum efficiency is achieved by additional heating of the core of the plasma to allow the optimal temperature to expand to a lower and more optically thin density. This leads to higher temperature plasma that emits less in-band light as compared to CO{sub 2} produced plasma sources for the same application.

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

    SciTech Connect

    Morita, T.; Kuramitsu, Y.; Moritaka, T.; Sakawa, Y.; Takabe, H.; Graduate School of Science, Osaka University, 1-1 Machikane-yama, Toyonaka, Osaka 560-0043 ; Tomita, K.; Nakayama, K.; Inoue, K.; Uchino, K.; Ide, T.; Tsubouchi, K.; Nishio, K.; Ide, H.; Kuwada, M.

    2013-09-15

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

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

    SciTech Connect

    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.

    2010-01-04

    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 approx100 fs is demonstrated, and the possibility to produce a sub-10 fs, high dynamic range 'all optical' streak camera is discussed.

  19. Hydrogen ions produced by plasma-assisted catalytic ionization using nickel grid

    SciTech Connect

    Oohara, W.; Kawata, K.; Hibino, T.

    2013-06-15

    Positive and negative hydrogen ions are produced by plasma-assisted catalytic ionization using a nickel grid, where the irradiation current density of positive ions onto the grid can be controlled by the discharge power. The irradiation energy can be controlled by both the grid potential and the discharge plasma potential. Extraction properties and energy distributions of positive and negative ions produced in the cases of using the grid and a porous nickel plate are compared. Two production mechanisms of negative ions are found in the process of plasma-assisted catalytic ionization.

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

    SciTech Connect

    Gielissen, K.; Mullen, J. J. A. M. v. d.; Sidelnikov, Y.; Glushkov, D.; Banine, V.; Soer, W. A.

    2010-01-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  2. Experimental Results from Initial Operation of Plasma Injector 1

    NASA Astrophysics Data System (ADS)

    Howard, Stephen

    2010-11-01

    General Fusion has begun operation of its first full-scale plasma injector, designed to accelerate high density spheromak plasmas into the compression chamber of a proposed MTF reactor. The geometry of Plasma Injector 1 (PI-1) is that of a two stage coaxial Marshal gun with a conical converging accelerator electrodes, similar in shape to the MARAUDER device, while pulsed power is applied in the same configuration as the RACE device. PI-1 is 5 meters in length and 1.9 m in diameter at the expansion region where a high aspect ratio (4.4) spheromak is formed with a minimum lambda of 9 m-1. The acceleration/compression stage is 4 m long and tapers to a final outer diameter of 40 cm. PI-1 is now operating at 1 MJ of total capacitor power, which will be doubled again before it reaches its design parameters. Diagnostics include 3 interferometer chords, 21 magnetic probes (2 axis poloidal/toroidal), 13 fast photodiode chords, as well as one Thomson scattering chord, a visible light survey spectrometer, and a Langmuir triple probe. Electrode voltage and current are also monitored. So far spheromaks of poloidal flux exceeding 100 mWb have been formed in the expansion region, and spheromaks of 40-50 mWb have been formed and accelerated out the end of the accelerator into a flux conserving target chamber. Expansion region densities are typically 5 x10^14cm-3, while conditions in the target chamber have reached ne10^16cm-3, and lifetimes of 300 ?s.

  3. Inactivation of Shiga toxin-producing Escherichia coli O104:H4 using cold atmospheric pressure plasma.

    PubMed

    Baier, Matthias; Janssen, Traute; Wieler, Lothar H; Ehlbeck, Jrg; Knorr, Dietrich; Schlter, Oliver

    2015-09-01

    From cultivation to the end of the post-harvest chain, heat-sensitive fresh produce is exposed to a variety of sources of pathogenic microorganisms. If contaminated, effective gentle means of sanitation are necessary to reduce bacterial pathogen load below their infective dose. The occurrence of rare or new serotypes raises the question of their tenacity to inactivation processes. In this study the antibacterial efficiency of cold plasma by an atmospheric pressure plasma-jet was examined against the Shiga toxin-producing outbreak strain Escherichia coli O104:H4. Argon was transformed into non-thermal plasma at a power input of 8W and a gas flow of 5Lmin(-1). Basic tests were performed on polysaccharide gel discs, including the more common E.coli O157:H7 and non-pathogenic E.coli DSM 1116. At 5mm treatment distance and 10(5)cfucm(-2) initial bacterial count, plasma reduced E.coli O104:H4 after 60s by 4.60.6 log, E.coli O157:H7 after 45s by 4.50.6 log, and E.coli DSM 1116 after 30s by 4.41.1 log. On the surface of corn salad leaves, gentle plasma application at 17mm reduced 10(4)cfucm(-2) of E.coli O104:H4 by 3.31.1 log after 2min, whereas E.coli O157:H7 was inactivated by 3.21.1 log after 60s. In conclusion, plasma treatment has the potential to reduce pathogens such as E.coli O104:H4 on the surface of fresh produce. However, a serotype-specific adaptation of the process parameters is required. PMID:25782617

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

    SciTech Connect

    Sizyuk, Tatyana; Hassanein, Ahmed

    2014-08-15

    Photon sources produced by laser beams with moderate laser intensities, up to 10{sup 14 }W/cm{sup 2}, are being developed for many industrial applications. The performance requirements for high volume manufacture devices necessitate extensive experimental research supported by theoretical plasma analysis and modeling predictions. We simulated laser produced plasma sources currently being developed for several applications such as extreme ultraviolet lithography using 13.5% ± 1% nm bandwidth, possibly beyond extreme ultraviolet lithography using 6.× nm wavelengths, and water-window microscopy utilizing 2.48 nm (La-α) and 2.88 nm (He-α) emission. We comprehensively modeled plasma evolution from solid/liquid tin, gadolinium, and nitrogen targets as three promising materials for the above described sources, respectively. Results of our analysis for plasma characteristics during the entire course of plasma evolution showed the dependence of source conversion efficiency (CE), i.e., laser energy to photons at the desired wavelength, on plasma electron density gradient. Our results showed that utilizing laser intensities which produce hotter plasma than the optimum emission temperatures allows increasing CE for all considered sources that, however, restricted by the reabsorption processes around the main emission region and this restriction is especially actual for the 6.× nm sources.

  5. Apparatus for recording emissions from a rapidly generated plasma from a single plasma producing event

    SciTech Connect

    Tan, T.H.; Williams, A.H.

    1985-09-17

    An optical fiber-coupled detector visible streak camera plasma diagnostic apparatus. Arrays of optical fiber-coupled detectors are placed on the film plane of several types of particle, x-ray and visible spectrometers or directly in the path of the emissions to be measured and the output is imaged by a visible streak camera. Time and spatial dependence of the emission from plasmas generated from a single pulse of electromagnetic radiation or from a single particle beam burst can be recorded.

  6. Apparatus for recording emissions from a rapidly generated plasma from a single plasma producing event

    DOEpatents

    Tan, Tai Ho (Los Alamos, NM); Williams, Arthur H. (Los Alamos, NM)

    1985-01-01

    An optical fiber-coupled detector visible streak camera plasma diagnostic apparatus. Arrays of optical fiber-coupled detectors are placed on the film plane of several types of particle, x-ray and visible spectrometers or directly in the path of the emissions to be measured and the output is imaged by a visible streak camera. Time and spatial dependence of the emission from plasmas generated from a single pulse of electromagnetic radiation or from a single particle beam burst can be recorded.

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

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  8. Experimental observation of the ion energy spectra of Al, Co, and Cu laser produced plasmas

    NASA Astrophysics Data System (ADS)

    Apianiz, Jon Imanol; Peralta Conde, Alvaro; Martnez Perez de Mendiola, Roberto

    2015-12-01

    It is well known that nanosecond laser produced plasmas (LPPs) produce high kinetic energy ions when they expand to vacuum. The acceleration process is nowadays accepted to be due to the formation of a sharp double layer (DL) in the plasma-vacuum boundary. With the purpose of studying this acceleration process, kinetic energy spectra of the plasma ions are measured for each charge state separately. Experimental results are obtained by irradiating planar targets of Cu, Co and Al at a laser wavelength of 532 nm and fluences up to 58.1 J cm-2. The obtained results show two new insights in the ion energy spectra. Firstly, they are non-maxwellian despite the widely accepted local thermal equilibrium in these type of plasmas. Secondly they show non-expected bicomponents distributions. The average energy of each species does not vary linearly with the charge state, suggesting complex acceleration processes.

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

    SciTech Connect

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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    1993-02-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  12. Measurement of Noise Produced by a Plasma Contactor Operating in Ground Based Facilities

    NASA Technical Reports Server (NTRS)

    Snyder, Steve

    1996-01-01

    Methods to measure electric field fluctuations accurately in a plasma with an active monopole antenna are described. It is shown that the conductive surfaces of the antenna must be adequately isolated from the ambient plasma and that the monopole must be sufficiently short to avoid antenna amplifier saturation. Experimental results illustrate that the noise produced by plasma contactor operation and sensed by the antenna is due to plasma phenomena and is not induced by laboratory power supplies. A good correlation is shown between the current fluctuations in the contactor electrical circuit and the noise detected by the antenna. A large body of experimental data support the conclusion that the majority of noise sensed by the antenna at frequencies less than 1 MHz is due to current fluctuations (electrostatic waves) in the plasma adjacent to the antenna and not to electromagnetic wave radiation. Caution is suggested when comparing antenna noise measurements to conventional specifications for radiated emissions.

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

    NASA Astrophysics Data System (ADS)

    Torrisi, L.

    2013-12-01

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

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

    NASA Technical Reports Server (NTRS)

    Kintner, P. M.; Kelley, M.

    1982-01-01

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

  15. Photo-oxidation of Polymers Synthesized by Plasma and Initiated CVD

    DOE PAGESBeta

    Baxamusa, Salmaan H.; Suresh, Aravind; Ehrmann, Paul; Laurence, Ted; Hanania, Jiries; Hayes, Jeff; Harley, Stephen; Burkey, Daniel D.

    2015-11-09

    Plasma polymers are often limited by their susceptibility to spontaneous and photo-oxidation. We show that the unusual photoluminescence (PL) behavior of a plasma polymer of trans-2-butene is correlated with its photoluminescence strength. These photo-processes occur under blue light illumination (λ=405 nm), distinguishing them from traditional ultraviolet degradation of polymers. These photo-active defects are likely formed during the plasma deposition process and we show that a polymer synthesized using initiated (i)CVD, non-plasma method, has 1000× lower PL signal and enhanced photo-stability. In conclusion, non-plasma methods such as iCVD may therefore be a route to overcoming material aging issues that limit themore » adoption of plasma polymers.« less

  16. Photo-oxidation of Polymers Synthesized by Plasma and Initiated CVD

    SciTech Connect

    Baxamusa, Salmaan H.; Suresh, Aravind; Ehrmann, Paul; Laurence, Ted; Hanania, Jiries; Hayes, Jeff; Harley, Stephen; Burkey, Daniel D.

    2015-11-09

    Plasma polymers are often limited by their susceptibility to spontaneous and photo-oxidation. We show that the unusual photoluminescence (PL) behavior of a plasma polymer of trans-2-butene is correlated with its photoluminescence strength. These photo-processes occur under blue light illumination (λ=405 nm), distinguishing them from traditional ultraviolet degradation of polymers. These photo-active defects are likely formed during the plasma deposition process and we show that a polymer synthesized using initiated (i)CVD, non-plasma method, has 1000× lower PL signal and enhanced photo-stability. In conclusion, non-plasma methods such as iCVD may therefore be a route to overcoming material aging issues that limit the adoption of plasma polymers.

  17. Axial distribution of a VHF H2 plasma produced by a narrow gap discharge

    NASA Astrophysics Data System (ADS)

    Chen, Kuan-Chen; Chen, Chia-Fu; Lien, Cheng-Yang; Chiu, Kuo-Feng; Shi, Jen-Bin; Tsai, Yu-Jer; Lien, Ting-Kuei; Ogiwara, Kohei; Uchino, Kiichiro; Kawai, Yoshinobu

    2016-01-01

    A capacitively coupled VHF H2 plasma was produced with a conventional parallel plate electrode of 400 300 mm2. Axial distributions of the plasma parameters were examined using a movable Langmuir probe. The electron density had a hill-like profile near the center while the electron temperature around the discharge electrode was higher than that near the center. It was found that the axial distribution of the plasma potential was considerably different from that based on ohmic heating. The measured sheath potentials around the discharge electrode were lower than the theoretical potentials. A simulation using a hybrid model was performed and compared the results with the experimental results.

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

    NASA Astrophysics Data System (ADS)

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

    1996-04-01

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

  19. Chargel species analysis as a diagnostic tool for laser produced plasma characterization

    NASA Astrophysics Data System (ADS)

    Amoruso, S.; Armenante, M.; Berardi, V.; Bruzzese, R.; Pica, G.; Velotta, R.

    1996-10-01

    In this work we report on a study of the plasma produced by UV ( ? = 351 nm) laser ablation of an aluminum target. In particular, we have directly measured the flux velocity of ablated ions along the normal to the metal target, the corresponding ion temperature, and the average kinetic energy by using an electrostatic energy analyzer. Moreover, by interpreting the measured ion energy distributions within the framework of the hydrodynamical model, we have also inferred an estimate of plasma electron density and temperature, which provide significant information on the laser plasma characterization in a number of applications.

  20. Radiation produced by femtosecond laser-plasma interaction during dielectric breakdown.

    PubMed

    Carr, C W; Feit, M D; Rubenchik, A M; De Mange, P; Kucheyev, S O; Shirk, M D; Radousky, H B; Demos, S G

    2005-03-15

    Optical breakdown by femtosecond and nanosecond laser pulses in transparent dielectrics produces an ionized region of dense plasma confined within the bulk of the material. This ionized region is responsible for broadband radiation that accompanies the breakdown process. Spectroscopic measurements of the accompanying light have been used to show that, depending on the laser parameters, the spectra may originate from plasma-induced second-harmonic generation, supercontinuum generation, or thermal emission by the plasma. By monitoring the emission from the ionized region, one can ascertain the predominant breakdown mechanism and the morphology of the damage region. PMID:15792009

  1. The impact of Hall physics on magnetized plasma jets produced by radial foil configurations

    NASA Astrophysics Data System (ADS)

    Gourdain, P.-A.; Greenly, J. B.; Hammer, D. A.; Kusse, B. R.; Schrafel, P. C.; Seyler, C. E.; Bland, S. N.; Hall, G. N.; Lebedev, S. V.; Suzuki-Vidal, F.

    2012-10-01

    Although no one argues that plasma resistivity is important to include in the astrophysical simulations, based upon experiments with magnetized jets on pulsed power machines in the laboratory, we believe it may also be important to include the Hall term in the generalized Ohm's law in astrophysics simulation codes. In this talk, experiments carried out at Cornell University and at Imperial College on 1 to 1.5 MA pulsed power generators feature a plasma disk and a collimated, axial plasma jet with large Re (10^5) and Rem (10^3). The plasma jet is generated by ablation from electrical currents, which flow in a thin aluminum foil and converge to a central multi-pin cathode located under the foil. A twist in the pins produce the axial magnetic field necessary to magnetized the jet. It was observed that changing the polarity of the current alters drastically the plasma dynamics, an indication of the importance of the Hall effect in plasmas produced by radial foils. The overall agreement between experimental results and numerical simulations indicates that PERSEUS accounts properly for Hall physics in this geometry and plasma parameter range. Scaling to astrophysical occurrences via numerical simulations should highlight how Hall physics affects the dynamics of larger accretion disks.

  2. Initial Experiments with the Plasma Chambers Mago, Having no Central Current-Carrying POST in the Plasma Heating Compartment

    NASA Astrophysics Data System (ADS)

    Bazanov, A. A.; Pozdov, N. I.

    2004-11-01

    In all the experiments performed to date, the MAGO chambers had a central current-carrying post used for the introduction of the initial magnetic field into the chamber. The results of the first experiments on the capacitor bank facility CASCADE in which the initial magnetic field was not introduced into MAGO chamber, and the central current-carrying post was removed from the plasma heating compartment, are presented in the report. The experiments demonstrated the feasibility of obtaining high-temperature plasma in such chambers with neutron emission duration of 1-1.5 μs. The results may be very useful analyzing the mechanisms of the plasma preliminary heating in MAGO chambers and for testing the applied calculation techniques.

  3. Convection of Plasmaspheric Plasma into the Outer Magnetosphere and Boundary Layer Region: Initial Results

    NASA Technical Reports Server (NTRS)

    Ober, Daniel M.; Horwitz, J. L.

    1998-01-01

    We present initial results on the modeling of the circulation of plasmaspheric-origin plasma into the outer magnetosphere and low-latitude boundary layer (LLBL), using a dynamic global core plasma model (DGCPM). The DGCPM includes the influences of spatially and temporally varying convection and refilling processes to calculate the equatorial core plasma density distribution throughout the magnetosphere. We have developed an initial description of the electric and magnetic field structures in the outer magnetosphere region. The purpose of this paper is to examine both the losses of plasmaspheric-origin plasma into the magnetopause boundary layer and the convection of this plasma that remains trapped on closed magnetic field lines. For the LLBL electric and magnetic structures we have adopted here, the plasmaspheric plasma reaching the outer magnetosphere is diverted anti-sunward primarily along the dusk flank. These plasmas reach X= -15 R(sub E) in the LLBL approximately 3.2 hours after the initial enhancement of convection and continues to populate the LLBL for 12 hours as the convection electric field diminishes.

  4. Convection of Plasmaspheric Plasma into the Outer Magnetosphere and Boundary Layer Region: Initial Results

    NASA Technical Reports Server (NTRS)

    Ober, Daniel M.; Horwitz, J. L.; Gallagher, D. L.

    1998-01-01

    We present initial results on the modeling of the circulation of plasmaspheric- origin plasma into the outer magnetosphere and low-latitude boundary layer (LLBL), using a dynamic global core plasma model (DGCPM). The DGCPM includes the influences of spatially and temporally varying convection and refilling processes to calculate the equatorial core plasma density distribution throughout the magnetosphere. We have developed an initial description of the electric and magnetic field structures in the outer magnetosphere region. The purpose of this paper is to examine both the losses of plasmaspheric-origin plasma into the magnetopause boundary layer and the convection of this plasma that remains trapped on closed magnetic field lines. For the LLBL electric and magnetic structures we have adopted here, the plasmaspheric plasma reaching the outer magnetosphere is diverted anti-sunward primarily along the dusk flank. These plasmas reach X = -15 R(sub E) in the LLBL approximately 3.2 hours after the initial enhancement of convection and continues to populate the LLBL for 12 hours as the convection electric field diminishes.

  5. Electron density measurements using high-order harmonic generation in laser-produced plasmas

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

    We demonstrate the method of the measurements of electron density in the low-dense, low-ionized laser-produced plasma using the nonlinear optical process of high-order harmonic generation of ultrashort pulses at the conditions of the quasi-phase-matching of driving and harmonic waves. Electron density was defined using the relations of quasi-phase-matching. We show the results of our measurements of electron density in the range of 1016-1017 cm-3 using the multi-jet silver plasma produced for the harmonic generation.

  6. Electron density measurements using high-order harmonic generation in laser-produced plasmas

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    We demonstrate the method of the measurements of electron density in the low-dense, low-ionized laser-produced plasma using the nonlinear optical process of high-order harmonic generation of ultrashort pulses at the conditions of the quasi-phase-matching of driving and harmonic waves. Electron density was defined using the relations of quasi-phase-matching. We show the results of our measurements of electron density in the range of 1016-1017 cm-3 using the multi-jet silver plasma produced for the harmonic generation.

  7. Spectroscopic study using line ratios of lithiumlike ions in a laser-produced plasma

    SciTech Connect

    Moreno, J.C.; Goldsmith, S.; Griem, H.R.

    1989-02-15

    Spectra of highly ionized titanium and calcium in the extreme ultraviolet region were observed in laser-produced plasmas using the OMEGA 24 beam (351 nm) laser system at the University of Rochester. The plasmas were produced using glass microballoon targets coated with a layer of a medium Z element and a layer of parylene (CH). Time-integrated electron temperatures and densities were obtained by comparing measured line intensity ratios of lithiumlike charge states of Ti and Ca to numerical calculations from a collisional-radiative model. The variation of line intensity ratios with electron density and temperature using the collisional-radiative model is discussed.

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

    DOEpatents

    Augustoni, A.L.; Gerardo, J.B.; Raymond, T.D.

    1992-12-29

    Method and apparatus for generating x-rays for use in, for instance, x-ray photolithography is disclosed. The method of generating x-rays includes the steps of providing a target and irradiating the target with a laser system which produces a train of sub-pulses to generate an x-ray producing plasma. The sub-pulses are of both high intensity and short duration. The apparatus for generating x-rays from a plasma includes a vacuum chamber, a target supported within the chamber and a laser system, including a short storage time laser. 8 figs.

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

    DOEpatents

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

    1992-01-01

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

  10. Density, temperature and size of a plasma produced in single and double shell liner implosions

    NASA Astrophysics Data System (ADS)

    Chaikovsky, S. A.; Sorokin, S. A.

    1997-05-01

    Single and double shell plasma liner implosion experiments have been performed on the SNOP-3 pulsed generator (Imax?1 MA, ??80 ns). The plasma density and temperature were determined with a technique involving collisional radiative equilibrium calculations and measurements of the K-shell radiation power, the K-shell radiating plasma size, and the He-? to Ly-? line ratio. The resonance-to-intercombination and resonance-to-satellite line ratios were also used to determine the plasma density and the temperature, respectively. It is shown in the paper, that all the mass of the inner shell of the double shell liner is assembled into a tight pinch and high radial compressions (?45) of the inner shell occur at the appropriate inner shell initial radius.

  11. Steady-state hot-ion plasma produced by crossed electric and magnetic fields

    NASA Technical Reports Server (NTRS)

    Sigman, D. R.; Reinmann, J. J.

    1973-01-01

    Results of initial diagnostics on the Lewis Research Center hot-ion-plasma source (HIP-1) are reported. The mirror-contained plasma was heated by applying a radial electric field similar to that used in the ORNL burnout experiments. An electrostatic neutral particle analyzer was used to make a parametric study of ion energy distributions in both hydrogen and euterium plasmas. Ion temperatures as high as 2 keV were measured in plasmas with electron densities greater than 10 to 12th power/cu cm. The performance of the device was found to be extremely sensitive to a magnetic field. There are indications that ion heating was reduced when the size of the Larmor orbit was larger than the region of a strong radial electric field.

  12. Impact of cranberry juice on initial adhesion of the EPS producing bacterium Burkholderia cepacia.

    PubMed

    Yang, Xuejiao; Teng, Fucheng; Zeng, Hongbo; Liu, Yang

    2012-01-01

    The impact of cranberry juice was investigated with respect to the initial adhesion of three isogenic strains of the bacterium Burkholderia cepacia with different extracellular polymeric substance (EPS) producing capacities, viz. a wild-type cepacian EPS producer PC184 and its mutant strains PC184rml with reduced EPS production and PC184bceK with a deficiency in EPS production. Adhesion experiments conducted in a parallel-plate flow chamber demonstrated that, in the absence of cranberry juice, strain PC184 had a significantly higher adhesive capacity compared to the mutant strains. In the presence of cranberry juice, the adhesive capacity of the EPS-producing strain PC184 was largely reduced, while cranberry juice had little impact on the adhesion behavior of either mutant strain. Thermodynamic modeling supported the results from adhesion experiments. Surface force apparatus (SFA) and scanning electron microscope (SEM) studies demonstrated a strong association between cranberry juice components and bacterial EPS. It was concluded that cranberry juice components could impact bacterial initial adhesion by adhering to the EPS and impairing the adhesive capacity of the cells, which provides an insight into the development of novel treatment strategies to block the biofilm formation associated with bacterial infection. PMID:22554250

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

    NASA Astrophysics Data System (ADS)

    Sarafopoulos, D. V.

    2008-06-01

    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 missing, that might help explain the persistent, outstanding deficiencies in our physical description of magnetospheric substorms. The mechanism is tested, checked, and found consistent with substorm associated observations performed ~30 and 60 RE away from Earth.

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

    SciTech Connect

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

    2015-03-15

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

  15. Quasi-steady-state air plasma channel produced by a femtosecond laser pulse sequence

    PubMed Central

    Lu, Xin; Chen, Shi-You; Ma, Jing-Long; Hou, Lei; Liao, Guo-Qian; Wang, Jin-Guang; Han, Yu-Jing; Liu, Xiao-Long; Teng, Hao; Han, Hai-Nian; Li, Yu-Tong; Chen, Li-Ming; Wei, Zhi-Yi; Zhang, Jie

    2015-01-01

    A long air plasma channel can be formed by filamentation of intense femtosecond laser pulses. However, the lifetime of the plasma channel produced by a single femtosecond laser pulse is too short (only a few nanoseconds) for many potential applications based on the conductivity of the plasma channel. Therefore, prolonging the lifetime of the plasma channel is one of the key challenges in the research of femtosecond laser filamentation. In this study, a unique femtosecond laser source was developed to produce a high-quality femtosecond laser pulse sequence with an interval of 2.9 ns and a uniformly distributed single-pulse energy. The metre scale quasi-steady-state plasma channel with a 60–80 ns lifetime was formed by such pulse sequences in air. The simulation study for filamentation of dual femtosecond pulses indicated that the plasma channel left by the previous pulse was weakly affected the filamentation of the next pulse in sequence under our experimental conditions. PMID:26493279

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  17. Mixing layer produced by a screen and its dependence on initial conditions

    NASA Astrophysics Data System (ADS)

    Oguchi, H.; Inoue, O.

    1984-05-01

    Attention is given to dependence on initial disturbances in an attempt to elucidate the structure of turbulent mixing layers produced by setting a woven wire screen perpendicular to the freestream in a wind tunnel test section in order to obstruct part of the flow. Three kinds of model geometry screens yielded mixing layers that can be regarded as the equivalents of the plane mixing layer, and of two-dimensional and axisymmetric wakes, issuing into ambient streams of higher velocity. Flow features are visualized by the smoke-wire method, and statistical quantities are measured by a laser-Doppler velocimeter. Large scale transverse vortices persist in all cases. The mixing layers are in self-preserving state up to at least the third-order moments, but the self-preserving state is different in each case. Mixing layer growth rates strongly depend on the disturbance initially imposed.

  18. Correlated-intensity velocimeter for arbitrary reflector for laser-produced plasma experiments

    SciTech Connect

    Wang Zhehui; Luo Shengnian; Barnes, Cris W.; Briggs, Matthew E.; Paisley, Dennis L.; Paul, Stephen F.

    2006-10-15

    A laser-based technique, called correlated-intensity velocimeter for arbitrary reflector (CIVAR), is described for velocity measurement of reflecting surfaces in real time. Velocity versus time is an important measurement in laser-produced high-energy density plasma experiments because the motion of the surface depends on both the equation of the state of the surface material and laser-produced plasma. The physics and working principle of CIVAR are the same as those of a previous concept that resolves Doppler shift of plasma light emission using a pair of narrow passband interference filters. One unique feature of CIVAR is that a reflected laser beam is used instead of plasma emission. Therefore, CIVAR is applicable to both emitting and nonemitting reflecting surfaces. Other advantages of CIVAR include its simplicity, lower cost, and unambiguous data analysis that can be fully automated. The design of a single-point CIVAR is described in detail with emphasis on laser wavelength selection and signal-to-noise ratio. The single-point CIVAR system can be expanded into a multiple-point system straightforwardly. It is possible to use CIVAR concept to construct a two-dimensional imaging system for a nonuniform velocity field of a large reflecting surface; such a velocity imaging system may have applications beyond laser-produced plasma experiments, for example, in shock compression of condensed matter.

  19. Effect of Atmospheric Plasma Treatment to Titanium Surface on Initial Osteoblast-Like Cell Spreading. .

    PubMed

    Kim, In-Hye; Son, Jun-Sik; Kwon, Tae-Yub; Kim, Kyo-Han

    2015-01-01

    Plasma treatments are becoming a popular method for modifying the characteristics of a range of substrate surfaces. Atmospheric pressure plasma is cost-efficient, safe and simple compared to high-pressure plasma. This study examined the effects of atmospheric pressure plasma to a titanium (Ti) surface on osteoblast-like cell (osteoblast) spreading and cellular networks. The characteristics of the Ti surface before and after the atmospheric plasma treatment were analyzed by X-ray photoemission spectroscopy (XPS), scanning electron microscopy (SEM), contact angle measurements, and an optical 3D profiling system. The morphology of osteoblasts attached to the Ti surfaces was observed by SEM and confocal laser scanning microscopy. The atmospheric pressure plasma made the Ti surfaces more hydrophilic. The osteoblasts that adhered to the untreated surface were round and spherical, whereas the cells covered a larger surface area on the plasma-treated surface. The plasma-treated Ti surface showed enhanced cell spreading and migration with more developed cellular networks. In conclusion, an atmospheric plasma treatment is a potential surface modifying method that can enhance the initial the cell affinity at the early stages in vitro. PMID:26328317

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

    SciTech Connect

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

    2015-04-15

    Novel experiments to study the strongly-driven collision of parallel magnetic fields in ????10, laser-produced plasmas have been conducted using monoenergetic proton radiography. These experiments were designed to probe the process of magnetic flux pileup, which has been identified in prior laser-plasma experiments as a key physical mechanism in the reconnection of anti-parallel magnetic fields when the reconnection inflow is dominated by strong plasma flows. In the present experiments using colliding plasmas carrying parallel magnetic fields, the magnetic flux is found to be conserved and slightly compressed in the collision region. Two-dimensional (2D) particle-in-cell 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.

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

    SciTech Connect

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

    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. Apoptotic effects on cultured cells of atmospheric-pressure plasma produced using various gases

    NASA Astrophysics Data System (ADS)

    Tominami, Kanako; Kanetaka, Hiroyasu; Kudo, Tada-aki; Sasaki, Shota; Kaneko, Toshiro

    2016-01-01

    This study investigated the effects of low-temperature atmospheric-pressure plasma on various cells such as rat fibroblastic Rat-1 cell line, rat neuroblastoma-like PC12 cell line, and rat macrophage-like NR8383 cell line. The plasma was irradiated directly to a culture medium containing plated cells for 0–20 s. The applied voltage, excitation frequency, and argon or helium gas flow were, respectively, 3–6 kV, 10 kHz, and 3 L/min. Cell viability and apoptotic activity were evaluated using annexin-V/propidium iodide staining. Results showed that the low-temperature atmospheric-pressure plasma irradiation promoted cell death in a discharge-voltage-dependent and irradiation-time-dependent manner. Furthermore, different effects are produced depending on the cell type. Moreover, entirely different mechanisms might be responsible for the induction of apoptosis in cells by helium and argon plasma.

  3. Numerical simulations of charge state distribution from a KrF laser-produced plasma

    SciTech Connect

    Tsui, Y.Y.; Fedosejevs, R.; Offenberger, A.A.; Rankin, R.; Capjack, C.E. )

    1993-11-01

    A calculation of the charge state distribution of the asymptotic evolution of a plasma produced by an ultraviolet laser has been carried out by coupling the results of a detailed two-dimensional hydrodynamic simulation of the creation and heating of the plasma to a simpler one-dimensional hydrodynamic code. The latter incorporates time-dependent ionization and recombination physics and is used to model the subsequent expansion and cooling of the plasma. The simulation results are compared to experimental charge state distributions obtained by using a single shot electrodynamic charge analyzer. The sensitivity of the results to the rate coefficients used for the recombination calculations was tested and the calculated distributions were found to be most sensitive to the values of the three-body recombination rate and the amount of heat returned to the plasma. Reasonable agreement was found between the measured and calculated charge state distributions.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    Angular-resolved ion time-of-flight spectra as well as extreme ultraviolet radiation in laser-produced tin droplet plasma are investigated experimentally and theoretically. Tin droplets with a diameter of 150 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.

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

    SciTech Connect

    Coons, R. W.; Harilal, S. S.; Campos, D.; Hassanein, A.

    2010-09-15

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

  6. Diagnostics of beam plasma produced in dielectric cavity at fore-vacuum pressures

    NASA Astrophysics Data System (ADS)

    Zolotukhin, D.

    2016-01-01

    The results of the probe and optical measurements of plasma parameters produced during the injection of the electron beam with the energy of 3-8 keV and current of 30-60 mA into a dielectric cavity at the argon pressure of 2-12 Pa are presented. The possibility of continuous injection of the electron beam into the cavity without current-collecting electrodes inside is demonstrated. The axial distribution of the values of the plasma parameters (density, electron temperature and floating potential) in the cavity is discussed. The plasma concentration in the cavity is shown to be approximately 20% higher, and the electron temperature 1.5-2 times higher, than in the case of generating the plasma in the free space of the vacuum chamber.

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

    SciTech Connect

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

    2015-04-08

    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 (PIC) simulations predict a stronger flux compression and amplification of the magnetic field strength, and this discrepancy is attributed to the three-dimensional (3D) collision geometry. Future experiments may drive a stronger collision and further explore flux pileup in the context of the strongly-driven interaction of magnetic fields.

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

    SciTech Connect

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

    2015-04-01

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

  9. Cutting Tools Nitriding in Plasma Produced by a Fast Neutral Molecule Beam

    NASA Astrophysics Data System (ADS)

    Metel, Alexander; Grigoriev, Sergei; Melnik, Yury; Panin, Vitaly; Prudnikov, Vladimir

    2011-08-01

    Nitrogen plasma produced by a broad beam of fast neutral nitrogen molecules in 0.12-m3 vacuum chamber has been studied and used for cutting tools nitriding. The study results prove that fast molecules play a leading role in gas ionization and plasma density is proportional to their energy, equivalent current and gas pressure. Plasma is quite nonuniform: its density is maximal within the beam and rapidly decreases beyond it. Non-self-sustained glow discharge between chamber and an anode immersed in the plasma reduces plasma nonuniformity down to 10%, when discharge voltage amounts to 200-300 V, and raises plasma density by an order of magnitude. After 1-h-long soaking in discharge plasma of isolated from the chamber and heated by 4-keV beam up to 500 C cutting plates made of high-speed steel their microhardness rises from 950 up to 1400 HV, and the mean radius of cutting edges decreases from 20 to 18 m.

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

    SciTech Connect

    Gupta, G.P.; Sinha, B.K.

    1996-10-01

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

  11. Initial results from the ISEE-1 and -2 plasma wave investigation. [magnetospheric survey

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    A survey of initial results from the plasma-wave investigation on the ISEE 1 and 2 spacecraft is presented. The plasma-wave instruments employed are designed to provide measurements of the electric and magnetic fields of plasma waves over the frequency range from about 5 Hz to 300 kHz. Several representative satellite passes are analyzed in detail and discussed. The results considered are shown to demonstrate the very high-quality data being obtained with the instruments and to illustrate the wide range of magnetospheric plasma-physics problems that can be treated with the ISEE spacecraft. Comparisons of plasma-wave spectra between the two spacecraft are performed which indicate the great advantages of using two spacecraft in similar orbits to unravel the complex spatial and temporal variations that occur in the magnetosphere.

  12. XUV spectral analysis of ns- and ps-laser produced platinum plasmas

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    XUV spectra of ns- and ps-laser produced platinum (Pt) plasmas in the 1–7 nm wavelength region, where Δn = 1 n = 4–5 and Δn = 0 n = 4-4 transitions dominate the observed emission, were investigated experimentally and theoretically. Ab initio calculations using the Hartree–Fock with configuration interaction (HFCI) Cowan suite of codes and the unresolved transition array (UTA) formalism, as well as consideration of previous predictions of isoelectronic trends, together with spectra obtained under different laser power densities are all employed to identify lines and a number of new features in spectra from Pt XX to Pt XLII. The possible reasons for the main differences between the ns- and ps-laser plasmas spectra are also demonstrated. This work extends previous analyses of the XUV spectra of laser produced gold, tungsten, tantalum, hafnium and rhenium plasmas in the 1–7 nm wavelength range.

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

    SciTech Connect

    Eliasson, B.

    2014-02-15

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

  14. Similarity of Skeletal Structures Observed in Laser-Produced Plasmas and High-Current Electric Discharges

    NASA Astrophysics Data System (ADS)

    Rantsev-Kartinov, V. A.; Kukushkin, A. B.

    2001-10-01

    The paper reports on the presence of skeletal structures in the filtered x-ray pinhole images of plasma corona produced in former experiments [1] on irradiating the foils by a pulsed laser beam. These structures are shown to be similar to tubular and cartwheel-like structures previously found [2] in the visible light images of the plasma in various fusion plasmas (Z-pinch, plasma focus, tokamak). Such topological identity allows to draw a parallel between laser-produced plasmas and electric breakdown stage of various high-current electric discharges. This allows, in turn, to extend to the case of laser-produced plasmas some points of the hypothesis [3] which suggested the probable necessity to go beyond the frame of classical electrodynamics in describing the long-range (macroscopic) correlations/bonds in a broad range of plasmas. REFERENCES [1] Bolshov L.A., et. al., Sov. Phys. JETP 65 (1987) 1160; Burdonskii I.N., et. al., Laser and Part. Beams, 6(2) (1988) 327. [2] Kukushkin A.B., Rantsev-Kartinov V.A., Proc. 27-th EPS PPCF (2000) p2-029 p2-028 p2-051. [3] Kukushkin A.B., Rantsev-Kartinov V.A., Fusion Energy 1998 (IAEA, Vienna, 1999, IAEA-CSP-1/P, Vol. 3) p.1131; Proc. 26-th EPS PPCF (1999) p2-087.

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

    SciTech Connect

    Castano-Giraldo, C.; Aghazarian, Maro; Caughman, John B; Ruzic, D. N.

    2012-01-01

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

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

    SciTech Connect

    Heidrich, J. E.

    1981-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Xu, Yan; Wu, SiZhong; Zheng, WuDi

    2015-04-01

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

  18. Towards laboratory-produced relativistic electron-positron pair-plasmas

    SciTech Connect

    Chen, H; Wilks, S C; Meyerhofer, D D; Beiersdorfer, P; Cauble, R; Dollar, F; Falk, K; Hazi, A; Murphy, C D; Park, J; Seely, J; Szabo, C I; Shepherd, R; Tommasini, R; Zulick, K

    2010-08-31

    Relativistic pair-plasmas and jets are believed to exist in many astrophysical objects and are often invoked to explain energetic phenomena related to Gamma Ray Bursts and Black Holes. On earth, positrons from radioactive isotopes or accelerators are used extensively at low energies (sub-MeV) in areas related to surface science positron emission tomography and basic antimatter science. Experimental platforms capable of producing the high-temperature pair-plasma and high-flux jets required to simulate astrophysical positron conditions have so far been absent. In the last few years, we performed extensive experiments generating positrons with intense lasers where we found that relativistic electron and positron jets are produced by irradiating a solid gold target with an intense picosecond laser pulse. The positron temperatures in directions parallel and transverse to the beam both exceeded 0.5 MeV, and the density of electrons and positrons in these jets are of order 10{sup 16} cm{sup -3} and 10{sup 13} cm{sup -3}, respectively. With the advent of high-energy ultra-short laser pulses, we expect that a charge-neutral, relativistic pair-plasma is achievable, a novel regime of laboratory-produced hot dense matter. This talk will present some details of the laser-produced pair-plasma experiments.

  19. Shockwaves and filaments induced by counter-streaming laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Yuan, D. W.; Li, Y. T.; Liu, X.; Zhang, Y.; Zhong, J. Y.; Zheng, W. D.; Dong, Q. L.; Chen, M.; Sakawa, Y.; Morita, T.; Kuramitsu, Y.; Kato, T. N.; Takabe, H.; Rhee, Yong-Joo; Zhu, J. Q.; Zhao, G.; Zhang, J.

    2013-06-01

    The interaction between two counter-streaming laser-produced plasmas is studied with shadowgraph and interferometry on the Shenguang II (SG-II) laser facility. Shockwaves and filaments are observed at different timing. The simulation and theoretical analysis indicate that these structures are probably induced by collisionless mechanisms.

  20. Collisionless shockwaves formed by counter-streaming laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Liu, X.; Li, Y. T.; Zhang, Y.; Zhong, J. Y.; Zheng, W. D.; Dong, Q. L.; Chen, M.; Zhao, G.; Sakawa, Y.; Morita, T.; Kuramitsu, Y.; Kato, T. N.; Chen, L. M.; Lu, X.; Ma, J. L.; Wang, W. M.; Sheng, Z. M.; Takabe, H.; Rhee, Y.-J.; Ding, Y. K.; Jiang, S. E.; Liu, S. Y.; Zhu, J. Q.; Zhang, J.

    2011-09-01

    The interaction between two counter-streaming laser-produced plasmas is investigated using the high-power Shenguang II laser facility. The shockwaves observed in our experiment are believed to be excited by collisionless mechanisms. The dimensionless parameters calculated with the results suggest that it is possible to scale the observation to the supernova remnants using transformation and similarity criteria.

  1. Plasma-chemical method for producing metal oxide powders and their application

    NASA Astrophysics Data System (ADS)

    Zhukov, I.; Vorozhtsov, S.; Promakhov, V.; Bondarchuk, I.; Zhukov, A.; Vorozhtsov, A.

    2015-11-01

    Structure and properties of ZrO2 and Al2O3 powders produced using plasma chemical technique were studied in the framework of this research. Obtained Al2O3 powder was used for reinforcement of Al alloy. Improvement of mechanical properties of Al alloy associated with introduction of alumina particles into the melt was demonstrated.

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

    SciTech Connect

    Xu, Yan; Wu, SiZhong; Zheng, WuDi

    2015-04-15

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

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

    SciTech Connect

    Afonin, V. I.

    2009-02-15

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

  4. A NEW CLASS OF THIN FILM HYDROGELS PRODUCED BY PLASMA POLYMERIZATION.

    PubMed

    Bhattacharyya, Dhiman; Pillai, Karthikeyan; Chyan, Oliver M R; Tang, Liping; Timmons, Richard B

    2007-05-01

    A simple, direct route to preparation of surface immobilized hydrogel films is described. Specifically, low pressure RF pulsed plasma polymerization of 1-amino-2-propanol and 2-(ethylamino)ethanol monomers produced thin hydrogel films deposited on substrates located in the plasma reactor. The successful syntheses were carried out under plasma conditions which not only yield the hydrogel but are also sufficiently energetic to produce films strongly grafted to the substrates. The polymer films obtained exhibit the thermoresponsive property of hydrogels, as shown by film color change with temperature. Additional evidence for the phase transition properties of these films was obtained using water contact angle and capillary rise measurements. The plasma polymerization approach provides an unusually simple route to synthesis of hydrogels in which the films are pin-hole free and are of easily controlled thickness. An important added advantage, particularly for applications involving biomaterials, is the conformal property of the plasma generated polymer films. The results obtained suggest that this approach should be applicable to a variety of other monomers and, based on differences observed with the present two monomers, suggest synthesis of films which exhibit a range of phase transition temperatures. PMID:19079730

  5. Novel approach to produce polymerized hydrocarbon coatings using dielectric barrier controlled atmospheric pressure glow discharge plasma

    NASA Astrophysics Data System (ADS)

    Mishra, K. K.; Khardekar, R. K.; Singh, Rashmi; Pant, H. C.

    2002-09-01

    Conventionally, low-pressure (<1 Torr) electrical discharges are used for material processing and thin-film deposition. These schemes suffer mainly due to the high cost of equipment and the complexity of operations. The atmospheric pressure glow discharge plasma is developed using a threaded styled electrode in different configurations, and these reactors are used to produce plasma polymerized coatings, required on plane substrates as self-supporting films to obtain membranes for blocking holes in cavities, and on microballoon targets, which are used as fuel containers for inertial confinement fusion, to avoid DT gas permeation. Helium gas is used as the supporting gas for formation and stabilization of atmospheric pressure glow discharge plasma reactors. Ethylene and acetylene gases are used as monomers to produce plasma polymerized hydrocarbon films. These films are characterized using scanning electron microscopy. Plasma polymerized coatings of thickness 100 nm-10 μm with a smooth surface finish (rms<100 nm) are deposited successfully. The surface finish is further improved using a postdischarge configuration. Preliminary results are very encouraging but further progress is to be made in this area. We are also planning to extend this technique for C:H coating of microballoons, which are used as fuel containers in inertial confinement fusion.

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

    SciTech Connect

    White, Terry L.; Paulauskas, Felix L.; Bigelow, Timothy S.

    2010-11-02

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

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

    DOEpatents

    Kong, Peter C.; Detering, Brent A.

    2004-10-19

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

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

    DOEpatents

    Kong, Peter C.; Detering, Brent A.

    2003-08-19

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

  9. Studies of Population Inversions in the Soft X - Spectral Region in Carbon Dioxide Laser Produced Plasmas.

    NASA Astrophysics Data System (ADS)

    Keane, Christopher John

    The recombination approach for development of a short wavelength laser is one of two schemes used in recent demonstrations of high gain in the soft X-ray region. In this work, a theoretical and experimental study of recombination pumped soft X-ray population inversions in Li-like carbon (CIV) and H-like carbon (CVI) in CO(,2) laser produced plasmas is presented. A collisional radiative model is used to examine the behavior of the gain coefficients for various transitions in the C('5+) ion with plasma parameters, and the optimum conditions for gain defined. A general formalism that elucidates the separate roles of radiative power loss and electron cooling in dense transient plasmas is described and used to examine the feasibility of quickly radiatively cooling a dense plasma to bring about optimum conditions for gain in a recombination system. Experimental studies of the effectiveness of radiation cooling in generating recombination pumped soft X-ray population inversions in CIV are carried out in freely expanding CO(,2) laser produced plasmas. Measurements of gain length products as high as 6.5 on the 182 (ANGSTROM) transition in CVI in magnetically confined CO(,2) laser produced plasmas are reviewed and observations of stimulated emission at 182 (ANGSTROM) obtained with an XUV multilayer mirror in use are presented. In both of these experiments, radiation cooling is shown to play a significant role in bringing about the conditions necessary for gain. In addition to this work, results from a preliminary test of a resonant photoexcitation experiment involving AIV pumping FVI are presented.

  10. Characterization of Laser-Produced Plasmas Relevant to Magnetized Collisionless Shocks

    NASA Astrophysics Data System (ADS)

    Schaeffer, D. B.; Bondarenko, A. S.; Everson, E. T.; Clark, S. E.; Constantin, C. G.; Niemann, C.

    2014-10-01

    Recent experiments performed at the University of California, Los Angeles (UCLA) have generated magnetized collisionless shocks driven by a laser-mediated magnetic piston. The effectiveness of the piston at coupling energy between a laser-plasma and an ambient plasma depends highly on the nature of the laser-plasma, which has been hitherto poorly characterized. We present experiments that provide new details on the composition and evolution of laser-produced plasmas relevant to a magnetic piston. Thomson scattering was used to probe the electron temperature and density up to several cm from the target and several microseconds after ablation. Ionization states and blow-off velocities of the ablated plasma were further measured with emission spectroscopy and fast-gate filtered photography. The data compares well to analytic models describing the spatial and temporal temperature and density evolution of the plasma. 1D HELIOS simulations of the laser-target interaction also agree favorably with data that shows fast ions dominated by a single charge state primarily drive the magnetic piston.

  11. Changes in human plasma catecholamines and dopamine-beta-hydroxylase produced by prostaglandin F2 alpha.

    PubMed

    Mueller, R A; Fishburne, J I; Brenner, W E; Braaksma, J T; Staurovsky, L G; Hoffer, J L; Hendricks, C H

    1972-09-01

    Clinical research was conducted into the possible interrelationships between prostaglandin (PG) F2alpha and the human sympathetic nervous system. The study also permitted comparison of the relative sensitivity of 2 indicators of sympatho-adrenal activity: 1) the determination of circulating catecholamines, epinephrine and norepinephrine; and 2) analysis of plasma dopamine-8-hydroxylase activity. Intravenous PGF2alpha infusion was administered to college students 12-18 weeks pregnant to produce abortion; the results were compared to results from nonpregnant controls. Circulating norepinephrine but not plasma epinephrine or dopamine-8-hydroxylase levels were increased in response to the PG. There was no correlation between plasma epinephrine and plasma norepinephrine levels. Plasma dopamine-8-hydroxylase activity was found not to be significantly changed by pregnancy, administration of the analgesic and antiemetic, or the PG infusion. In fact, central venous dopamine-8-hydroxylase activity did not differ significantly from that of arterial blood. The PG did not affect cardiac output or maximal expiratory flow rate. It is suggested that the nausea and diarrhea accompanying PGF2alpha infusion may put stress on the sympathetic nervous activity causing the observed increase in plasma norepinephrine concentration. Since no changes in blood pressure, heart rate, central venous pressure, or cardiac output were observed, it is unlikely that PGF2alpha causes even slight impairment of sympathetic nervous system activity. PMID:4653736

  12. The study of laser plasma plume radiation produced by laser ablation of silicon

    NASA Astrophysics Data System (ADS)

    Huang, Qingju

    2014-12-01

    In order to study the laser plasma plume radiation mechanisms induced by the interaction between Nd: YAG plused laser and silicon, the radiation model of silicon laser plasma plume is established. Laser plasma plume radiation includes atom characteristic lines, ion lines and continuous background. It can reflect the characteristics of laser plasma plume radiation, reveal the mechanism of laser ablation on silicon. Time-resolved measurment of laser plasma plume radiation produced by pulsed Nd: YAG laser ablation of silicon in different ambient gas is thoroughly studied. The experimental ambient gas are N2 and O2.The pulse width of Nd: YAG plused laser adopted in the experiment is 20ns, the pulse energy is 60mJ, the laser pulsing frequency is 10Hz, and the emitted laser wavelength is 1064nm, The silicon target purity is 99.99%, The target is rotating at a speed of 240r/min. The focusing area of the laser on the Si target has a diameter of around 0.8mm.The pressure of ambient gas is tunable between 13Pa and 101.3kPa in the induced chamber, the number of points used in averaging is 15. The experimental results show that the ambient gas has obvious enhancement effect on the radiation intensity of silicon laser plasma plume. With the increase of the ambient gas pressure, the silicon laser plasma plume radiation intensity will first be increased and then be decreased, and the ambient gas has an obvious compression effect on the scope of silicon laser plasma plume radiation. For the two different ambient gases, the maximum silicon laser plasma plume radiation intensity and maximum pressure for they are different, for oxygen at 35kPa, for nitrogen at 50kPa. The silicon laser plasma plume radiation intensity in oxygen is bigger than that in nitrogen.The main excition mechanisms of laser plasma plume radiation induced by Nd:YAG plused laser induced silicon is analyzed, The plused laser can makes part molecules in the ambient gas and silicon atoms ionized at the surface of silicon.The main reason for the generation of the silicon laser plasma plume radiation is the excitation radiation by the collision energy transfer between electrons and atoms or ions. The experimental phenomenon that could be explained by the excition model.

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

    NASA Astrophysics Data System (ADS)

    Cummins, Thomas

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

  14. Stark profiles of forbidden and allowed transitions in a dense, laser produced helium plasma.

    NASA Technical Reports Server (NTRS)

    Ya'akobi, B.; George, E. V.; Bekefi, G.; Hawryluk, R. J.

    1972-01-01

    Comparisons of experimental and theoretical Stark profiles of the allowed 2(1)P-3(1)D helium line at 6678 A and of the forbidden 2(1)P-3(1)P component at 6632 A in a dense plasma were carried out. The plasma was produced by optical breakdown of helium by means of a repetitive, high power CO2 laser. The allowed line shows good agreement with conventional theory, but discrepancies are found around the centre of the forbidden component. When normally neglected ion motions are taken into consideration, the observed discrepancies are partially removed. Tables of the Stark profiles for the pair of lines are given.

  15. Spatio-temporal mapping of ablated species in ultrafast laser-produced graphite plasmas

    SciTech Connect

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

    2012-05-28

    We studied the spatial and temporal distributions of ionic, neutral, and molecular species generated by femtosecond laser produced plasma under varying ambient nitrogen gas pressures. Plasmas were generated by irradiating planar graphite targets using 40 fs pulses of 800 nm radiation from a Ti:Sapphire laser. The results show that in the presence of an ambient gas, the molecular species spatial extension and lifetime are directly correlated to the evolution of excited ions. The present studies also provide valuable insights into the evolution history of various species and their excitation during ultrafast laser ablation.

  16. Work function dependence of surface produced H/sup -/ in the presence of a plasma

    SciTech Connect

    Wada, M.; Pyle, R.V.; Stearns, J.W.

    1983-11-01

    The maximum H/sup -/ flux from a netatively biased converter cathode occurs at the work function minimum. A cesiated hydrogen plasma produces a partially-cesiated surface at the converter. The cesium coverage can be be controlled by the cesium partial pressure, the bias on the converter and the plasma density, while the work function of the converter surface is measured by the photo-electric effect, using a bright light source and a series of filters. The angular dependence is measured by rotating the converter.

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

    NASA Astrophysics Data System (ADS)

    Adjei, Daniel; Ayele, Mesfin Getachew; Wachulak, Przemyslaw; Bartnik, Andrzej; Wegrzynski, Łukasz; Fiedorowicz, Henryk; Vyšín, Luděk; Wiechec, Anna; Lekki, Janusz; Kwiatek, Wojciech M.; Pina, Ladislav; Davídková, Marie; Juha, Libor

    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 × 103 photons/μm2/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.

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

    NASA Astrophysics Data System (ADS)

    Pasko, V. P.

    2011-12-01

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

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

    SciTech Connect

    Derzon, M.; Nash, T.; Allshouse, G.

    1996-07-01

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

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

    SciTech Connect

    Sullivan, Enid J; Kwon, Soondong; Katz, Lynn; Kinney, Kerry

    2008-01-01

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

  1. Experimental Observation of Extreme Ultraviolet Emission from a Laser-Produced Plasma

    NASA Astrophysics Data System (ADS)

    Higashiguchi, Takeshi; Hirata, Takahiro; Kubodera, Shoichi; Sasaki, Wataru

    2002-11-01

    EUV (extreme ultraviolet) lithography technology using the multi-layer coated reflective optics requires a narrow band (< 3 %), debris-free light source in the EUV spectral region around 13 nm. EUV emission is generated from a laser plasma produced by the interaction between a Q-switched Nd:YAG laser (532 nm, 8 ns (FWHM), <200 mJ/pulse, 10 Hz) and a cryogenic target of the rare gas (krypton or xenon). The laser light is focused by a f/15 lens on the cryogenic target produced with a He gas cryostat (50 K on the target position). The emission spectra are observed with a soft x-ray spectrometer. The emission spectrum about 11 nm from the laser produced plasma is radiated from Xe^7+-Xe^8+ (4d-4p) and Xe^9+-Xe^12+ (4f-4d+4d-4p) transitions. The total output energy of the EUV emission is measured with a calibrated silicon photodiode and a 500 MHz bandwidth oscilloscope. The output energy and the conversion effeciency integrated in the solid angle of 9.5 × 10-5 sr are 21 μJ/sr/pulse and 0.01 %/sr/pulse at the laser energy of 200 mJ, respectively. Now, we are in process to observe spatial distributions of the EUV emission from the laser produced plasma.

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

    SciTech Connect

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

    2010-01-15

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

  3. Momentum transfer interaction of a laser-produced plasma with a low-pressure background.

    NASA Technical Reports Server (NTRS)

    Koopman, D. W.

    1972-01-01

    The expansion of a laser-produced metallic plasma into a photoionized hydrogen background has been experimentally studied. Langmuir probe and microwave diagnostics have detected an interaction front which decelerates with a dependence on background density and time consistent with a momentum coupling between the laser plasma and the ionized fraction of the background. An ion percursor has also been observed. Calculations of scattering cross sections indicate that multiple-encounter Coulomb scattering will dominate collisional momentum transfer. The leading edge of the laser plasma contains multiply charged ions of charge state z greater than or equal to 5, and collisional effects appear adequate to explain the principal features of the momentum coupling. The ion precursor may have a collisionless origin.

  4. Influence of a magnetic field on laser-produced Sn plasma

    NASA Astrophysics Data System (ADS)

    Lan, H.; Wang, X. B.; Chen, H.; Zuo, D. L.; Lu, P. X.

    2015-10-01

    The effects of an external magnetic field on Nd:YAG laser-produced Sn plasma have been investigated. The characteristics of ion debris from Sn plasma, emission spectra, and EUV radiation have been studied by the time-of-flight method and the optical emission spectroscopy. Our results show that the ion kinetic energies of the plume species can be effectively reduced with a modest magnetic field of 0.6 T. With the presence of a magnetic field, the spectral intensities of Sn I and Sn II show significant enhancement and the electron density of plasma is about 2 times higher. We have not found any influence of magnetic field on the characteristics of EUV emissions.

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

    SciTech Connect

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

    2011-07-15

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

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

    PubMed Central

    Spalding, EP; Goldsmith, M

    1993-01-01

    Light activates a K+ channel and transiently depolarizes the plasma membrane of Arabidopsis mesophyll cells. Genetically or chemically impairing photosynthesis abolished this electrical response to light. These results indicate that illuminated chloroplasts produce a factor that activated K+ channels in the plasma membrane. By patch clamping at the single-channel level, we have obtained evidence that ATP is one such factor. Application of 0.2 to 2 mM ATP to the cytoplasmic side of excised patches of membrane reversibly activated the type of channel that was activated by light in cell-attached patches. In addition, an outward-rectifying K+ channel and an outward-rectifying nonselective cation channel were similarly activated by ATP, whereas a nonselective stretch-activated channel was unaffected by this treatment. This novel mechanism for controlling the permeability of the plasma membrane to K+ may be important to photosynthetic metabolism. PMID:12271073

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

    SciTech Connect

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

    2009-05-21

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

  8. Parabolic lithium mirror for a laser-driven hot plasma producing device

    DOEpatents

    Baird, James K.

    1979-06-19

    A hot plasma producing device is provided, wherein pellets, singly injected, of frozen fuel are each ignited with a plurality of pulsed laser beams. Ignition takes place within a void area in liquid lithium contained within a pressure vessel. The void in the liquid lithium is created by rotating the pressure vessel such that the free liquid surface of molten lithium therein forms a paraboloid of revolution. The paraboloid functions as a laser mirror with a reflectivity greater than 90%. A hot plasma is produced when each of the frozen deuterium-tritium pellets sequentially arrive at the paraboloid focus, at which time each pellet is illuminated by the plurality of pulsed lasers whose rays pass through circular annuli across the top of the paraboloid. The beams from the lasers are respectively directed by associated mirrors, or by means of a single conical mirror in another embodiment, and by the mirror-like paraboloid formed by the rotating liquid lithium onto the fuel pellet such that the optical flux reaching the pellet can be made to be uniform over 96% of the pellet surface area. The very hot plasma produced by the action of the lasers on the respective singly injected fuel pellets in turn produces a copious quantity of neutrons and X-rays such that the device has utility as a neutron source or as an x-ray source. In addition, the neutrons produced in the device may be utilized to produce tritium in a lithium blanket and is thus a mechanism for producing tritium.

  9. Time-resolved visible spectroscopy of laser-produced lithium plasmas

    SciTech Connect

    Bailey, J.; Tisone, G.C.; Hurst, M.J.; Morrison, R.L.; Bieg, K.W.

    1988-08-01

    We have measured time-resolved visible spectra emitted from a plasma formed when the output from a dye laser irradiates solid lithium. Such a plasma has potential as a source of lithium ions for ion-driven inertial confinement fusion, and it also provides a useful source for developing diagnostics. The laser delivered 0.5 J onto a 2--7-mm-diam spot, with a 900-ns pulse length. Experiments were performed with the wavelength tuned to the Li I 2s--2p resonance line at 6708 A and off resonance at 6728 A. The target was a 500--1000-A-thick Li film, vacuum evaporated in situ onto a substrate. The light from the plasma was coupled into the entrance slit of a 1-m Czerny--Turner spectrograph, and the output from the spectrograph was focused onto the input slit of a streak camera. The electron density was obtained from Stark-broadened widths of Li I 2p--4d, 2p--5d, and 2p--4s, and H I 2p--4d. An irradiance of 2 x 10/sup 6/ W/cm/sup 2/ at 6708 A resulted in a peak electron density of 3.9 x 10/sup 17/ cm/sup -3/. The density decreased at lower irradiance, with an intensity threshold of 5 x 10/sup 5/ W/cm/sup 2/ for producing an ionized plasma. The threshold for producing a plasma was higher with the laser tuned off resonance, although high-density lithium plasmas could still be formed at relatively low laser irradiance.

  10. Time-resolved visible spectroscopy of laser-produced lithium plasmas

    SciTech Connect

    Bailey, J.; Tisone, G.C.; Hurst, M.J.; Morrison, R.L.; Bieg, K.W.

    1988-01-01

    We have measured time-resolved visible spectra emitted from a plasma formed when the output from a dye laser irradiates solid lithium. Such a plasma has potential as a source of lithium ions for ion-driven inertial confiement fusion, and it also provides a useful source for developing diagnostics. The laser delivered 0.5 Joules onto a 2-7 mm diameter spot, with a 900-ns pulse length. Experiments were performed with the wavelength tuned to the Li I 2s-2p resonance line at 6708 )angstrom) and off-resonance at 6728 )angstrom). The target was a 500 to 1000 )angstrom) thick Li film, vacuum evaporated in situ onto a substrate. The light from the plasma was coupled into the entrance slit of a 1-m Czerny-Turner spctrometer, and the output from the spectrometer was focused onto the input slit of a steak camera. The electron density was obtained from Stark broadened widths of Li I 2p-4d, 2p-5d, 2p-4s, and H I 2p-4d. An irradiance of 2 x 10/sup 6/ wcm/sup 2/ at 6708)angstrom) resulted in a peak electron density of 3.9 x 10/sup 17/ cm/sup )minus/3). The density decreased at lower irradiance, with an intensity threshold of 5 x 10/sup 5/ Wcm/sup 2/ for producing an ionized plasma. The threshold for producing a plasma was higher with the laser tuned off resonance, although high density lithium plasmas could still be formed at relatively lower laser irradiance. 6 refs., 4 figs

  11. Study of Plasma Treatment of Produced Water from Oil and Gas Exploration

    NASA Astrophysics Data System (ADS)

    Wright, Kamau

    Unconventional gas and hydraulic fracturing is helping to increase natural gas production, which is widely viewed in the U.S. as a key asset to bolstering a clean and energy-independent future. Safe and economical management and treatment of water produced during such processes remain of key importance. With the increase of hydrocarbon production and national shale gas production expected to increase threefold and account for nearly half of all natural gas produced by 2035, advanced water treatment and management processes must be investigated, to ensure water conservation and associated economic prudence. The state of the art of produced water treatment technologies is described including the efficacy of plasma to modulate the contents of such aqueous solutions, meeting target parameters and potentially enabling the operation of other treatment technologies. Among other effects, progress is presented on the enhancement of an arc-in-water system to remove bicarbonate ions and prevent the mineral fouling ability of water which causes formation of CaCO3 in heat exchangers and distillation units. Qualitative and quantitative treatment targets of produced water treatment are discussed. Experimental work is conducted to test theories and identify and reproduce favorable effects useful to treating wastewaters. Plasma arc-in-water systems demonstrated capability of producing bicarbonate-depleted wastewaters, with experiments with gas-field produced waters indicating that generation of H+ ions plays a greater role in bicarbonate ion removal than local heating. Tests showed abatement of bicarbonate ions from a range of 684--778 mg/L down to zero. Subsequent scaling/fouling tests with waters ranging from 0 to 500 mg/L bicarbonate ions, in the presence of high calcium ion concentrations, showed that scale thickness, as well as mass on a 1-kW heating element was an order of magnitude less for process water containing 100 mg/L bicarbonate ions compared to process water with 500 mg/L of bicarbonate ions. Water with bicarbonate ion concentration approaching zero resulted in prevention of scale. To enhance this new plasma induced fouling mitigation method, a plasma arc-in-water reactor was re-engineered, using a ground electrode, and two high-voltage electrodes, to stretch the arc discharge in water and increase contact between plasma and water. Results of simultaneous effects were also collected, showing within 5 min, a 4-log reduction in both Sulfate Reducing Bacteria (SRB) and Acid Producing Bacteria (APB), bacteria that are characteristic of oil-field produced waters; as well as oxidation of organics, with degradation of visually observable organics within 3 minutes, and decrease of oil and grease from 40 mg/L to under 10 mg/L within one min. With an arc-in-water system utilizing a stretched arc, simultaneous effects were exhibited on fouling ability of produced water, inactivation of bacteria, and degradation of organics. Plasma discharges in water represent a unique option in the treatment of produced waters from oil and gas production. While the water softening capabilities of arc-in-water systems present a new method for fouling mitigation and remediation of scale in heat exchangers, the simultaneous effects, including oxidation of organics and inactivation of bacteria, may allow application of plasma to water, to satisfy treatment targets that allow for the reuse of such waters in oil and gas operations.

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

    SciTech Connect

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

    2009-07-15

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

  13. Activated air produced by shielded sliding discharge plasma mediates plasmid DNA delivery to mammalian cells.

    PubMed

    Edelblute, Chelsea M; Heller, Loree C; Malik, Muhammad A; Heller, Richard

    2015-12-01

    Cold plasma is emerging as a potential method for medical applications. The current study assessed the efficacy of a novel cold plasma reactor based on shielded sliding discharge producing cathode-directed streamers generated in ambient air for the delivery of plasmid DNA. Experiments were performed with mouse melanoma cells (B16F10) and human keratinocyte cells (HaCaT) inoculated with plasmid DNA encoding luciferase. Quantitative results measured over a 72-h period displayed luciferase expression levels as high as 5-fold greater in cells exposed to plasma-activated air (PAA) than levels obtained from the inoculation of plasmid DNA alone (P?plasma for DNA delivery is attractive as it provides a non-viral, non-invasive method where the electrode or the plasma itself never directly contacts the exposed site. The current device design provides localized DNA transfer using a novel technology. Our report suggests PAA warrants further exploration as an alternative or supplemental approach for DNA transfer. PMID:26041378

  14. Modification of semiconductor materials with the use of plasma produced by low intensity repetitive laser pulses

    NASA Astrophysics Data System (ADS)

    Wolowski, J.; Rosi?ski, M.; Badziak, J.; Czarnecka, A.; Parys, P.; Turan, R.; Yerci, S.

    2008-03-01

    This work reports experiments concerning specific application of laser-produced plasma at IPPLM in Warsaw. A repetitive pulse laser system of parameters: energy up to 0.8 J in a 3.5 ns-pulse, wavelength of 1.06 ?m, repetition rate of up to 10 Hz, has been employed in these investigations. The characterisation of laser-produced plasma was performed with the use of "time-of-flight" ion diagnostics simultaneously with other diagnostic methods. The results of laser-matter interaction were obtained in dependence on laser pulse parameters, illumination geometry and target material. The modified SiO2 layers and sample surface properties were characterised with the use of different methods at the Middle-East Technological University in Ankara and at the Warsaw University of technology. The production of the Ge nanocrystallites has been demonstrated for annealed samples prepared in different experimental conditions.

  15. Modification of semiconductor materials with the use of plasma produced by low intensity repetitive laser pulses

    SciTech Connect

    Wolowski, J.; Rosinski, M.; Badziak, J.; Czarnecka, A.; Parys, P.; Turan, R.; Yerci, S.

    2008-03-19

    This work reports experiments concerning specific application of laser-produced plasma at IPPLM in Warsaw. A repetitive pulse laser system of parameters: energy up to 0.8 J in a 3.5 ns-pulse, wavelength of 1.06 {mu}m, repetition rate of up to 10 Hz, has been employed in these investigations. The characterisation of laser-produced plasma was performed with the use of 'time-of-flight' ion diagnostics simultaneously with other diagnostic methods. The results of laser-matter interaction were obtained in dependence on laser pulse parameters, illumination geometry and target material. The modified SiO{sub 2} layers and sample surface properties were characterised with the use of different methods at the Middle-East Technological University in Ankara and at the Warsaw University of technology. The production of the Ge nanocrystallites has been demonstrated for annealed samples prepared in different experimental conditions.

  16. Collisionless shocks in laser-produced plasma generate monoenergetic high-energy proton beams

    NASA Astrophysics Data System (ADS)

    Haberberger, Dan; Tochitsky, Sergei; Fiuza, Frederico; Gong, Chao; Fonseca, Ricardo A.; Silva, Luis O.; Mori, Warren B.; Joshi, Chan

    2012-01-01

    Compact and affordable ion accelerators based on laser-produced plasmas have potential applications in many fields of science and medicine. However, the requirement of producing focusable, narrow-energy-spread, energetic beams has proved to be challenging. Here we demonstrate that laser-driven collisionless shocks can accelerate proton beams to ~20MeV with extremely narrow energy spreads of about 1% and low emittances. This is achieved using a linearly polarized train of multiterawatt CO2 laser pulses interacting with a gas-jet target. Computer simulations show that laser-heated electrons launch a collisionless shock that overtakes and reflects the protons in the slowly expanding hydrogen plasma, resulting in a narrow energy spectrum. Simulations predict the production of ~200MeV protons needed for radiotherapy by using current laser technology. These results open a way for developing a compact and versatile, high-repetition-rate ion source for medical and other applications.

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

    NASA Astrophysics Data System (ADS)

    Wu, Tao; Higashiguchi, Takeshi; Li, Bowen; Arai, Goki; Hara, Hiroyuki; Kondo, Yoshiki; Miyazaki, Takanori; Dinh, Thanh-Hung; Dunne, Padraig; OReilly, Fergal; Sokell, Emma; OSullivan, 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 17 nm region using a ? = 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 HartreeFock 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 ?n = 0, n = 44 emission from highly charged ions merges to form intense UTAs in the 4 nm region and ?n = 1, n = 45 resonance transitions UTAs dominate the 13 nm region of the Bi spectrum.

  18. Analytical characterization of plasma membrane-derived vesicles produced via osmotic and chemical vesiculation.

    PubMed

    Sarabipour, Sarvenaz; Chan, Robin B; Zhou, Bowen; Di Paolo, Gilbert; Hristova, Kalina

    2015-07-01

    Plasma membrane-derived vesicles are being used in biophysical and biochemical research as a simple, yet native-like model of the cellular membrane. Here we report on the characterization of vesicles produced via two different vesiculation methods from CHO and A431 cell lines. The first method is a recently developed method which utilizes chloride salts to induce osmotic vesiculation. The second is a well established chemical vesiculation method which uses DTT and formaldehyde. We show that both vesiculation methods produce vesicles which contain the lipid species previously reported in the plasma membrane of these cell lines. The two methods lead to small but statistically significant differences in two lipid species only; phosphatidylcholine (PC) and plasmalogen phosphatidylethanolamine (PEp). However, highly significant differences were observed in the degree of incorporation of a membrane receptor and in the degree of retention of soluble cytosolic proteins within the vesicles. PMID:25896659

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

    NASA Astrophysics Data System (ADS)

    Sanyasi Rao, Bobbili; Moorti, Anand; Rathore, Ranjana; Ali Chakera, Juzer; Anant Naik, Prasad; Dass Gupta, Parshotam

    2013-06-01

    Generation of highly collimated (?div 10 mrad), quasi-monoenergetic electron beam with peak energy 12 MeV and charge 50 pC has been experimentally demonstrated from self-guided laser wake-field acceleration (LWFA) in a plasma plume produced by laser ablation of solid nylon (C12H22N2O2)n target. A 7 TW, 45 fs Ti:sapphire laser system was used for LWFA, and the plasma plume forming pulse was derived from the Nd:YAG pump laser of the same system. The results show that a reproducible, high quality electron beam could be produced from this scheme which is simple, low cost and has the capability for high repetition rate operation.

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

    SciTech Connect

    Sanyasi Rao, Bobbili; Moorti, Anand; Rathore, Ranjana; Ali Chakera, Juzer; Anant Naik, Prasad; Dass Gupta, Parshotam

    2013-06-10

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

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

    SciTech Connect

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

    2007-05-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

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

    SciTech Connect

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

    2015-05-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

  5. Experimental astrophysics with magnetised laser-produced plasma: UV/X-ray spectroscopy, interferometry and pulsed magnetic fields

    NASA Astrophysics Data System (ADS)

    Ash, Andrew David

    2006-06-01

    This work presents an experimental investigation of the scaled simulation of high Mach number collisionless shocks found in supernovae remnants, which is part of the experimental collaboration initiated by Woolsey et al. , (Physics of Plasmas, 8, 2439, 2001). Supernovae are one of the most energetic astrophysical phenomena. They distribute new matter created inside stars throughout space and are believed to be the origin of cosmic radiation with energy below 10 15 eV. The evolution of a supernova remnant is governed by the presence of strong forward and reverse shocks and diffusive shock acceleration. Some aspects of these processes can be investigated in the laboratory using scaled experiments with laser produced plasma. The experiments explore the interaction of two rapidly expanding collisionless laser produced plasmas in a magnetic field of up to 12 tesla. The plasmas are produced by multi-beam laser irradiation of 0.1 mm thick C ~12 H ~16 plastic targets by an 80 ps pulse of wavelength 1053 nm focused to an irradiance of between 10 13 W/cm 2 and 10 14 W/cm 2 , which results in expansion velocities of up to 1.5 10 8 cm/s. Measurements of the plasma electron density between 10 17 cm -3 and 10 19 cm - 3 are made by interferometry of a 20 ps probe laser pulse at a wavelength of 527 nm and evidence of collisionless interaction between the plasmas is obtained using shadowgram imaging of the probe refracted by the plasmas. Two methods to produce a strong external magnetic field are investigated. In one approach, a laser-driven Helmholtz coil is used providing a magnetic field of 8 tesla in a 20 ns pulse. The field is generated by the circulation of a large return current in a Helmholtz coil. This relies on the generation of a population of hot electrons by resonance absorption of the laser. The hot and cold electron temperatures are estimated from the x-ray bremsstrahlung emission from the target, which is measured by pulse height spectroscopy using a charge coupled device image array. In another approach, a field of up to 12 tesla in a 1.5 ms pulse is generated in an electromagnet driven by a 13 kJ, 2.8 kV capacitor bank. The resulting plasma magnetisation is measured by ultraviolet spectroscopy of Zeeman splitting in the carbon V 1s2s 3 S 1 -1s2p 3 P 2,1,0 triplet at ~2270 and the carbon III 1s 2 2s2p 1 P 1 -1s 2 2p 2 1 D 2 line at 2296.9 .

  6. Observation of forward breakdown mechanism in high-pressure argon plasma produced by irradiation by an excimer laser

    SciTech Connect

    Tsuda, N.; Yamada, J.

    1997-01-01

    When a XeCl excimer laser beam was focused in a high-pressure argon gas up to 150 atm, a hot and dense plasma was produced at the focal spot. The plasma developed not only backward but also forward, which differed from one produced by a visible laser. The radius of the forward plasma became smaller beyond the focal spot. There had been no explanation for the development mechanism of the forward plasma. A new model for the forward development mechanism called a forward breakdown wave was proposed. The forward plasma was calculated assuming that the laser beam transmitted through the plasma was further focused by the plasma. This model could predict the forward development behavior considerably well. {copyright} {ital 1997 American Institute of Physics.}

  7. Time-resolved visible and extreme ultraviolet spectroscopy of laser-produced tin plasma

    NASA Astrophysics Data System (ADS)

    O'Shay, Joseph Fred

    Previous experimental studies of laser-matter interactions have often been conducted without sufficient accuracy or attention to critical laser parameters. Moreover, much of the work published in the open literature lacks the essential theoretical underpinnings necessary to explain observations and provide predictive capability for future experiments. In this study, we use nanosecond-resolved spectroscopic techniques to investigate fundamental physics in laser-produced tin plasma, and overcome these shortcomings by implementing several metrological innovations to ensure the accuracy of experimental data. Furthermore, we present a side-by-side comparison of experimental results with computational modeling to advance our understanding of the many nonlinear, interrelated processes that occur within transient tin plasma. This dissertation is divided into three primary sections. In the first section, we study the physics governing the generation and early-time evolution of tin plasma in the low-irradiance regime: IL ˜ 4 x 1011 - 1 x 1012W/cm2 . A two-channel XUV photodiode spectrometer has been developed to measure tin plasma temperature, as well as diagnose radiation transport processes during the laser irradiation phase. During laser heating, the radiation spectrum from semi-infinite tin targets was found to approach the blackbody limit in the 10--80 nm spectral range. Through one-dimensional numerical modeling, this is shown to be due to the penetration of a radiative diffusion wave beyond the critical depth. Analysis of the time-dependent tin emission spectrum has shown that nearly 30% of the incident laser energy is converted to energetic photons in the spectral range of 15 < hv < 120 eV. The equilibrium radiation temperature, characteristic of the optically thick ablation front, has shown reasonable agreement with numerical predictions despite the model's limited dimensionality. The second part of this work examines the late-time hydrodynamics associated with the radiative plasma phase studied in the preceding section. Nanosecond-gated optical emission spectroscopy is employed to diagnose electron temperature, electron density, and propagation velocity of the ablation plume. In contrast to the large change in radiation temperature observed for a factor of three increase in laser intensity, it is found that the post-pulse plume hydrodynamics is not significantly affected for the same variation in irradiation conditions. At late times, the ion kinetic energy is found to exceed electron thermal energy by more than 100 times, which serves as a lower bound on the ratio to the ion thermal counterpart. The expanding laser-produced tin plasma is well described by a cylindrical hydrodynamic transport model; a comparison between time-integrated experimental and numerical plasma energy density has shown convergence to within a factor of two. At distances > 3 mm from the target, it was found that the heavy ion tin plasma transitions from Boltzmann to coronal equilibrium, rendering LTE assumptions in the spectral deconvolution procedure invalid. In the final section of this study, we investigate the radiative properties of tin ablation plasma as the laser irradiance is varied by more than an order of magnitude. The effect of increased focused laser energy is manifested in a weak scaling of radiation temperature, and a significant broadening of the emission lifetime at the highest laser intensities. It is found that the resulting radiation conversion efficiency is not a strong function of laser intensity within the parameter regime of this work. It is shown that agreement between experimental and simulated plasma conditions becomes progressively worse in the high-irradiance regime as the ionization and radiative transfer models play increasingly dominant roles in the plasma energetics.

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

    DOEpatents

    Marcus, Frederick 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.

  9. Specific In Situ Visualization of Plasma Cells Producing Antibodies against Porphyromonas gingivalis in Gingival Radicular Cyst

    PubMed Central

    Tsuge, Shinya; Mizutani, Yasuyoshi; Matsuoka, Kazuhiro; Sawasaki, Tatsuya; Endo, Yaeta; Naruishi, Koji; Maeda, Hiroshi; Takashiba, Shogo; Shiogama, Kazuya; Inada, Ken-ichi; Tsutsumi, Yutaka

    2011-01-01

    The enzyme-labeled antigen method was applied to visualize plasma cells producing antibodies to Porphyromonas gingivalis, flora of the human oral cavity. Antibodies to P. gingivalis have reportedly been detected in sera of patients with periodontitis. Biotinylated bacterial antigens, Ag53, and four gingipain domains (Arg-pro, Arg-hgp, Lys-pro, and Lys-hgp) were prepared by the cell-free protein synthesis system using the wheat germ extract. In paraformaldehyde-fixed frozen sections of rat lymph nodes experimentally immunized with Ag53-positive and Ag53-negative P. gingivalis, plasma cells were labeled with biotinylated Arg-hgp and Lys-hgp. Antibodies to Ag53 were detected only in the nodes immunized with Ag53-positive bacteria. In two of eight lesions of gingival radicular cyst with inflammatory infiltration, CD138-positive plasma cells in frozen sections were signalized for Arg-hgp and Lys-hgp. An absorption study using unlabeled antigens confirmed the specificity of staining. The AlphaScreen method identified the same-type antibodies in tissue extracts but not in sera. Antibodies to Ag53, Arg-pro, and Lys-pro were undetectable. In two cases, serum antibodies to Arg-hgp and Lys-hgp were AlphaScreen positive, whereas plasma cells were scarcely observed within the lesions. These findings indicate the validity of the enzyme-labeled antigen method. This is the very first application of this novel histochemical technique to human clinical samples. PMID:21525188

  10. Modeling of laser produced plasma and z-pinch x-ray lasers

    SciTech Connect

    Dunn, J; Frati, M; Gonzales, J J; Kalashnikov, M P; Marconi, M C; Moreno, C H; Nickels, P V; Osterheld, A L; Rocca, J J; Sandner, W; Shlyaptsev, V N

    1999-02-07

    In this work we describe our theoretical activities in two directions of interest. First, we discuss progress in modeling laser produced plasmas mostly related to transient collisional excitation scheme experiments with Ne- and recently with Ni-like ions. Calculations related to the delay between laser pulses, transient gain duration and hybrid laser/capillary approach are described in more detail. Second, the capillary discharge plasma research, extended to wider range of currents and rise-times has been outlined. We have systematically evaluated the major plasma and atomic kinetic properties by comparing near- and far-field X-ray laser output with that for the capillary Argon X-ray laser operating under typical current values. Consistent with the experiment insight was obtained for the 469{angstrom} X-ray laser shadowgraphy experiments with very small kiloamp currents. At higher currents, as much as {approximately}200 kA we evaluated plasma temperature, density and compared x-ray source size and emitted spectra.

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

    DOE PAGESBeta

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

    2015-04-08

    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 (PIC) simulations predict a stronger flux compressionmore » 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.« less

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

    DOE PAGESBeta

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

    2015-04-01

    Novel experiments to study the strongly-driven collision of parallel magnetic fields in ß~10, laser-produced plasmas have been conducted using monoenergetic proton radiography. These experiments were designed to probe the process of magnetic flux pileup, which has been identified in prior laser-plasma experiments as a key physical mechanism in the reconnection of anti-parallel magnetic fields when the reconnection inflow is dominated by strong plasma flows. In the present experiments using colliding plasmas carrying parallel magnetic fields, the magnetic flux is found to be conserved and slightly compressed in the collision region. Two-dimensional (2D) particle-in-cell (PIC) simulations predict a stronger flux compressionmore » 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.« less

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  14. Resonant third harmonic generation in a laser produced thin foil plasma

    NASA Astrophysics Data System (ADS)

    Kaur, Sukhdeep; Sharma, A. K.

    2008-10-01

    An analytical model is developed for third harmonic generation (THG) efficiency from a high-density inhomogeneous plasma produced by laser irradiation of a thin metallic film. The laser suffers strong reflection from the critical layer. The superposition of forward and backward waves creates a quasistatic density ripple of wave number 2k and a second harmonic density ripple at 2?, 4k, where ? and k are the frequency and wave number of the laser. The density ripple couples with the oscillatory electron velocity at ?, k to produce a nonlinear current at 3?, 5k driving a resonant third harmonic radiation in the region where 5k =k3 and k3 is the wave number at 3? frequency. As the density scale length of the plasma is increased, the efficiency of THG increases. The same behavior is reproduced in two particle in cell simulation by launching a laser in a rippled density underdense plasma of phase-matched density and a ripple period of half-laser wavelength.

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

    NASA Astrophysics Data System (ADS)

    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 <10 ms and the distribution altered when 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.

  16. Filamentation effects and second-harmonic spectra in laser-produced plasmas

    SciTech Connect

    Khalfaoui, A.H.; Abdelli, S.; Kerdja, T.; Ghobrini, D. )

    1993-08-01

    Sideway scattered second-harmonic spectra emitted from a 1064-nm-laser-produced plasma have been observed to originate from nonlinear coupling near the critical surface. The time evolution of the second-harmonic optical density confirmed the possibility that a plasmon issued from the resonant absorption of the incident beam can recombine with a photon ([omega][sub 0]) to give a transverse wave of frequency 2[omega][sub 0]. A plasmon issued from a parametric decay instability may also, by coalescence with an incident photon, give a transverse wave at a shifted second-harmonic frequency. The threshold of such a combination is determined. Moreover, irregular plasma-parameter variations and the perturbed spatial uniformity of the incident beam appear to alter the second-harmonic spectra. An oscillatory structure of the optical density of the observed second harmonic is interpreted as a result of the coupling physics involved and of laser-beam filamentation.

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

    NASA Astrophysics Data System (ADS)

    Vera, L. P.; Prez, J. A.; Riascos, H.

    2014-05-01

    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 C2 Swan System (d3?g?a3?u), the First Negative System N2 (Band head at 501,53 nm) and emission lines of the C I, C II, 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 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 x1018 cm-3 respectively.

  18. Development of a Time-resolved Soft X-ray Spectrometer for Laser Produced Plasma Experiments

    SciTech Connect

    Cone, K V; Dunn, J; Schneider, M B; Baldis, H A; Brown, G V; Emig, J; James, D L; May, M J; Park, J; Shepherd, R; Widmann, K

    2010-05-12

    A 2400 line/mm variable spaced grating spectrometer (VSG) has been used to measure soft x-ray emission (8-22 {angstrom}) from laser-produced plasma experiments at Lawrence Livermore National Laboratory's Compact Multipulse Terrawatt (COMET) Laser Facility. The spectrometer was coupled to a Kentech x-ray streak camera to study the temporal evolution of soft x-rays emitted from the back of mylar and copper foils irradiated at 10{sup 15} W/cm{sup 2}. The instrument demonstrated a resolving power of {approx} 120 at 19 {angstrom} with a time resolution of 31 ps. The time-resolved copper emission spectrum was consistent with a photodiode monitoring the laser temporal pulse shape and indicated that the soft x-ray emission follows the laser heating of the target. The time and spectral resolution of this diagnostic make it useful for studies of high temperature plasmas.

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

    SciTech Connect

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

    2013-09-21

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

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

    PubMed

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

    2014-04-30

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

  1. Development of a time-resolved soft x-ray spectrometer for laser produced plasma experiments

    SciTech Connect

    Cone, K. V.; Park, J.; Dunn, J.; Schneider, M. B.; Brown, G. V.; Emig, J.; James, D. L.; May, M. J.; Shepherd, R.; Widmann, K.; Baldis, H. A.

    2010-10-15

    A 2400 lines/mm variable-spaced grating spectrometer has been used to measure soft x-ray emission (8-22 A) from laser-produced plasma experiments at Lawrence Livermore National Laboratory's Compact Multipulse Terrawatt (COMET) Laser Facility. The spectrometer was coupled to a Kentech x-ray streak camera to study the temporal evolution of soft x rays emitted from the back of the Mylar and the copper foils irradiated at 10{sup 15} W/cm{sup 2}. The instrument demonstrated a resolving power of {approx}120 at 19 A with a time resolution of 31 ps. The time-resolved copper emission spectrum was consistent with a photodiode monitoring the laser temporal pulse shape and indicated that the soft x-ray emission follows the laser heating of the target. The time and spectral resolutions of this diagnostic make it useful for studies of high temperature plasmas.

  2. Spectra of plasmas of Ru, Rh, Pd and Mo produced with nanosecond and picosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Lokasani, Ragava; Long, Elaine; Sheridan, Paul; Hayden, Patrick; O'Reilly, Fergal; Dunne, Padraig; Endo, Akira; Limpouch, Jiri; O'Sullivan, Gerry

    2015-05-01

    This paper describes the extreme ultraviolet and soft x-ray emission recorded in the 2-12 nm region from Mo, Ru, Rh and Pd ions present in the laser produced plasmas. The spectra were found to be dominated by 3p-3d transitions in the 5-8 nm region, which shift slowly to shorter wavelengths with the increasing atomic number, and by 3d-4p and 3d-4f transitions at shorter wavelengths. These transitions, in a number of neighbouring ion stages, were distinguished by comparison with Cowan code calculations and previously reported data. The experimental results show that strong emission can be observed at the 6.X nm region for Ru, Rh and Pd plasmas.

  3. Development of a time-resolved soft x-ray spectrometer for laser produced plasma experiments.

    PubMed

    Cone, K V; Dunn, J; Schneider, M B; Baldis, H A; Brown, G V; Emig, J; James, D L; May, M J; Park, J; Shepherd, R; Widmann, K

    2010-10-01

    A 2400 lines/mm variable-spaced grating spectrometer has been used to measure soft x-ray emission (8-22 A?) from laser-produced plasma experiments at Lawrence Livermore National Laboratory's Compact Multipulse Terrawatt (COMET) Laser Facility. The spectrometer was coupled to a Kentech x-ray streak camera to study the temporal evolution of soft x rays emitted from the back of the Mylar and the copper foils irradiated at 10(15)?W/cm(2). The instrument demonstrated a resolving power of ?120 at 19 A? with a time resolution of 31 ps. The time-resolved copper emission spectrum was consistent with a photodiode monitoring the laser temporal pulse shape and indicated that the soft x-ray emission follows the laser heating of the target. The time and spectral resolutions of this diagnostic make it useful for studies of high temperature plasmas. PMID:21034016

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

    SciTech Connect

    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.

    1997-01-05

    The time and space-integrated emission spectra measurements have been performed in plasma produced by 308 nm wavelength XeCl laser radiation (I{sub L}=(4-10){center_dot}10{sup 12} W/cm{sup 2}, {tau}=10 ns) and by 248 nm wavelength KrF laser pulse train radiation I{sub L}=5{center_dot}10{sup 15} W/cm{sup 2}, {tau}=7 ps, 16 pulses in train) on (CF{sub 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.

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

    SciTech Connect

    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{sub L}=(4{minus}10){center_dot}10{sup 12} W/cm{sup 2}, {tau}=10 ns) and by 248 nm wavelength KrF laser pulse train radiation (I{sub L}=5{center_dot}10{sup 15} W/cm{sup 2}, {tau}=7 ps, 16 pulses in train) on CF{sub 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.

  6. Correlation between laser absorption and radiation conversion efficiency in laser produced tin plasma

    NASA Astrophysics Data System (ADS)

    Matsukuma, Hiraku; Sunahara, Atsushi; Yanagida, Tatsuya; Tomuro, Hiroaki; Kouge, Kouichiro; Kodama, Takeshi; Hosoda, Tatsuya; Fujioka, Shinsuke; Nishimura, Hiroaki

    2015-09-01

    The correlation between the laser absorption and the conversion efficiency (CE) for 13.5 nm extreme ultraviolet (EUV) light in a laser-produced tin plasma was investigated. The absorption rate ? and the CE were measured simultaneously for a laser-pre-formed low-density tin target as a function of the time delay between the pre-pulse and the main laser pulse. A clear and positive correlation between ? and CE was found with increasing delay time; however, the CE decreases rapidly at longer delay times. This result is partly attributed to a reduction in the absorption rate, but is mainly attributed to the self-absorption of EUV light in excessively long-scale plasmas.

  7. Production of geopolymers using glass produced from DC plasma treatment of air pollution control (APC) residues.

    PubMed

    Kourti, Ioanna; Rani, D Amutha; Deegan, D; Boccaccini, A R; Cheeseman, C R

    2010-04-15

    Air pollution control (APC) residues are the hazardous waste produced from cleaning gaseous emissions at energy-from-waste (EfW) facilities processing municipal solid waste (MSW). APC residues have been blended with glass-forming additives and treated using DC plasma technology to produce a high calcium alumino-silicate glass. This research has investigated the optimisation and properties of geopolymers prepared from this glass. Work has shown that high strength geopolymers can be formed and that the NaOH concentration of the activating solution significantly affects the properties. The broad particle size distribution of the APC residue glass used in these experiments results in a microstructure that contains unreacted glass particles included within a geopolymer binder phase. The high calcium content of APC residues may cause the formation of some amorphous calcium silicate hydrate (C-S-H) gel. A mix prepared with S/L=3.4, Si/Al=2.6 and [NaOH]=6M in the activating solution, produced high strength geopolymers with compressive strengths of approximately 130 MPa. This material had high density (2070 kg/m(3)) and low porosity. The research demonstrates for the first time that glass derived from DC plasma treatment of APC residues can be used to form high strength geopolymer-glass composites that have potential for use in a range of applications. PMID:20022170

  8. Spark plasma sintering of alumina nanopowders produced by electrical explosion of wires.

    PubMed

    An, Vladimir; Khasanov, Alexey; de Izarra, Charles

    2015-01-01

    Alumina nanopowders produced by electrical explosion of wires were sintered using the spark plasma sintering technique. The results of XRD analysis show that the main phase in the compacted nanopowders is α-Al2O3. According to the SEM observations, the sintered alumina nanopowder consists of micron-sized faceted grains and nano-sized necked grains. The increase in sintering temperature resulted in a higher density of the sintered powders: from 78.44 to 98.21 % of theoretical density. PMID:26543716

  9. Amorphous Alloys with Nitride Particles Produced by a Nitrogen Plasma-Alloy Reaction

    NASA Astrophysics Data System (ADS)

    Inoue, Akihisa; Oguchi, Masahiro; Kim, Byung Geol; Misaki, Hitoshi; Masumoto, Tsuyoshi

    1988-02-01

    By taking advantage of the high reactivity of nitrogen plasma with molten metal in arc melting, an amorphous foil with ZrN or NbN particles was produced for easy glass-forming Fe-Cr-Mo-P-C alloys containing Zr or Nb. The application of melt spinning to the duplex-phase foils was found to bring about the formation of an amorphous alloy ribbon having dispersed ZrN or NbN particles. The new processing technique and the duplex amorphous alloys are expected to attract increasing attention because of the possibility of multifunctional characteristics which are not obtained for an amorphous single phase.

  10. [Aspergillus ochraceus myxomycetes produce extracellular proteinases--protein C activators of blood plasma].

    PubMed

    Osmolovskiĭ, A A; Kreĭer, V G; Kurakov, A V; Baranova, N A; Egorov, N S

    2012-01-01

    Natural isolates of Aspergillus ochraceus myxomycetes from soil and plant remains from various regions have been screened. The isolated strains were characterized by similar cultural and morphological features and an identical nucleotide sequence in the ITS1-5,8S-ITS2 region of rDNA. The ability of the extracellular proteinases of A. ochraceus myxomycetes to activate protein C of blood plasma has been established. Differences are revealed in the accumulation of proteinases activating protein C and proteinases with thrombin- and plasmin-like activities in the growth dynamics of producers. PMID:23101392

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

    NASA Astrophysics Data System (ADS)

    Nayak, B. B.

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

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

    SciTech Connect

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

    1994-10-01

    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.

  14. Generation of metal ions in the beam plasma produced by a forevacuum-pressure electron beam source

    NASA Astrophysics Data System (ADS)

    Tyunkov, A. V.; Yushkov, Yu. G.; Zolotukhin, D. B.; Savkin, K. P.; Klimov, A. S.

    2014-12-01

    We report on the production of metal ions of magnesium and zinc in the beam plasma formed by a forevacuum-pressure electron source. Magnesium and zinc vapor were generated by electron beam evaporation from a crucible and subsequently ionized by electron impact from the e-beam itself. Both gaseous and metallic plasmas were separately produced and characterized using a modified RGA-100 quadrupole mass-spectrometer. The fractional composition of metal isotopes in the plasma corresponds to their fractional natural abundance.

  15. Generation of metal ions in the beam plasma produced by a forevacuum-pressure electron beam source

    SciTech Connect

    Tyunkov, A. V.; Yushkov, Yu. G. Zolotukhin, D. B.; Klimov, A. S.; Savkin, K. P.

    2014-12-15

    We report on the production of metal ions of magnesium and zinc in the beam plasma formed by a forevacuum-pressure electron source. Magnesium and zinc vapor were generated by electron beam evaporation from a crucible and subsequently ionized by electron impact from the e-beam itself. Both gaseous and metallic plasmas were separately produced and characterized using a modified RGA-100 quadrupole mass-spectrometer. The fractional composition of metal isotopes in the plasma corresponds to their fractional natural abundance.

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

    PubMed

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

    2015-12-30

    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. PMID:26282219

  17. Study on hydrogen retention produced from reaction of FLiNaK in ECR plasma

    NASA Astrophysics Data System (ADS)

    Park, Hyunjae; Choi, Yong-Sup; Lho, Taiheop; Plasma Fundamental Technology Development Team

    2011-10-01

    In this study, hydrogen retention from the interaction between an electron cyclone resonance (ECR) plasma and a molten salt, has been experimentally investigated. FLiNaK, which is comprised of LiF (46.5 mol%), NaF (11.5 mol%), and KF (42 mol%), has been used as a molten salt. The molten salt was prepared at the base pressure of 2 10-6 torr and 500C which is above the melting point. However, the chamber pressure was increased up to 3 105 mTorr owing to the outgassing from the mixture. The experiments have been perfromed at the working pressure of 1 mTorr at different reaction times. The electron temperature and the ion density in hydrogen ECR plasma were measured by making use of Langmuir probe. Retention of hydrogen in FLiNaK was investigated by means of TDS (Thermal Desorption Spectrometry) method. The chemical species produced from the interaction between the plasma and the molten salt by an optical emission spectroscopy (OES) and a residual gas analyzer (RGA) have been also observed.

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

    SciTech Connect

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

    2014-09-15

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

  19. Investigation of the state of local thermodynamic equilibrium of a laser-produced aluminum plasma.

    PubMed

    Barthlemy, Olivier; Margot, Jolle; Laville, Stphane; Vidal, Franois; Chaker, Mohamed; Le Drogoff, Boris; Johnston, Tudor W; Sabsabi, Mohamad

    2005-04-01

    In this work, the assumption of local thermodynamic equilibrium (LTE) for a laser-induced plasma in ambient air is examined experimentally using two different laser systems, namely an infrared short-pulse Ti : Sapphire laser and an ultraviolet long-pulse XeCl excimer laser. The LTE assumption is investigated by examining the plasma produced at a laser fluence of 10 J/cm(2) from aluminum targets containing iron and magnesium impurities. The excitation temperature is deduced from Boltzmann diagrams built from a large number of spatially integrated neutral iron lines distributed from 3.21 to 6.56 eV. It is shown that at any time after the end of the laser pulse, the neutral excited states are in excellent Boltzmann equilibrium. Detailed investigation of Boltzmann equilibrium further validates previous temperature measurements using less accurate diagrams. However, observations of ion lines provide some evidence that the ionized species do not obey Saha equilibrium, thereby indicating departure from LTE. This could be explained by the fact that the plasma cannot be considered as stationary for these species. PMID:15901339

  20. Particle emission from tantalum plasma produced by 532 nm laser pulse ablation

    SciTech Connect

    Torrisi, L.; Caridi, F.; Picciotto, A.; Margarone, D.; Borrielli, A.

    2006-11-01

    A study of visible laser ablation of tantalum in vacuum by using 3 ns Nd:YAG laser radiation at high pulse energy is reported. Nanosecond pulsed ablation, at an intensity on the order of 10{sup 9} W/cm{sup 2}, produces high nonisotropic emission of neutrals and ionic species. Mass quadrupole spectrometry, coupled to electrostatic ion deflection, allows estimation of the energy distributions of the emitted species within the plume as a function of the incident laser energy. Neutrals show typical Boltzmann distributions while ions show Coulomb-Boltzmann-shifted distributions depending on their charge state. Surface profiles of the craters and microscopy investigations permitted to study the ablation threshold, ablation yields, and deposition rates of thin films on silicon substrates. The multicomponent structure of the plume emission is rationalized in terms of charge state, ion and neutral equivalent temperatures, and plasma density. A special regard is given to the ion acceleration process occurring inside the plasma due to the high electrical field generated at the nonequilibrium plasma conditions. The angular distributions of the neutral and ion species are also presented and discussed.

  1. Ion and atomic species produced in large scale oxygen plasma used for treatments sensitive materials

    NASA Astrophysics Data System (ADS)

    Spasic, Kosta; Skoro, Nikola; Puac, Nevena; Malovic, Gordana; Petrovic, Zoran Lj.

    2013-09-01

    Asymmetric CCP plasma system operating at 13.56 MHz was successfully used for treatments of textile, seeds and polymers. Central electrode (aluminium rod) was powered electrode while the cylindrical wall of the chamber was grounded electrode. We have used mass spectrometry for detections of ions and neutrals in order to get better insight in plasma chemistry involved in surface reactions on treated samples. Besides of ions, one of the important species for surface modifications is atomic oxygen. Actinometry was used as an additional diagnostic tool to determine the extent of atomic oxygen produced in plasma. Measurements were made in several different mixtures of oxygen with addition of several percent of argon. The range of pressures investigated was 150 to 450 mTorr for powers from 100 to 500 W. Measured atomic oxygen density has a steady rise with power (1019-1020 m-3) . Apart from atomic oxygen species we have detected mass spectra of positive and negative ions. Most abundant ion was O2+while the amounts of O+ and O- were smaller by the order of magnitude compared to O2+. Supported by MESTD, RS, III41011 and ON 171037.

  2. Emission dynamics of an expanding ultrafast-laser produced Zn plasma under different ambient pressures

    SciTech Connect

    Smijesh, N.; Philip, Reji

    2013-09-07

    We report time and space resolved spectral measurements of neutral Zn emission from an ultrafast laser produced plasma, generated by the irradiation of a Zn target with laser pulses of 100 femtoseconds duration, carried out in a broad ambient pressure range of 0.05 to 100 Torr. The measurement is done for three different axial positions in the expanding plume. The spectra are rich in neutral Zn (Zn I) emissions at 334.5 nm, 468 nm, 472 nm, 481 nm, and 636 nm, respectively, depicting the characteristic triplet structure of Zn. Fast as well as slow peaks are observed in the time of flight data of 481 nm emission, which arise from recombination and atomic contributions, respectively, occurring at different time scales. Average speeds of the fast atomic species do not change appreciably with ambient pressure. The plasma parameters (electron temperature and number density) are evaluated from the measured optical emission spectra. The rates of ionization and recombination can be enhanced by a double-pulse excitation configuration in which optical energy is coupled to the ultrafast plasma through a delayed laser pulse.

  3. The angular structure of second harmonic emission from laser-produced plasmas irradiated at moderate intensity

    SciTech Connect

    Drake, R.P.; Bauer, B.S.; Baker, K.L.; Mizuno, K.; Sleaford, B.; Rubenchik, A.M.; Estabrook, K. |; Labaune, C.; Baton, S.; Jalinaud, T.; Schifano, E.; Goldman, M.V.; Newman, D.L.

    1993-04-06

    The authors have made the first simultaneous, multi-angle measurements of the time-resolved spectrum of second-harmonic emission from a laser-produced plasma. The experiments used from 1 to 80 J of 1.053 {mu}m light to irradiate CH targets with 550 ps gaussian pulses through a random phase plate. The intensities in the range of 10{sup 13} to 10{sup 14} W/cm{sup 2} were sufficient to drive the Ion Acoustic Decay Instability well above threshold, producing Stokes emission well-separated from the emission spike at the second harmonic of the laser frequency. The spectral structure of the Stokes emission was qualitatively similar for all intensities and angles of observation.

  4. The angular structure of second harmonic emission from laser-produced plasmas irradiated at moderate intensity

    SciTech Connect

    Drake, R.P.; Bauer, B.S.; Baker, K.L.; Mizuno, K.; Sleaford, B.; Rubenchik, A.M.; Estabrook, K. California Univ., Davis, CA ); Labaune, C.; Baton, S.; Jalinaud, T.; Schifano, E. . Lab. pour l'Utilisation des Lasers Intenses); Goldman, M.V.; Newman, D.L. (Colorado Univ., Boulder, CO (United Stat

    1993-04-06

    The authors have made the first simultaneous, multi-angle measurements of the time-resolved spectrum of second-harmonic emission from a laser-produced plasma. The experiments used from 1 to 80 J of 1.053 [mu]m light to irradiate CH targets with 550 ps gaussian pulses through a random phase plate. The intensities in the range of 10[sup 13] to 10[sup 14] W/cm[sup 2] were sufficient to drive the Ion Acoustic Decay Instability well above threshold, producing Stokes emission well-separated from the emission spike at the second harmonic of the laser frequency. The spectral structure of the Stokes emission was qualitatively similar for all intensities and angles of observation.

  5. Colliding laser-produced plasmas as targets for laser-generated extreme ultraviolet sources

    SciTech Connect

    Cummins, T.; O'Gorman, C.; Dunne, P.; Sokell, E.; O'Sullivan, G.; Hayden, P.

    2014-07-28

    Colliding plasmas produced by neodymium-doped yttrium aluminium garnet (Nd:YAG) laser illumination of tin wedge targets form stagnation layers, the physical parameters of which can be controlled to optimise coupling with a carbon dioxide (CO{sub 2}) heating laser pulse and subsequent extreme ultraviolet (EUV) production. The conversion efficiency (CE) of total laser energy into EUV emission at 13.5 nm ± 1% was 3.6%. Neglecting both the energy required to form the stagnation layer and the EUV light produced before the CO{sub 2} laser pulse is incident results in a CE of 5.1% of the CO{sub 2} laser energy into EUV light.

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

    SciTech Connect

    Higashiguchi, Takeshi; Yugami, Noboru; Hikida, Masafumi; Terauchi, Hiromitsu; Bai Jinxiang; Kikuchi, Takashi; Tao Yezheng

    2010-04-15

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

  7. Radiative properties of Z-pinch and laser produced plasmas from mid-atomic-number materials

    NASA Astrophysics Data System (ADS)

    Ouart, Nicholas D.

    The investigation of Z-pinches on university-scale pulsed power generators allows for the study of plasmas with a broad range of temperatures, densities, and sizes in cost effective experiments. In particular, X-pinches produce the hottest and densest plasma and are very suitable for x-ray radiation studies. The planar wire array has shown to be a powerful radiation source on the 1 MA Zebra generator at UNR. The radiative and implosion dynamics from such loads with mid-atomic-number materials were not studied previously in detail and are a topic of this dissertation. Specifically, the radiative and implosion characteristics of Z-pinch and X-pinch plasmas with mid-atomic-number materials (iron, nickel, copper, and zinc) will be discussed. The theoretical tool used to accomplish this is non-LTE kinetic modeling. This tool is not limited to Z-pinches, but can be applied to any plasma radiation source like laser produced plasmas which will be demonstrated. In addition, since the radiative characteristics of wire arrays are connected with the implosion characteristics, another theoretical tool, the Wire Ablation Dynamics Model was used in this dissertation to understand the ablation and implosion dynamics of wire arrays. The experiments were analyzed from two university-scale pulsed power machines: the 1 MA Zebra and COBRA generators. The research completed in this dissertation emphasizes the unique capabilities and usefulness of spectroscopy, particularly time-gated x-ray spectroscopy. For example, modeling of time-gated L-shell spectra captured from the precursor column of low-wire-number copper cylindrical wire arrays reveals electron temperatures 400 eV, which is significantly higher than any previous precursor measurements. From the analysis of experiments on COBRA, total energy was higher for the implosion of a compact cylindrical wire array made with alternating brass and aluminum wires than a uniform wire array made with just brass or aluminum. Comparison of L-shell radiation from mid-atomic-number wires placed in the inner or outer array from nested wire array implosions on COBRA shows that the material radiates more when placed on the outer array. Using different materials on the outer and inner arrays provides a unique opportunity to study the implosion dynamics of nested wire arrays, especially when using time-gated spectroscopy. Brass planar wire arrays represent a unique opportunity to study the performance of two L-shell radiators from mid-atomic-number materials (copper and zinc) at the same time in experiments on Zebra. The ablation and implosion dynamics of the single- and double-planar wire arrays was investigated and completed. Non-LTE kinetic modeling was used to describe the radiation from simultaneous measurements of K- and L-shell radiation from the interaction of a femtosecond laser system with an iron target. The K- and L-shell radiation originates from two distinct plasma regions. The L-shell radiation was emitted from a region of plasma created by the prepulse and modeling showed moderate electron temperatures and electron densities. The cold iron Kalpha line manifested from a region of plasma that was heated by hot electrons interacting with the solid dense iron target. K-shell modeling showed electron temperatures of tens of eV and less than 1% hot electrons. To study the time history of cold Kalpha lines for mid-atomic-number materials, experiments with planar wire arrays were performed on Zebra. Continuation of this study was accomplished using X-pinches to allow for the simultaneous measurements in time of hotter ionic and cold K-shell lines.

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

    SciTech Connect

    Steven Brandt, E.; Grace, Jeremy M.

    2012-01-15

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

  9. Efficacy of experimentally produced spray-dried plasma on infectivity of porcine circovirus type 2.

    PubMed

    Patterson, A R; Madson, D M; Opriessnig, T

    2010-12-01

    The value of incorporating spray-dried plasma (SDP) into the diet of weanling pigs to improve feed intake and growth performance has been well documented. However, limited work has been done to confirm that the spray-drying process eliminates all viral contaminates including porcine circovirus type 2 (PCV2). To determine the effect of spray-drying on PCV2 infectivity, colostrum-fed, crossbred, specific-pathogen-free (SPF) pigs were inoculated with PCV2-contaminated SDP intraperitoneally (SDP-IP) or by oral gavage (SDP-OG), inoculated intraperitoneally with PCV2-positive plasma (POS), or left uninoculated (NEG). The plasma used for the experimentally produced SDP was collected from a SPF pig experimentally infected with a PCV2b isolate. Pigs in the NEG group remained seronegative, and PCV2 viremia was not detected. All pigs in the POS group became PCV2 viremic by 14 d postinoculation (DPI) and seroconverted by 28 DPI. In the SDP-IP group, all pigs became viremic by 35 DPI and seroconverted by 49 DPI. In the SDP-OG group, all animals became viremic by 35 DPI and 2/3 pigs seroconverted by 35 DPI. There were no significant (P > 0.05) differences between anti-PCV2-IgG antibody sample-to-positive ratios among pigs in the POS, SDP-OG, or SDP-IP groups. This work provides direct evidence that the experimental spray-drying process used in this study was not effective in inactivating PCV2b in the plasma of a PCV2-infected pig based on a swine bioassay using PCV2-nave pigs. This work suggests that SDP sourced from pigs could represent a biosecurity risk for the industry. PMID:20675601

  10. Plasma immunoreactive gamma melanotropin in patients with idiopathic hyperaldosteronism, aldosterone-producing adenomas, and essential hypertension.

    PubMed Central

    Griffing, G T; Berelowitz, B; Hudson, M; Salzman, R; Manson, J A; Aurrechia, S; Melby, J C; Pedersen, R C; Brownie, A C

    1985-01-01

    A non-ACTH aldosterone-stimulating factor(s) has been implicated in the pathogenesis of idiopathic hyperaldosteronism (IHA). Although this factor has not been fully characterized, some evidence suggests that it may be related to a pro-gamma-melanotropin (pro-gamma-MSH), derived from the NH2-terminal region of pro-opiomelanocortin. In the present study, plasma immunoreactive (IR-) gamma-MSH levels at 0800 h in patients with IHA were evaluated (90 +/- 17 fmol/ml; range: 13-173 fmol/ml) and found to be significantly higher (P less than 0.05) than those in subjects with aldosterone-producing adenomas (33 +/- 8 fmol/ml), essential hypertension (33 +/- 6 fmol/ml), and normotensive controls (19 +/- 2 fmol/ml). Seven of nine IHA subjects had circulating IR-gamma-MSH levels above the normal range (greater than 35 fmol/ml). In plasmas sampled at 1200 h, IR-gamma-MSH was significantly higher in patients with IHA (95 +/- 26 fmol/ml) and adenomas (63 +/- 23 fmol/ml), as compared with essential hypertensives (31 +/- 6 fmol/ml) and normotensives (19 +/- 3 fmol/ml). Mean plasma IR-ACTH, plasma cortisol, and urinary cortisol levels did not differ significantly between any of these groups. In order to evaluate the effect of a pro-gamma-MSH in vitro, adrenal adenoma tissue was obtained from two patients, one with elevated IR-gamma-MSH (61 fmol/ml) and a second with low IR-gamma-MSH (12 fmol/ml). Aldosterone secretion by dispersed adenoma cells from the former, but not the latter, underwent a fourfold dose-dependent (10(-14)-10(-9) M) increase in response to human Lys-gamma 3-MSH. These data suggest that a pro-gamma-MSH may be implicated as a pathogenic factor in a subset of patients with primary aldosteronism, particularly among those differentially diagnosed as having IHA. Images PMID:4019776

  11. Initial speed of knots in the plasma tail of C/2013 R1(Lovejoy)

    SciTech Connect

    Yagi, Masafumi; Furusho, Reiko; Terai, Tsuyoshi; Watanabe, Jun-Ichi; Koda, Jin; Fujiwara, Hideaki

    2015-03-01

    We report short-time variations in the plasma tail of C/2013 R1(Lovejoy). A series of short (2–3 minutes) exposure images with the 8.2 m Subaru telescope shows faint details of filaments and their motions over a 24 minute observing duration. We identified rapid movements of two knots in the plasma tail near the nucleus (∼3×10{sup 5} km). Their speeds are 20 and 25 km s{sup −1} along the tail and 3.8 and 2.2 km s{sup −1} across it, respectively. These measurements set a constraint on an acceleration model of plasma tail and knots as they set the initial speed just after their formation. We also found a rapid narrowing of the tail. After correcting the motion along the tail, the narrowing speed is estimated to be ∼8 km s{sup −1}. These rapid motions suggest the need for high time-resolution studies of comet plasma tails with a large telescope.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  14. Plasma characteristics of argon glow discharge produced by AC power supply operating at low frequencies

    NASA Astrophysics Data System (ADS)

    Kongpiboolkid, Watcharapon; Mongkolnavin, Rattachat

    2015-04-01

    Non-thermal properties of Argon glow discharge operating with various operating pressures were measured and presented in this work. The Argon plasma is produced by a parallel conducting electrodes coupling with a high voltage AC power supply. The power supply can generate high AC voltage at various frequencies. The frequencies for the operation are in the range of a few kHz. The system is capable of generating electric field between the two metal electrodes discharge system. The characteristics of plasma produced were measured by optical emission spectroscopy (OES) technique where electron temperature (Te) and electron number density (ne) can be determined by line intensity ratio method. The value of electron number density was then determined from the Saha-Eggert equation. Our results show that the electron number density of the discharge obtained is of the order of 10-17 - 10-18 m-3 where the electron temperature is between 1.00-2.00 eV for various operating frequencies used which are in good agreement with similar results published earlier.

  15. Spectroscopic study of plasmas produced by a laser equipped with distribution phase plates

    SciTech Connect

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

    1993-07-01

    The spectra emitted by Al and Si laser-produced plasmas were recorded in the region of 18--350 A. The bandlike structures observed near the Al XI and Si XII 2[ital p]--3[ital d] transitions at 52 and 44 A, respectively, are identified as Be-like dielectronic satellite transitions in Al and Si. The plasmas were produced with the Omega laser system at the Laboratory for Laser Energetics at the University of Rochester. Typical laser pulse lengths were 650 ps at a laser wavelength of 351 nm, with an intensity of 5--9[times]10[sup 14] W/cm[sup 2]. The spherical targets employed in these experiments consisted of solid-glass spheres coated with a 2 [mu]m layer of Al and an outer layer of parylene 0--8 [mu]m thick, illuminated by 24 laser beams equipped with distributed phase plates (DPP's) to improve the uniformity of illumination. The dielectronic transitions associated with the observed bands belong to the transition arrays 1[ital s][sup 2]2[ital pnl]--1[ital s][sup 2]3[ital dnl], where [ital n] is the principal quantum number (greater than 2) and [ital l] is the azimuthal quantum number of the spectator electron. The observation of Be-like dielectronic transitions suggests that this emission occurs from a lower temperature ([ital T][sub [ital e

  16. Plasma characteristics of argon glow discharge produced by AC power supply operating at low frequencies

    SciTech Connect

    Kongpiboolkid, Watcharapon; Mongkolnavin, Rattachat

    2015-04-24

    Non-thermal properties of Argon glow discharge operating with various operating pressures were measured and presented in this work. The Argon plasma is produced by a parallel conducting electrodes coupling with a high voltage AC power supply. The power supply can generate high AC voltage at various frequencies. The frequencies for the operation are in the range of a few kHz. The system is capable of generating electric field between the two metal electrodes discharge system. The characteristics of plasma produced were measured by optical emission spectroscopy (OES) technique where electron temperature (T{sub e}) and electron number density (n{sub e}) can be determined by line intensity ratio method. The value of electron number density was then determined from the Saha-Eggert equation. Our results show that the electron number density of the discharge obtained is of the order of 10{sup −17} − 10{sup −18} m{sup −3} where the electron temperature is between 1.00−2.00 eV for various operating frequencies used which are in good agreement with similar results published earlier.

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

    SciTech Connect

    Smijesh, N.; Chandrasekharan, K.; Joshi, Jagdish C.; Philip, Reji

    2014-07-07

    We report the experimental investigation and comparison of the temporal features of short-pulse (7 ns) and ultrafast (100 fs) laser produced plasmas generated from a solid nickel target, expanding into a nitrogen background. When the ambient pressure is varied in a large range of 10⁻⁶Torr to 10²Torr, the plume intensity is found to increase rapidly as the pressure crosses 1 Torr. Time of flight (TOF) spectroscopy of emission from neutral nickel (Ni I) at 361.9 nm (3d⁹(²D) 4p → 3d⁹(²D) 4s transition) reveals two peaks (fast and slow species) in short-pulse excitation and a single peak in ultrafast excitation. The fast and slow peaks represent recombined neutrals and un-ionized neutrals, respectively. TOF emission from singly ionized nickel (Ni II) studied using the 428.5 nm (3p⁶3d⁸(³P) 4s→ 3p⁶3d⁹ 4s) transition shows only a single peak for either excitation. Velocities of the neutral and ionic species are determined from TOF measurements carried out at different positions (i.e., at distances of 2 mm and 4 mm, respectively, from the target surface) on the plume axis. Measured velocities indicate acceleration of neutrals and ions, which is caused by the Coulomb pull of the electrons enveloping the plume front in the case of ultrafast excitation. Both Coulomb pull and laser-plasma interaction contribute to the acceleration in the case of short-pulse excitation. These investigations provide new information on the pressure dependent temporal behavior of nickel plasmas produced by short-pulse and ultrafast laser pulses, which have potential uses in applications such as pulsed laser deposition and laser-induced nanoparticle generation.

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

    SciTech Connect

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

    1998-03-01

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

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

    NASA Astrophysics Data System (ADS)

    Smijesh, N.; Chandrasekharan, K.; Joshi, Jagdish C.; Philip, Reji

    2014-07-01

    We report the experimental investigation and comparison of the temporal features of short-pulse (7 ns) and ultrafast (100 fs) laser produced plasmas generated from a solid nickel target, expanding into a nitrogen background. When the ambient pressure is varied in a large range of 10-6 Torr to 102 Torr, the plume intensity is found to increase rapidly as the pressure crosses 1 Torr. Time of flight (TOF) spectroscopy of emission from neutral nickel (Ni I) at 361.9 nm (3d9(2D) 4p → 3d9(2D) 4s transition) reveals two peaks (fast and slow species) in short-pulse excitation and a single peak in ultrafast excitation. The fast and slow peaks represent recombined neutrals and un-ionized neutrals, respectively. TOF emission from singly ionized nickel (Ni II) studied using the 428.5 nm (3p63d8(3P) 4s→ 3p63d9 4s) transition shows only a single peak for either excitation. Velocities of the neutral and ionic species are determined from TOF measurements carried out at different positions (i.e., at distances of 2 mm and 4 mm, respectively, from the target surface) on the plume axis. Measured velocities indicate acceleration of neutrals and ions, which is caused by the Coulomb pull of the electrons enveloping the plume front in the case of ultrafast excitation. Both Coulomb pull and laser-plasma interaction contribute to the acceleration in the case of short-pulse excitation. These investigations provide new information on the pressure dependent temporal behavior of nickel plasmas produced by short-pulse and ultrafast laser pulses, which have potential uses in applications such as pulsed laser deposition and laser-induced nanoparticle generation.

  20. Electron transport and ion acoustic dynamics in laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Detering, Frank

    In this thesis laser-plasma processes are studied at transport and ion time scales. In order to study these processes the particle-in-cell code QN-PIC with one spatial dimension and three dimensions in velocity space was developed. Collisional effects are included by a Monte Carlo procedure, and an electric field solver based on the quasineutrality condition has been implemented. This allows long time scale simulations without having to resolve the electron plasma frequency. Collisional heating of the electrons in the laser electric field is one of the major restrictions on the time step in particle-in-cell codes. We have developed a collisional heating procedure that is based on a Langevin equation. It utilizes a Fokker-Planck equation that describes heating time averaged over the laser frequency. This procedure, in conjunction with the fast field solver and procedures to represent collisions, allows simulation of long time scale in laser-plasma interactions without the need to resolve the short time scales to ensure numerical stability and suppress numerical artifacts. We have studied in detail homogeneously heated plasmas and the effects of electron-electron collisions and collisional heating on the electron distribution function. We have suggested a nonlocal, nonlinear heat transport model based on a earlier self-consistent nonlocal transport theory that is formally restricted to small (linearized) temperature perturbations. Our model extends this model to the case of finite temperature perturbations. The model is tested successfully in simulations of hot spot relaxation of an initial temperature distribution that corresponds to the instantaneous release of heat into a spatially Gaussian temperature profile and Maxwellian velocity distributions of the electrons. In simulations of collisionally heated hot spots we qualitatively describe the effects of non-Maxwellian velocity distributions on the heat flux and the change of the distribution function due to transport in nonheated regions. For the representation of ion dynamics in QN-PIC we have conducted studies of the two stream instability with counterstreaming electrons and ions. Predicted growth rates of ion sound waves are recovered and we find it possible to study anomalous heating and resistivity in 1D ion sound turbulence. In laser plasmas ion sound turbulence due to the return current instability is thought to be one of the factors in the reduction of heat flux from hot spots. (Abstract shortened by UMI.)

  1. 7 CFR 1219.31 - Initial nomination and appointment of producer members and alternates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order The Hass Avocado Board § 1219.31 Initial nomination and appointment of...

  2. 7 CFR 1219.31 - Initial nomination and appointment of producer members and alternates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order The Hass Avocado Board § 1219.31 Initial nomination and appointment of...

  3. 7 CFR 1219.31 - Initial nomination and appointment of producer members and alternates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order The Hass Avocado Board § 1219.31 Initial nomination and appointment of...

  4. 7 CFR 1219.31 - Initial nomination and appointment of producer members and alternates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order The Hass Avocado Board § 1219.31 Initial nomination and appointment of...

  5. 7 CFR 1219.31 - Initial nomination and appointment of producer members and alternates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order The Hass Avocado Board § 1219.31 Initial nomination and appointment of...

  6. A Langmuir Probe Diagnostic for Use in Inhomogeneous, Time-Varying Plasmas Produced by High-Energy Laser Ablation

    SciTech Connect

    Patterson, J R; Emig, J A; Fournier, K B; Jenkins, P P; Trautz, K M; Seiler, S W; Davis, J F

    2012-05-01

    Langmuir probes (LP) are used extensively to characterize plasma environments produced by radio frequency, pulsed plasma thrusters, and laser ablation. We discuss here the development of a LP diagnostic to examine high-density, high-temperature inhomogeneous plasmas such as those that can be created at the University of Rochester's Laboratory for Laser Energetics OMEGA facility. We have configured our diagnostic to examine the velocity of the plasma expanding from the target. We observe velocities of approximately 16-17 cm/{micro}s, with individual LP currents displaying complex structures, perhaps due to the multiple atomic species and ionization states that exist.

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

    NASA Astrophysics Data System (ADS)

    Sizyuk, T.; Hassanein, A.

    2012-08-01

    Current challenges in the development of efficient laser produced plasma sources for the next generation extreme ultraviolet lithography (EUVL) are increasing EUV power and maximizing lifetime and therefore, reducing cost of devices. Mass-limited targets such as small tin droplets are considered among the best choices for cleaner operation of the optical system because of lower mass of atomic debris produced by the laser beam. The small diameter of droplets, however, decreases the conversion efficiency (CE) of EUV photons emission, especially in the case of CO2 laser, where laser wavelength has high reflectivity from the tin surface. We investigated ways of improving CE in mass-limited targets. We considered in our modeling various possible target phases and lasers configurations: from solid/liquid droplets subjected to laser beam energy with different intensities and laser wavelength to dual-beam lasers, i.e., a pre-pulse followed by a main pulse with adjusted delay time in between. We studied the dependence of vapor expansion rate, which can be produced as a result of droplet heating by pre-pulse laser energy, on target configuration, size, and laser beam parameters. As a consequence, we studied the influence of these conditions and parameters on the CE and debris mass accumulation. For better understanding and more accurate modeling of all physical processes occurred during various phases of laser beam/target interactions, plasma plume formation and evolution, EUV photons emission and collection, we have implemented in our heights package state-of-the art models and methods, verified, and benchmarked against laboratory experiments in our CMUXE center as well as various worldwide experimental results.

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

    SciTech Connect

    Sizyuk, T.; Hassanein, A.

    2012-08-15

    Current challenges in the development of efficient laser produced plasma sources for the next generation extreme ultraviolet lithography (EUVL) are increasing EUV power and maximizing lifetime and therefore, reducing cost of devices. Mass-limited targets such as small tin droplets are considered among the best choices for cleaner operation of the optical system because of lower mass of atomic debris produced by the laser beam. The small diameter of droplets, however, decreases the conversion efficiency (CE) of EUV photons emission, especially in the case of CO{sub 2} laser, where laser wavelength has high reflectivity from the tin surface. We investigated ways of improving CE in mass-limited targets. We considered in our modeling various possible target phases and lasers configurations: from solid/liquid droplets subjected to laser beam energy with different intensities and laser wavelength to dual-beam lasers, i.e., a pre-pulse followed by a main pulse with adjusted delay time in between. We studied the dependence of vapor expansion rate, which can be produced as a result of droplet heating by pre-pulse laser energy, on target configuration, size, and laser beam parameters. As a consequence, we studied the influence of these conditions and parameters on the CE and debris mass accumulation. For better understanding and more accurate modeling of all physical processes occurred during various phases of laser beam/target interactions, plasma plume formation and evolution, EUV photons emission and collection, we have implemented in our heights package state-of-the art models and methods, verified, and benchmarked against laboratory experiments in our CMUXE center as well as various worldwide experimental results.

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

    SciTech Connect

    Bame, S. J.; Phillips, J. L.; McComas, D. J.; Gosling, J. T.; Goldstein, B. E.

    1991-01-01

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

  10. Initial operation of a 10 ms, quasi-steady multi-megawatt, coaxial plasma thruster

    SciTech Connect

    Scheuer, J.T.; Schoenberg, K.F.; Henins, I.; Gerwin, R.A.; Garcia, J.A.; Gribble, R.F. ); Mayo, R.M.; Black, D.C. ); Hoyt, R.P. )

    1993-01-20

    The Los Alamos National Laboratory Coaxial Thruster Experiment (CTX) has been upgraded to enable the quasi-steady operation of MPD type thrusters at power levels from 1 to 40 MW for 10 ms. Initial diagnostics include an 8 position, 3 axis magnetic field probe to measure magnetic field fluctuations during the pulse, a triple Langmuir probe to measure ion density, electron temperature and plasma potential and a time-of-flight neutral particle spectrometer to measure specific impulse. Here we report on preliminary investigation of long-pulse quasi-steady coaxial thruster performance.

  11. Comparison of initial value and eigenvalue codes for kinetic toroidal plasma instabilities

    SciTech Connect

    Kotschenreuther, M.; Rewoldt, G.; Tang, W.M.

    1994-04-01

    In plasma physics, linear instability calculations can be implemented either as initial value calculations or as eigenvalue calculations. Here, comparisons between comprehensive linear gyrokinetic calculations employing the ballooning formalism for high-n (toroidal mode number) toroidal instabilities are described. One code implements an initial value calculation on a grid using a Lorentz collision operator and the other implements an eigenvalue calculation with basis functions using a Krook collision operator. An electrostatic test case with artificial parameters for the toroidal drift mode destabilized by the combined effects of trapped particles and an ion temperature gradient has been carefully analyzed both in the collisionless limit and with varying collisionality. Good agreement is found. Results from applied studies using parameters from the Tokamak Fusion Test Reactor (TFTR) experiment are also compared.

  12. Plasma Cell Neoplasm Manifesting Initially as a Sub-Cutaneous Supra-Orbital Swelling

    PubMed Central

    Jaiswal, Riddhi; Agarwal, Garima; Singh, Sudhir

    2016-01-01

    Multiple myeloma is a plasma cell neoplasm seen usually in patients over 50 years of age. Some cases may be asymptomatic initially and are detected during a routine test like complete blood count. They only require a close follow-up and monitoring. However, around 1% of these monoclonal gammopathy of undetermined significance progress to multiple myeloma every year and then they need to be taken care of by chemotherapy, targeted therapy, bisphosphonates and 6 monthly urine and bone examinations. Here, we present a case of 35-year-old female with an initial symptom of a vague backache along with a left subcutaneous supra-orbital swelling which was diagnosed as multiple myeloma by aspiration cytology and confirmed by ancillary tests. She has since been on treatment with bortezomib and prednisone and is responding well.

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

    NASA Astrophysics Data System (ADS)

    Hassanein, A.; Sizyuk, T.

    2013-05-01

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

  14. Schlieren-cinematographic and holographic diagnostic of a laser-produced plasma in xenon.

    PubMed

    Hugenschmidt, M; Vollrath, K; Hirth, A

    1972-02-01

    We have studied extensively a gas breakdown in xenon produced by a giant pulse ruby laser with a power <100 MW. Detailed information concerning the structure of the laser plasma formation and of the following expansion has been obtained by different optical methods, including schlieren techniques (single frames and ultra high speed cinematography) and holography. The high quality of the holographic pictures was achieved by the use of a monomode laser. With this we were able to visualize the plasma history and to determine the velocities of the boundary layer and of the blast wave with utmost accuracy. Investigations of the electron density and electron temperature showed that a relaxation time of about 10 nsec is necessary to establish local thermodynamic equilibrium states. After this relaxation time it is then possible to carry out thermodynamic calculations, applying the shock-wave theory, to relate the optically measured expansion velocity with the plasma parameters involved. The mean specific internal energy epsilon , for instance, attained values in excess of 10(12) erg/g which decayed rapidly during the first 100 nsec to about 5. 10(10) erg/g. By comparing the results to theoretical calculations of we obtained a first estimate of the temperature, taking into consideration the partial densities n(j) as well as the partition functions Z(j)((i)) of the xenon atoms, the single-charged ions, and the double-charged ones. Furthermore, a two-step iteration computer program was used to give more detailed and more accurate results on the variations of the pressure, temperature, partial densities, and enthalpy as a function of time. PMID:20111505

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Laser produced plasma sources for nanolithography—Recent integrated simulation and benchmarking

    SciTech Connect

    Hassanein, A.; Sizyuk, T.

    2013-05-15

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

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

    SciTech Connect

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

    2011-06-15

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

  18. Laboratory Magnetic Reconnection Experiments with Colliding, Magnetized Laser-Produced Plasma Plumes

    NASA Astrophysics Data System (ADS)

    Fox, W. R., II; Bhattacharjee, A.; Deng, W.; Moissard, C.; Germaschewski, K.; Fiksel, G.; Barnak, D.; Chang, P. Y.; Hu, S.; Nilson, P.

    2014-12-01

    We present results from experiments and simulations of magnetic reconnection between colliding plumes of laser-produced plasma. In the experiments, which open up a new experimental regime for reconnection study, bubbles of high-temperature, high-density plasma are created by focusing lasers down to sub-millimeter-scale spots on a plastic or metal foil, ionizing the foil into hemispherical bubbles that expand supersonically off the surface of the foil. If multiple bubbles are created at small separation, the bubbles expand into one another, and the embedded magnetic fields (either self-generated or externally imposed) are squeezed together and reconnect. We will review recent experiments, which have observed magnetic field annihilation, outflow jets, particle energization, and the formation of elongated current sheets. We compare the results against experiments with unmagnetized plumes, which observe the Weibel instability as the two plumes collide and interact. Particle-in-cell simulations of the strongly driven reconnection in these experiments show fast reconnection due to two-fluid effects, flux pile-up, and plasmoid formation, and show particle energization by reconnection.

  19. Gaussian energy distribution of fast ions emitted by laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Krsa, J.

    2013-05-01

    The analysis of ion collector signals with the use of a time-of-fight signal function derived from a shifted Maxwell-Boltzmann velocity distribution is used to quantify the ion characteristics as the ion temperature and velocity of centre-of-mass motion of groups of ionized species constituting the ablated plasma. The analysis is also focused on velocity and energy distributions derived from the signal of a time-of-flight detector taking into account the underlying principle of sensor operation. The energy Maxwell spectra of ions are compared with the Gauss distribution with respect to the ratio of the centre-of-mass energy of ions to their temperature. The difference threshold between the Gauss and energy Maxwell spectra is determined via the limited validity of the basic relationship between spreads in energy and time-of-flight spectra ?E/E = ?t/t. The analysis of velocity spectrum of fast ions emitted by Ti plasma produced with 300 ps, kJ-class iodine laser operating at PALS facility shows that ion bursts consist of almost monoenergetic ion beams.

  20. Preliminary study for producing higher harmonic hard x-rays from weakly ionized copper plasma

    NASA Astrophysics Data System (ADS)

    Sato, Eiichi; Hayasi, Yasuomi; Germer, Rudolf; Obara, Haruo; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Inoue, Takashi; Ogawa, Akira; Sato, Shigehiro; Takayama, Kazuyoshi; Ido, Hideaki

    2005-08-01

    In the plasma flash x-ray generator, a 200 nF condenser is charged up to 50 kV by a power supply, and flash x-rays are produced by the discharging. The x-ray tube is a demountable triode with a trigger electrode, and the turbomolecular pump evacuates air from the tube with a pressure of approximately 1 mPa. Target evaporation leads to the formation of weakly ionized linear plasma, consisting of copper ions and electrons, around the fine target, and intense K? lines are left using a 10-?m-thick nickel filter. At a charging voltage of 50 kV, the maximum tube voltage was almost equal to the charging voltage of the main condenser, and the peak current was about 16 kA. The K-series characteristic x-rays were clean and intense, and higher harmonic x-rays were observed. The x-ray pulse widths were approximately 300 ns, and the time-integrated x-ray intensity had a value of approximately 1.5 mGy per pulse at 1.0 m from the x-ray source with a charging voltage of 50 kV.

  1. Preliminary study for producing higher harmonic hard X-rays from weakly ionized nickel plasma

    NASA Astrophysics Data System (ADS)

    Sato, Eiichi; Hayasi, Yasuomi; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Inoue, Takashi; Ogawa, Akira; Sato, Shigehiro; Takayama, Kazuyoshi; Onagawa, Jun; Ido, Hideaki

    2006-11-01

    In the plasma flash X-ray generator, a 200 nF condenser is charged up to 50 kV by a power supply, and flash X-rays are produced by the discharging. The X-ray tube is a demountable triode with a trigger electrode, and the turbomolecular pump evacuates air from the tube with a pressure of approximately 1 mPa. Target evaporation leads to the formation of weakly ionized linear plasma, consisting of nickel ions and electrons, around the fine target, and intense K ? lines are left using a 15-?m-thick cobalt filter. At a charging voltage of 50 kV, the maximum tube voltage was almost equal to the charging voltage of the main condenser, and the peak current was about 18 kA. The K-series characteristic X-rays were clean and intense, and higher harmonic X-rays were observed. The X-ray pulse widths were approximately 300 ns, and the time-integrated X-ray intensity had a value of approximately 1.0 mGy at 1.0 m from the X-ray source with a charging voltage of 50 kV.

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

    SciTech Connect

    Farid, N.; Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian ; Harilal, S. S.; Hassanein, A.; Ding, H.

    2013-07-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-06-01

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

  4. Analysis of laser produced plasmas of gold in the 1-7 nm region

    NASA Astrophysics Data System (ADS)

    Li, Bowen; Higashiguchi, Takeshi; Otsuka, Takamitsu; Yugami, Noboru; Dunne, Padraig; Kilbane, Deirdre; Sokell, Emma; O'Sullivan, Gerry

    2014-04-01

    Extreme ultraviolet (EUV) spectra from gold laser produced plasmas were recorded in the 1-7 nm region using two Nd:YAG lasers with pulse lengths of 150 ps and 10 ns, respectively, operating at a range of power densities. The maximum focused peak power density was 9.5 1013 W cm-2 for the former and 5.3 1012 W cm-2 for the latter. Two intense quasicontinuous intensity bands resulting from n = 4-n = 4 and n = 4-n = 5 unresolved transition arrays dominate the 4-5.5 and 1.5-3.6 nm regions of both spectra. Comparison with atomic structure 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 ns spectrum, the highest ion stage that could be identified from the n = 4-n = 5 arrays was Au28+ while for the ps plasma the presence of significantly higher stages was deduced and lines due to 4d104f-4d94f2 transitions in Ag-like Au32+ give rise to the strongest observed features within the n = 4-n = 4 array while in the n = 4-n = 5 array it was possible to identify a number of previously unidentified spectral features as resulting from 4f-5g transitions in the spectra of Au XX to Au XXXIII.

  5. On the Rydberg transitions and elemental compositions in the laser produced Al (6063) plasma

    SciTech Connect

    Baig, M. A.; Fareed, M. A.; Rashid, B.; Ali, R.

    2011-08-15

    We present new studies on the optical emission spectra of the laser produced Al 6063 alloy plasma generated by the 1064 nm Nd: YAG laser. The spectrum reveals Rydberg transitions; nd {sup 2}D{sub 3/2,5/2}{yields} 3p {sup 2}P{sub 1/2,3/2} (n = 3 - 8), ns {sup 2}S{sub 1/2}{yields} 3p {sup 2}P{sub 1/2,3/2} (n 4-6), and the dominant spectral lines of the other constituent elements. We have extracted the relative abundance of the impurities using the relative intensity ratio method. Besides, we have calculated the electron temperature ({approx}7580 K) from the Boltzmann plot method and the electron number densities ({approx}1.4 x 10{sup 17}/cm{sup 3}) from the Stark widths of the aluminum spectral lines. The plasma parameters determined in the present work are in agreement with that reported in the literature. The molecular vibrational transitions of the AlO free radical associated with the B {sup 2}{Sigma}{yields}X {sup 2}{Sigma} band system have also been identified.

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

    SciTech Connect

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

    2012-05-15

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

  7. Diagnostics of Zinc-Selenium plasma produced by Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Hanif, M.; Salik, M.; Arif, F.

    2015-07-01

    We present the optical emission studies of the Zinc-Selenium (Zn-Se) plasma produced by the first (1064 nm) and second (532 nm) harmonics of a Q-switched Nd:YAG laser. The target material was placed in front of laser beam in air at atmospheric pressure. The experimentally observed line profiles of neutral zinc (Zn I) at 249.34, 256.77, 271.24 and 277.09 nm respectively have been used to extract the electron temperature using the Boltzmann plot method. Whereas, the electron number density has been determined from the Stark broadening method using the neutral zinc (Zn I) line at 481.05 nm. The electron temperature is calculated by varying the distance from the target surface along the line of propagation of plasma plume and also by varying the laser irradiance. Beside we have studied the variation of number density as a function of laser irradiance as well as its variation with distance from the target surface. It is observed that electron temperature and electron number density increases as laser energy is increased.

  8. Potential effects of Plasma on the Development of Laser Produced Craters

    SciTech Connect

    Batani, Dimitri; Desai, Tara; Rossetti, Stefano; Lucchini, Gianni

    2006-04-07

    Laser ablation and crater formation have been studied on a copper target using a 10 Hz, Nd:YAG laser system delivering pulses up to 100 mJ in 40 ps with a flux on target F{<=} 5000 J/cm2. Crater dimensions were measured using optical microscope or SEM (Scanning Electron Microscope). In order to understand the process of crater formation, we considered various theoretical models present in the literature and revised them taking into account the occurrence of plasma phenomena, which are important at the intensities used in this experiment. We also compared our experimental results with other results obtained at the PALS laboratory, using a 0.44 {mu}m wavelength laser and much higher laser intensities. Finally we explore the possibility of extending the information derived from laser produced craters to other types of craters.

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

    NASA Technical Reports Server (NTRS)

    Hollahan, J. R.; Wydeven, T.

    1975-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  11. Extreme ultraviolet light sources and soft x-ray laser based on discharge produced plasma

    NASA Astrophysics Data System (ADS)

    Hotta, Eiki; Sakai, Yusuke; Hayashi, Yasushi; Niimi, Gohta; Huang, Bin; Zhu, Qiushi; Song, Inho; Watanabe, Masato

    2015-07-01

    Due to the demand to realize shorter wavelength light sources, extreme ultraviolet (EUV) sources and soft x-ray laser (SXRL) are under development. The development of EUV sources at the wavelength of 13.5 nm started to realize light sources to be used for next generation lithography. Xenon was used at the beginning of development, however, to attain higher conversion efficiency, tin is now used as fuel. As a coherent light source, capillary discharge SXRL is under development. After the demonstration of Ne-like Ar SXRL by using electron collisional excitation scheme, the effort to shorten the wavelength has been made by adopting recombination scheme such as H-like N. Though the challenge has not yet been successful, the source has potential to be used as a SXR source in the water window wavelength region. Current status of EUV and SXR sources based on discharge produced plasma will be given.

  12. Spectroscopic characterization of plane multilayer diffraction gratings using a laser-produced plasma XUV radiation source

    NASA Astrophysics Data System (ADS)

    Kolachevsky, Nikolai N.; Mitropolsky, Mikhail M.; Ragozin, Eugene N.; Bac, S.; Troussel, Philippe

    1998-06-01

    Spectral characteristics of plane multilayer amplitude molybdenum-silicon diffraction gratings (1000 and 2000 lines/mm, d-spacing of 115 angstrom), fabricated by electron- beam lithography, were determined using a laser-produced plasma XUV radiation source. The gratings were studied at near-normal incidence and at an angle of incidence of 36 degrees in stigmatic and quasi-stigmatic spectrograph systems with moderate dispersion. The task of focusing radiation was imposed on either a grazing-incidence toroidal mirror or a normal-incidence Mo-Si multilayer mirror with a d-spacing of 115 angstrom. The spectral profile of resonance reflection by the gratings was determined in the first and second Bragg orders of the multilayer structure for different angles of incidence. Line spectra of multiply charged F, Na, Mg, and Cl ions were recorded in the 160 - 230 angstrom range by means of these multilayer gratings, and the resolving power of the gratings was determined.

  13. Elliptically-bent crystal spectrograph for X-ray diagnosis of laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Xiong, Xiancai; Zhong, Xianxin; Xiao, Shali; Yang, Guohong; Gao, Jie

    2004-01-01

    In order to measure spatially and temporarily resolved laser-produced plasma X-ray spectra in 0.2-2 nm region, a novel two-channel elliptically-bent crystal spectrograph has been developed. Dispersive elements are LiF, PET, Mica, and KAP crystals, which cover Bragg angles in the range of 30-67.5 degrees. Eccentricity and focal distance of twin ellipses are 0.9586 and 1350 mm, respectively. Spatially resolved spectrum is photographically recorded with an X-ray film or X-CCD camera in one channel, and temporarily resolved one is photographically recorded with an X-ray streak camera in another channel, thus spatially and temporarily resolved spectra can be simultaneously obtained. Spectral images were acquired with X-CCD and PET in SHENGUANG-II laser facility, and experimental results show that the spectral resolution of the spectrograph is about 0.002 nm.

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

    SciTech Connect

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

    2012-10-15

    The volumetric heating of a thin copper target has been studied with time resolved x-ray spectroscopy. The copper target was heated by a plasma produced using the Lawrence Livermore National Laboratory's Compact Multipulse Terawatt (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 two-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.

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

    SciTech Connect

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

    2015-03-15

    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.

  16. Calibration of a Flat Field Soft X-ray Grating Spectrometer for Laser Produced Plasmas

    SciTech Connect

    Park, J; Brown, G V; Schneider, M B; Baldis, H A; Beiersdorfer, P; Cone, K V; Kelley, R L; Kilbourne, C A; Magee, E; May, M J; Porter, F S

    2010-05-12

    We have calibrated the x ray response of a variable line spaced grating spectrometer, known as the VSG, at the Fusion and Astrophysics Data and Diagnostic Calibration Facility at the Lawrence Livermore National Laboratory (LLNL). The VSG has been developed to diagnose laser produced plasmas, such as those created at the Jupiter Laser Facility and the National Ignition Facility at LLNL, and at both the Omega and Omega EP lasers at University of Rochester's Laboratory for Laser Energetics. The bandwidth of the VSG spans the range from {approx} 6 to 60 {angstrom}. The calibration results present here include the VSG's dispersion and quantum efficiency. The dispersion is determined by measuring the x rays emitted from hydrogen-like and helium-like ions of carbon, nitrogen, oxygen, neon, and aluminum. The quantum efficiency is calibrated to an accuracy of 30% or better by normalizing the x ray intensities recorded by the VSG to those simultaneously recorded by an x ray microcalorimeter spectrometer.

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

    SciTech Connect

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

    2012-05-02

    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.

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

    DOEpatents

    Renard-Le Galloudec, Nathalie (Reno, NV); Cowan, Thomas E. (Reno, NV); Sentoku, Yasuhiko (Reno, NV); Rassuchine, Jennifer (Reno, NV)

    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.

  19. Magnetic properties of Co-Zr-B magnets produced by spark plasma sintering method

    SciTech Connect

    Saito, Tetsuji Akiyama, Tomoya

    2014-05-07

    Magnets of Co-Zr-B, one of the permanent magnetic compounds without rare-earth elements, were successfully produced by the spark plasma sintering method. The resultant Co-Zr-B magnets had high densities of 92%–96% and consisted mainly of the Co{sub x}Zr (x ≈ 5) phase. The coercivity of the Co-Zr-B magnets was highly dependent on the consolidation temperature and the boron content. The highest maximum energy product of 6.0 MGOe, with a remanence of 6.4 kG and the coercivity of 4.0 kOe, was achieved by the Co{sub 80}Zr{sub 18}B{sub 2} magnets consolidated at 873 K.

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

    PubMed

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

    2012-10-01

    The volumetric heating of a thin copper target has been studied with time resolved x-ray spectroscopy. The copper target was heated by a plasma produced using the Lawrence Livermore National Laboratory's Compact Multipulse Terawatt (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 two-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. PMID:23126959

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

    PubMed

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

    2015-03-01

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

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Features in the ion emission of Cu, Al, and C plasmas produced by ultrafast laser ablation

    NASA Astrophysics Data System (ADS)

    Kelly, T. J.; Butler, T.; Walsh, N.; Hayden, P.; Costello, J. T.

    2015-12-01

    The bi-modal nature of charge integrated ion kinetic energy distributions, which result from ultrafast laser produced plasmas, is discussed in this paper. A negatively biased Faraday cup was used as a charge collector to measure ion distributions from three different solid targets that had been irradiated with an ultrafast laser in the fluence range 0.1 -1 J/cm 2 . A bi-modal time of flight distribution is found for all three targets (C, Al, and Cu). In the case of the metallic targets (Al and Cu), high- and low-kinetic energy peaks exhibit quite different dependencies on laser fluence, whereas for the semi-metallic target (C), both peaks scale similarly with ultrafast laser fluence. The results are discussed within the framework of a one dimensional capacitor model resulting in ion acceleration.

  4. Residual-current excitation in plasmas produced by few-cycle laser pulses.

    PubMed

    Silaev, A A; Vvedenskii, N V

    2009-03-20

    Along with the generation of extreme-ultraviolet and soft x-ray radiation, gas ionization by an intense few-cycle laser pulse can also induce the generation of low-frequency terahertz waves. The latter is caused by the excitation of a residual quasi-dc current in the produced plasma by the electric field of the laser pulse. We describe this phenomenon using the quantum-mechanical approach based on solving the 3D time-dependent Schrödinger equation. We calculate the dependences of the residual-current density on the carrier-envelope phase, duration, and intensity of the few-cycle laser pulse, and find optimal conditions for high-efficiency realization of the studied phenomenon. PMID:19392210

  5. Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Shi, Jun; Xiao, Sha-Li; Wang, Hong-Jian; Tang, Chang-Huan; Liu, Shen-Ye

    2008-07-01

    In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X-ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal (200) (2 d = 0.4027 nm) is used as dispersive element covering Bragg angle from 30 to 67.5. The spectrometer was tested on Shenguang-II which can deliver laser energy of 60 80 J/pulse and the laser wavelength is 0.35 ?m. Photographs of spectra including the 1s2p 1P1-1s2 1S0 resonance line( w), the 1s2p 3P2-1s2 1S0 magnetic quadrupole line( x), the 1s2p 3P1-1s2 1S0 intercombination lines( y), the 1s2p 3S1-1s2 1S0 forbidden line( z) in helium-like Ti X XI and the 1s2s2p 2P3/2-1s22s 2S1/2 line( q) in lithium-like Ti X X have been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution( ?/??) is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.

  6. Study of Ozone-Initiated Limonene Reaction Products by Low Temperature Plasma Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Nrgaard, Asger W.; Vibenholt, Anni; Benassi, Mario; Clausen, Per Axel; Wolkoff, Peder

    2013-07-01

    Limonene and its ozone-initiated reaction products were investigated in situ by low temperature plasma (LTP) ionization quadrupole time-of-flight (QTOF) mass spectrometry. Helium was used as discharge gas and the protruding plasma generated ~850 ppb ozone in front of the glass tube by reaction with the ambient oxygen. Limonene applied to filter paper was placed in front of the LTP afterglow and the MS inlet. Instantly, a wide range of reaction products appeared, ranging from m/ z 139 to ca. 1000 in the positive mode and m/ z 115 to ca. 600 in the negative mode. Key monomeric oxidation products including levulinic acid, 4-acetyl-1-methylcyclohexene, limonene oxide, 3-isopropenyl-6-oxo-heptanal, and the secondary ozonide of limonene could be identified by collision-induced dissociation. Oligomeric products ranged from the nonoxidized dimer of limonene (C20H30) and up to the hexamer with 10 oxygen atoms (C60H90O10). The use of LTP for in situ ozonolysis and ionization represents a new and versatile approach for the assessment of ozone-initiated terpene chemistry.

  7. Physical and chemical properties of dust produced in a N{sub 2}-CH{sub 4} RF plasma discharge

    SciTech Connect

    Ouni, F.; Alcouffe, G.; Szopa, C.; Carrasco, N.; Cernogora, G.; Adande, G.; Thissen, R.; Quirico, E.; Brissaud, O.; Schmitz-Afonso, I.; Laprevote, O.

    2008-09-07

    Titan's atmospheric chemistry is simulated using a Capacitively Coupled Plasma discharge produced in a N{sub 2}-CH{sub 4} mixture. The produced solid particles are analysed ex-situ. Chemical properties are deduced from: elemental composition, FTIR and LTQ-Orbitrap mass spectrometer. Optical properties are deduced from reflectivity in visible and IR range.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    A multipoint Thomson scattering diagnostic has recently been installed on the Pegasus ST. The system utilizes a frequency-doubled Nd:YAG laser (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.

  9. Structure and properties of commercially pure titanium nitrided in the plasma of a low-pressure gas discharge produced by a PINK plasma generator

    NASA Astrophysics Data System (ADS)

    Ivanov, Yu F.; Akhmadeev, Yu H.; Lopatin, I. V.; Petrikova, E. A.; Krysina, V.; Koval, N. N.

    2015-11-01

    The paper analyzes the surface structure and properties of commercially pure VT1-0 titanium nitrided in the plasma of a low-pressure gas discharge produced by a PINK plasma generator. The analysis demonstrates that the friction coefficient of the nitrided material decreases more than four times and its wear resistance and microhardness increases more than eight and three times, respectively. The physical mechanisms responsible for the enhancement of strength and tribological properties of the material are discussed.

  10. Laser Produced Plasmas as a Source of Ions, Protons and X-rays

    NASA Astrophysics Data System (ADS)

    Stefanuik, Robert

    The work presented in this thesis is primarily focused on the use of a laser produced plasma as a source of protons, ions and X-rays. It explores high impact applications of both high power ultrafast lasers and nanosecond lasers. Section 1 gives a general introduction to the physics governing the experiments and the lasers in the following sections. Section 2 describes all the laser systems used in this thesis. Section 3 is covers two different experiments involving the generation of X-rays from a laser produced plasma. Section 4 describes a laser accelerated proton experiment conducted in the Center for Plasma Research in Queens University Belfast, using the TARANIS laser system. In this experiment 13 MeV protons were accelerated from10 ?m gold foil targets into a sample of BK-7 glass. The interaction of the protons with the glass were observed by taking spatially resolved images of the transient opacity induced by the protons interacting with the BK-7 Glass and an optical probe beam. These spatially resolved images are presented in Section 4.3. Section 5 describes the refurbishment of the 1-m normal incidence VUV spectrometer. It describes the replacement of a photographic plate based detection system with a linear CCD array. The CCD array can detect the VUV radiation through a sodium salicylate phosphor coating which emits at 410 nm on interacting with VUV radiation. Different phosphors are compared in terms of sensitivity and ease of coating and the grounds for choosing sodium salicylate are explained. The adaptations to the spectrometer to use the linear CCD array are described and the details on calibrating the spectrometer are explained. Finally, Section 6 describes a set of spectroscopic experiments which use the refurbished 1-m normal incidence spectrometer. First Section 6.2 describes a repeat of the photoabsorption of indium and indium plus which was conducted previously on the spectrometer. This was designed as a proof of principle of the working of the new phosphor based linear CCD array system. (Abstract shortened by UMI.).

  11. Characterization of Laser-Produced Plasmas for Extreme Ultraviolet and Soft X-Ray Sources

    NASA Astrophysics Data System (ADS)

    Kambali, Imam

    The wide range of applications of extreme ultraviolet (EUV) and soft X-ray sources including for next generation photolithography around 13.5 nm and 6.7 nm as well as for broadband EUV sources lead to the investigations of various methods to generate the radiation. In this thesis, spectral emission from laser-produced plasmas (LPPs) of several target materials such as tin, tin-gold alloy, tin-lead alloy, galinstan and gadolinium for EUV sources has been theoretically and experimentally characterized. LPPs of pure tin targets show very bright EUV emission around 13.5 nm whereas LPPs of Gd targets show unresolved transition arrays (UTAs) near 6.7 nm. Alloy targets such as Sn-Au, Sn-Pb and galinstan give rise to a broadband EUV emission in the 10 - 18 nm regions, though the most intense radiation remains observed around 13.5 nm. The temporal behavior of Sn, Sn-Au and Sn-Pb alloys as well as Gd closely matches the temporal profile of the Nd:YAG laser used in the experiments. This thesis is divided into 9 Chapters. The theoretical background and motivations of this PhD work are presented in Chapter 1, whereas the experimental apparatus is described in Chapter 2. Chapter 3 discusses the theoretical calculations of the EUV and soft X-ray emission from several atomic elements including tin (Sn), gold (Au), lead (Pb), gallium (Ga), indium (In) as well as gadolinium (Gd) using the Cowan codes. Various steady state plasma calculations performed using the Colombant and Tonon model are also presented in Chapter 3. Spectral analysis of EUV emission from laser produced plasmas (LPPs) of Sn, Au and Sn-Au along with their conversion efficiencies (CEs) are compared in Chapter 4, whereas a galinstan LPP is highlighted in Chapter 5 as a promising EUV source around 13.5 nm based on its spectral behaviour at different laser fluxes and spot sizes. In the last three results and discussion chapters (Chapters 6-8), the temporal evolution of several material targets including Sn, Sn-Au, Sn-Pb and gadolinium is presented. Eventually Chapter 9 concludes the whole work.

  12. Microstructure of the nitride layer of AISI 316 stainless steel produced by intensified plasma assisted processing

    NASA Astrophysics Data System (ADS)

    Jiang, J. C.; Meletis, E. I.

    2000-10-01

    Nitrided austenitic 316 stainless steel produced by intensified plasma assisted processing has been studied by transmission electron microscopy (TEM), high-resolution TEM, and image simulation techniques. Cross-sectional TEM studies showed that the nitride layer is composed of a single phase that was found to possess a simple cubic structure. This nitride is produced by introducing one N atom into one of the interstitial sites of the octahedra within the unit cell of the γ-austenite. The lattice constant of the nitrided simple cubic structure was determined to be a=3.78 Å, which is expanded by about 5.4% from that of austenite. Stacking faults, antiphase domains, and antiphase domain boundaries in the nitride layer were observed using dark-field and high-resolution TEM imaging. The evolution of the nitride phase seems to be preceded by lattice expansion and formation of stacking faults due to the presence of N and is consistent with the observed lattice constant reduction with depth.

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2014-09-01

    We analyzed embryo culture medium (CM) and recipient blood plasma using Fourier transform infrared (FTIR) metabolomics to predict pregnancy outcome. Individually cultured, in vitro-produced (IVP) blastocysts were transferred to recipients as fresh and vitrified-warmed. Spent CM and plasma samples were evaluated using FTIR. The discrimination capability of the classifiers was assessed for accuracy, sensitivity (pregnancy), specificity (nonpregnancy), and area under the receiver operator characteristic curve (AUC). Within all IVP fresh embryos (birth rate=52%), high AUC were obtained at birth, especially with expanded blastocysts (CM: 0.800.053; plasma: 0.890.034). The AUC of vitrified IVP embryos (birth rate = 31%) were 0.6070.038 (CM, expanded blastocysts) and 0.6720.023 (plasma, all stages). Recipient plasma generally predicted pregnancy outcome better than did embryo CM. Embryos and recipients with improved pregnancy viability were identified, which could increase the economic benefit to the breeding industry. PMID:24997663

  15. Time-resolved extreme-ultraviolet spectroscopy of laser-produced plasmas originating at the parylene layer of microballon targets

    SciTech Connect

    Griem, H.R.; Moreno, J.

    1991-03-01

    In experiments this past year at the University of Rochester's Laboratory for Laser Energetics we obtained time-integrated and time-resolved spectra from the ultraviolet to the x-ray region. We have investigated various phenomena in laser-produced plasmas including spectral line broadening, plasma expansion velocities, ionization and recombination of low-Z materials in spherical targets, and the formation of satellites near some resonance lines. In addition we have improved our spectroscopic instrumentation.

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

    DOEpatents

    Sher, Mark H. (Los Altos, CA); Macklin, John J. (Stanford, CA); Harris, Stephen E. (Palo Alto, CA)

    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.

  17. Increasing Stabilized Performance Of Amorphous Silicon Based Devices Produced By Highly Hydrogen Diluted Lower Temperature Plasma Deposition.

    DOEpatents

    Li, Yaun-Min (Langhorne, PA); Bennett, Murray S. (Langhorne, PA); Yang, Liyou (Plainsboro, NJ)

    1999-08-24

    High quality, stable photovoltaic and electronic amorphous silicon devices which effectively resist light-induced degradation and current-induced degradation, are produced by a special plasma deposition process. Powerful, efficient single and multi-junction solar cells with high open circuit voltages and fill factors and with wider bandgaps, can be economically fabricated by the special plasma deposition process. The preferred process includes relatively low temperature, high pressure, glow discharge of silane in the presence of a high concentration of hydrogen gas.

  18. Increased Stabilized Performance Of Amorphous Silicon Based Devices Produced By Highly Hydrogen Diluted Lower Temperature Plasma Deposition.

    DOEpatents

    Li, Yaun-Min (Langhorne, PA); Bennett, Murray S. (Langhorne, PA); Yang, Liyou (Plainsboro, NJ)

    1997-07-08

    High quality, stable photovoltaic and electronic amorphous silicon devices which effectively resist light-induced degradation and current-induced degradation, are produced by a special plasma deposition process. Powerful, efficient single and multi-junction solar cells with high open circuit voltages and fill factors and with wider bandgaps, can be economically fabricated by the special plasma deposition process. The preferred process includes relatively low temperature, high pressure, glow discharge of silane in the presence of a high concentration of hydrogen gas.

  19. Influence of corundum structure on the characteristics of multiply charged ions in a laser-produced plasma

    SciTech Connect

    Bedilov, M R; Beisembaeva, Kh B; Sabitov, M S

    2000-01-31

    An investigation was made of the interaction of intense laser radiation ({lambda} = 1.06 {mu}m) with previously irradiated corundum. The studies were performed in the collecting mode by employing time-of-flight mass spectrometry. Electron and ion currents were considered simultaneously with charge-state and energy characteristics of multiply charged ions of the plasmas produced at the source and previously irradiated targets. The combined consideration allows the conclusion that the prior neutron irradiation of a sample by a fluence of 10{sup 15} - 10{sup 19} neutron cm{sup -2} makes for production of a higher-temperature plasma. (interaction of laser radiation with matter. laser plasma)

  20. Large-Scale Filamentary Structures in Laser-Produced Plasmas as a Sign of Strong Magnetic Field Generation

    NASA Astrophysics Data System (ADS)

    Kukushkin, A. B.; Rantsev-Kartinov, V. A.

    1998-11-01

    The method [1] of multilevel dynamical contrasting is applied to available database from experiments on interaction of a powerful short-pulsed laser beam with a flat target. It was found from processing the soft X-ray images that the expanding plasma produces a dynamical filamentary structures, a long-living ones as compared to inertial lifetimes of plasma inhomogeneities in laser-produced plasmas. Such a structuring appears to be similar to the networking of filamented electric currents in high-current gaseous discharges (dense Z-pinch [1] and plasma focus [2]). The structuring disclosed suggests a view into the role of electric current filamentation in the following phenomena in laser-produced plasmas: (i) generation of a strong magnetic field by the strong filamentary electric currents; (ii) formation of closed electric currents and large-scale closed magnetic configurations; (iii) axial stratification of the emerging dense Z-pinch; (iv) formation of long-range bonds between the core and the periphery of expanding plasma. [1] Kukushkin A.B., Rantsev-Kartinov V.A., Laser and Particle Beams, 16(3) 1998 (to be published). [2] Kukushkin A.B., Rantsev-Kartinov V.A., Terentiev A.R., Fusion Technology, 32 (1997) 83.

  1. Study of ultra-intense laser produced plasmas via computer simulation

    NASA Astrophysics Data System (ADS)

    Chrisman, Brian R.

    Recent advances in the development of intense short pulse lasers have led to exciting progress in high energy density physics (HEDP). As an example, a several mum thin foil that is irradiated by a 100 TW, sub-picosecond laser pulse reaches keV (1 keV 11,000,000 C) temperatures at solid density. The resultant electron distribution is temporarily far out of equilibrium, featuring two or more widely distinct temperatures. In modeling such extreme plasmas, both kinetic and collisional effects on the energy transport are essential. Of particular difficulty are the large density gradients between the critical density (the density at which the laser is absorbed), and solid densities exceeding several hundred times the critical density. For a 1 mum wavelength laser pulse, the critical density, nc, is 1021 cm --3. This means that a numerical model needs to describe the laser-plasma interaction in the low density region, as well as fast particle transport in the extremely dense target region where Coulomb collision processes are important for energy transfer. In cone-guided fast ignition inertial confinement fusion experiments, fuel previously compressed by an ablative implosion is ignited by the injection of an intense short laser pulse via a cone embedded within the fuel target. The implosion precondition creates density scales which range over five orders of magnitude from the cone interior to the highly compressed core. A critical issue for this process is whether the hot electrons produced in the interaction are in an energy range conducive to efficient heating of the core. In this work, Particle-in-Cell simulations evaluate the entire cone-guided fast ignition experiment for the first time, including hot electron generation at the cone tip, energy transport to the compressed fuel core, and subsequent collisional core heating. The laser-plasma interaction within the cone target is particularly important, as temperatures of hot electrons generated here are found to be lower than previously expected while overall absorption is influenced by non-linear electrodynamic processes.

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  3. Solid oxide fuel cell electrolytes produced by a combination of suspension plasma spray and very low pressure plasma spray.

    SciTech Connect

    Slamovich, Elliot; Fleetwood, James; McCloskey, James F.; Hall, Aaron Christopher; Trice, Rodney Wayne

    2010-07-01

    Plasma spray coating techniques allow unique control of electrolyte microstructures and properties as well as facilitating deposition on complex surfaces. This can enable significantly improved solid oxide fuel cells (SOFCs), including non-planar designs. SOFCs are promising because they directly convert the oxidization of fuel into electrical energy. However, electrolytes deposited using conventional plasma spray are porous and often greater than 50 microns thick. One solution to form dense, thin electrolytes of ideal composition for SOFCs is to combine suspension plasma spray (SPS) with very low pressure plasma spray (VLPPS). Increased compositional control is achieved due to dissolved dopant compounds in the suspension that are incorporated into the coating during plasma spraying. Thus, it is possible to change the chemistry of the feed stock during deposition. In the work reported, suspensions of sub-micron diameter 8 mol.% Y2O3-ZrO2 (YSZ) powders were sprayed on NiO-YSZ anodes at Sandia National Laboratories (SNL) Thermal Spray Research Laboratory (TSRL). These coatings were compared to the same suspensions doped with scandium nitrate at 3 to 8 mol%. The pressure in the chamber was 2.4 torr and the plasma was formed from a combination of argon and hydrogen gases. The resultant electrolytes were well adhered to the anode substrates and were approximately 10 microns thick. The microstructure of the resultant electrolytes will be reported as well as the electrolyte performance as part of a SOFC system via potentiodynamic testing and impedance spectroscopy.

  4. Theory and three-dimensional simulation of light filamentation in laser-produced plasma

    SciTech Connect

    Berger, R.L.; Lasinski, B.F.; Kaiser, T.B.; Williams, E.A.; Langdon, A.B.; Cohen, B.I. )

    1993-07-01

    A desire to interpret recent experiments on filamentation with and without beam-smoothing techniques led to the development of a three-dimensional fluid model that includes the effects of nonlocal electron transport and kinetic ion damping of the acoustic waves. The damping of the electron-temperature perturbations that drive thermal filamentation by nonlocal electron conduction, valid in the diffusive limit, is supplemented in the present model by electron Landau damping in the collisionless limit when the wavelength of the perturbation is much less than the electron--ion scattering mean-free path. In this collisionless limit, Landau damping of the temperature'' fluctuations makes ponderomotive forces universally more important than thermal forces. Simulations in plasmas of current interest illustrate the relative importance of thermal and ponderomotive forces for strongly modulated laser beams. Although thermal forces may initiate filamentation, the most intense filaments are associated with ponderomotive forces. The present simulations of filamentation model well the density perturbations observed in experiments [Young [ital et] [ital al]., Phys. Rev. Lett. [bold 61], 2336 (1988)]. In addition, a simple criterion is obtained analytically and supported by simulations for stabilization of filamentation by laser beam-smoothing techniques such as induced spatial incoherence and random phase plates [Eq. (1)].

  5. Optical transmission and reflection of a plasma produced in nanosecond laser induced air breakdown

    NASA Astrophysics Data System (ADS)

    Mahdieh, M. H.; Akbari J., M.; Bababei, Z.

    2015-02-01

    In this paper, we investigate dynamics of optical breakdown in air induced by a pump- probe laser beam technique. The optical breakdown was generated by an Nd:YAG laser beam (operating at 10 ns pulse duration and 1064 nm wavelength). A small part of the beam was separated from the main beam by an optical splitter and was aligned to probe the breakdown plasma transversely. Monitoring the time resolved reflectivity from the breakdown plasma may give information on critical density and together with its transmittivity through the plasma provides information on plasma absorptivity. The results of this experiment can be also used to describe dynamics of breakdown plasma evolution.

  6. Measurements of electron density and temperature profiles in plasma produced by Nike KrF laser for laser plasma instability research

    NASA Astrophysics Data System (ADS)

    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 (? = 263 nm, ?t = 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 ?m 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. Development of a collective Thomson scattering system for laser-produced tin plasmas for extreme-ultraviolet light sources

    NASA Astrophysics Data System (ADS)

    Tomita, Kentaro; Sato, Yuta; Nishikawa, Kazutaka; Uchino, Kiichiro; Yanagida, Tatsuya; Tomuro, Hiroaki; Wada, Yasunori; Kunishima, Masahito; Kodama, Takeshi; Mizoguchi, Hakaru; Sunahara, Atsushi

    2015-12-01

    Spatial profiles of electron density (ne) and electron temperature (Te) of laser-produced Sn plasmas for extreme-ultraviolet (EUV) light sources have been obtained using a new collective Thomson scattering system, which has been optimized for the measurement of the ion feature spectrum. The system has an 18 pm spectral resolution, a 5 ns temporal resolution, a 50 m spatial resolution, and sufficient stray-light rejection near the probing laser wavelength. With this system, measurements of the laser-produced Sn plasmas in the parameter ranges of 3 1023 < ne < 1025 m?3 and 10 < Te < 20 eV have been performed.

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

    SciTech Connect

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

    1987-08-01

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

  9. Aqueous-Based Latex Systems for Producing Durable Waste Forms-Initial Characterization

    SciTech Connect

    Terry, Troy N.; Russell, Renee L. ); Smith, Harry D. ); Liang, Liang ); Smith, Gary L. )

    2000-11-01

    The overall objective of this project is to identify and successfully demonstrate a water-based polyceram system suitable for producing an environmentally stable waste form highly loaded with salt wastes. The backbone for this idea is the development of aqueous based sol-gel technology. Most interest in sol-gel synthesis of ceramics in recent years has concentrated on the hydrolysis of metal alkoxides in organic media, but the alternative sol-gel process in aqueous media may offer acceptable results without the need for hazardous precursors or waste products. To accomplish this, water micelle (like an emulsion) systems will be substituted for the organic based systems already identified. Preliminary tests show that emulsions such as Styrene/Butadiene and Acrylic latex are good candidates for the aqueous media. Both of these materials when mixed with a percentage of natural latex have been shown to effectively immobilize salt wastes with loadings over 10 wt%. The low cost, availability, and ease of preparation (low temperature of cure) of these products makes them strong contenders as a waste form. Techniques for improving both chemical and physical properties, such as adding cross-linking agents and fine-tuning the curing process, are currently in development at Pacific Northwest National Laboratories along with collaboration with staff from the University of Arizona.

  10. Initial experimental results from a laboratory size beam plasma discharge device

    NASA Technical Reports Server (NTRS)

    Konradi, A.; Bernstein, W.; Bulgher, D. L.; Garrity, J. O.; Winkler, J. L.

    1983-01-01

    A laboratory beam plasma discharge (BPD) device produced BPD in N2, A, and He. All features of the BPD observed in the device agree with those observed in a large vacuum chamber. The empirical ignition criteria determined in the large chamber apply in the small device but do not fit when used for extrapolation between the large and the small geometry. At some energies and magnetic fields beam currents exist for which the total light output in the BPD state varies by a factor of 2 with a factor of 6 pressure variation. Above 0.0001 torr the BPD width is pressure independent but for lower pressures it expands by as much as a factor of 4 at 0.00002 torr.

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

    SciTech Connect

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

    2008-05-11

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

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

    PubMed

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

    2008-10-01

    The Electron Beam Ion Trap (EBIT) facility at the Lawrence Livermore National Laboratory is being used to absolutely calibrate the transmission efficiency of x-ray filters employed by diodes and spectrometers used to diagnose laser-produced plasmas. EBIT emits strong, discrete monoenergetic lines at appropriately chosen x-ray energies. X rays are detected using the high resolution EBIT Calorimeter Spectrometer (ECS), developed for LLNL at the NASA/Goddard Space Flight Center. X-ray filter transmission efficiency is determined by dividing the x-ray counts detected when the filter is in the line of sight by those detected when out of the line of sight. Verification of filter thickness can be completed in only a few hours, and absolute efficiencies can be calibrated in a single day over a broad range from about 0.1 to 15 keV. The EBIT calibration lab has been used to field diagnostics (e.g., the OZSPEC instrument) with fully calibrated x-ray filters at the OMEGA laser. Extensions to use the capability for calibrating filter transmission for the DANTE instrument on the National Ignition Facility are discussed. PMID:19044471

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

    SciTech Connect

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

    2013-10-15

    Laser target energy coupling mechanism is crucial in the shock ignition (SI) scheme, and x-ray radiation energy is a non-negligible portion of the laser produced plasma energy. To evaluate the x-ray radiation energy amount at conditions relevant to SI scheme, instantaneous x-ray radiation energy is investigated experimentally with continuum phase plates smoothed lasers irradiating layer polystyrene targets. Comparative laser pulses without and with shock spike are employed. With the measured x-ray angular distribution, full space x-ray radiation energy and conversion efficiency are observed. Instantaneous scaling law of x-ray conversion efficiency is obtained as a function of laser intensity and time. It should be pointed out that the scaling law is available for any laser pulse shape and intensity, with which irradiates polystyrene planar target with intensity from 2 × 10{sup 14} to 1.8 × 10{sup 15} W/cm{sup 2}. Numerical analysis of the laser energy transformation is performed, and the simulation results agree with the experimental data.

  14. Treatment of phenol wastewater using hydroxyl radical produced by micro-gap discharge plasma technique.

    PubMed

    Yang, Xianli; Bai, Mindong; Han, Fen

    2009-04-01

    Hydroxyl radical produced by non-equilibrium plasma, which was induced by micro-gap dielectric barrier discharge, was used for the treatment of phenol wastewater. The advantage of this method was that chemicals and catalysts were not involved when hydroxyl radical was generated from water and oxygen. A proportional efficiency of phenol removal was observed with the hydroxyl radical increasing. The removal efficiency was higher in a basic condition than in an acidic condition, which was enhanced with the pH value of the solution increasing from 3.6 to 11.2. It was rational to adjust the pH value between 9.0 and 10.0. The removal efficiency of phenol was reduced when the conductivity of the solution increased from 0 to 200 micros x cm(-1); the highest was found in the solution without Na2CO3. The UV spectral absorption in the process indicated that few organic compounds with a conjugated structure were included in the treated wastewater. PMID:19445335

  15. Fast Initiation and Mode Transition of Radio Frequency Induction Plasmas at Atmospheric Pressure Using Tungsten Pin Electrodes Array

    NASA Astrophysics Data System (ADS)

    Razzak, M. Abdur; Takamura, Shuichi; Ohno, Noriyasu

    The effects of using an array of tungsten pin electrodes on the ignition dynamics of radio frequency (rf) discharges generated by inductively coupled plasma (ICP) technique at atmospheric pressure are investigated experimentally. The experimental observations reveal that the array of tungsten pin electrodes successfully enhance the initial discharges maintained by the strong electrostatic field with stable and fast ignition, which enables us to sustain efficient rf induction plasmas at atmospheric pressure range.

  16. Surface plasma preionization produced on a specially patterned PCB and its application in a pulsed CO2 laser

    NASA Astrophysics Data System (ADS)

    Ghorbanzadeh, Atamalek; Pakmanesh, Nahid; Rastegari, Ali; Abdolghader, Pedram; Feizollah, Peyman; Siadati, Neda

    2016-04-01

    The performance of an atmospheric pressure pulsed carbon dioxide laser employing surface plasma preionization, produced on a specially patterned printed circuit board (PCB), is reported. The surface plasma is formed due to many tiny plasma channels produced in millimeter sized open circular gaps, made by lithography on one side of PCB. The preionizing plasma is mostly consisted of corona or glow stage and transition to spark one hardly occurs. This type of preionization allows a maximum of 220 J/l energy deposition into the main plasma, while up scaling is yet possible by more optimization of PCB and the pattern. The laser output energy of 1.2 J per pulse with overall efficiency of 7% has been obtained with gas mixture of He:CO2:N2=3:1:1. This type of surface plasma preionization is specifically appropriate for very large volumes and high pressures, where the conventional UV emitting preionizations like spark arrays or corona are not effective.

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

    ExperimentsfootnotetextJ. Oh, et al, GO5.4, APS DPP (2010).^,footnotetextJ. L. Weaver, et al, GO5.3, APS DPP (2010). using Nike KrF laser observed LPI signatures from CH plasmas at the laser intensities above 1x10^15 W/cm^2. Knowing spatial profiles of temperature (Te) and density (ne) in the underdense coronal region (0 < n < nc/4) of the plasma is essential to understanding the LPI observation. However, numerical simulation was the only way to access the profiles for the previous experiments. In the current Nike LPI experiment, a side-on grid imaging refractometer (GIR)footnotetextR. S. Craxton, et al, Phys. Fluids B 5, 4419 (1993). is being deployed for measuring the underdense plasma profiles. The GIR will resolve Te and ne in space taking a 2D snapshot of probe laser (?= 263 nm, ?t = 10 psec) beamlets (50?m spacing) refracted by the plasma at a selected time during the laser illumination. Time-resolved spectrometers with an absolute-intensity-calibrated photodiode array and a streak camera will simultaneously monitor light emission from the plasma in spectral ranges relevant to Raman (SRS) and two plasmon decay (TDP) instabilities. The experimental study of effects of the plasma profiles on the LPI initiation will be presented.

  18. Experimental study of the behavior of two laser produced plasmas in air

    NASA Astrophysics Data System (ADS)

    Yang, Zefeng; Wei, Wenfu; Han, Jiaxun; Wu, Jian; Li, Xingwen; Jia, Shenli

    2015-07-01

    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 1018 cm-3 and 2.4 1020 cm-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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  20. Pump-probe imaging of nanosecond laser-induced bubbles in distilled water solutions: Observations of laser-produced-plasma

    SciTech Connect

    Evans, R.; Camacho-Lopez, S.

    2010-11-15

    This article presents the analysis of the laser-produced-plasma (LPP) formed by the focusing of a 9 ns laser pulse, {lambda}=532 nm, with a NA=0.6 aspherical lens using energies between 100-1500 {mu}J, into distilled water with varying solutions of table salt. Observations of the filamentation plasma were made, which are explained by self-focusing of the laser pulse by the LPP through ponderomotive cavitation of the electron plasma in the center of the beam. The filamentation of the beam through a low density plasma wave guide explains why the transmission of the pump laser through the interaction region was notably higher on previous experiments that we performed [R. Evans et al., Opt. Express 16, 7481 (2008)], than a very similar set of experiments performed by Noack and Vogel [IEEE J. Quantum Electron. 35, 1156 (1999)].

  1. Nonthermal Biological Treatments Using Discharge Plasma Produced by Pulsed Power 4. Cleaning of Lakes and Marshes by Pulsed Power Produced Streamer Discharges in Water

    NASA Astrophysics Data System (ADS)

    Akiyama, Hidenori; Katsuki, Sunao; Namihira, Takao; Ishibashi, Kazuo; Kiyosaki, Noriaki

    Pulsed power has been used to produce non-thermal plasmas in atmospheric pressure gases that generate a high electric field at the tips of streamer discharges, where high energy electrons, free radicals, ultraviolet rays, and ozone are produced. These manifestations of streamer discharges have been used in the treatment of exhaust gases, removal of volatile and toxic compounds such as dioxin, and the sterilization of microorganisms. Here, large volume streamer discharges in water are described. These streamer discharges in liquids are able to produce a high electric field, high energy electrons, ozone, chemically active species, ultraviolet rays, and shock waves, which readily sterilize microorganisms and decompose molecules and materials. An application of this phenomenon to the cleaning of lakes and marshes is also described.

  2. Investigation of microwave plasmas produced in a mirror machine using ordinary-mode polarization

    NASA Astrophysics Data System (ADS)

    Ganguli, A.; Akhtar, M. K.; Tarey, R. D.

    1999-11-01

    This paper presents results of plasma production in a mirror machine with the microwaves being coupled from a side port, in the ordinary-mode polarization. In this method of coupling, contamination due to the launching antenna is avoided; also, there is very little window degradation since plasma bombardment on the side port is negligible. The coupling of the microwaves to the plasma in this method relies on the existence of certain surface waves that exist at low values of the magnetic field (below that for electron cyclotron resonance) and have a dominant Ez component. The existence of such surface waves is predicted by a recent theory (Ganguli A et al 1998 Phys. Plasmas 5 1178). The plasma characterization at microwave power levels of about 200 W, indicates moderately overdense plasmas (density icons/Journals/Common/approx" ALT="approx" ALIGN="TOP"/>1011 cm-3), with fairly uniform radial and axial profiles. From the data, the mechanism of plasma production and confinement in the mirror has been analysed. To gain insight into the nature of the waves in the plasma-loaded waveguide, the wavelengths of the waves within the plasma and the radial profiles of the wave electric field were measured. The results are compared with the theory of Ganguli et al for wave identification.

  3. High-order harmonic generation in a plasma plume of in situ laser-produced silver nanoparticles

    SciTech Connect

    Singhal, H.; Naik, P. A.; Chakera, J. A.; Chakravarty, U.; Vora, H. S.; Srivastava, A. K.; Mukherjee, C.; Navathe, C. P.; Deb, S. K.; Gupta, P. D.; Ganeev, R. A.

    2010-10-15

    The results of the experimental study of high-order harmonic generation (HHG) from the interaction of 45-fs Ti:sapphire laser pulses with plasma plumes of Ag nanoparticles produced in situ are presented in this article. The nanoparticles were generated by the interaction of 300-ps, 20-mJ laser pulses with bulk silver targets at an intensity of {approx}1x10{sup 13} W/cm{sup 2}. The spectral characteristics of the HHG from nanoparticles produced in situ are compared with the HHG from monoparticle plasma plumes and with the HHG from preformed nanoparticle-containing plasma plumes. The cutoff harmonic order generated using the in situ silver nanoparticles is at the 21st harmonic order.

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

    PubMed

    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. PMID:20580155

  5. A prospective study of endothelial activation biomarkers, including plasma angiopoietin-1 and angiopoietin-2, in Kenyan women initiating antiretroviral therapy

    PubMed Central

    2013-01-01

    Background HIV-1-related inflammation is associated with increased levels of biomarkers of vascular adhesion and endothelial activation, and may increase production of the inflammatory protein angiopoietin-2 (ANG-2), an adverse prognostic biomarker in severe systemic infection. We hypothesized that antiretroviral therapy (ART) initiation would decrease endothelial activation, reducing plasma levels of ANG-2. Methods Antiretroviral-nave Kenyan women with advanced HIV infection were followed prospectively. Endothelial activation biomarkers including soluble intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), and E-selectin, and plasma ANG-2 and angiopoietin-1 (ANG-1) were tested in stored plasma samples from 0, 6, and 12months after ART initiation. We used Wilcoxon matched-pairs signed rank tests to compare endothelial activation biomarkers across time-points, generalized estimating equations to analyze associations with change in log10-transformed biomarkers after ART initiation, and Cox proportional-hazards regression to analyze associations with mortality. Results The 102 HIV-1-seropositive women studied had advanced infection (median CD4 count, 124 cells/?L). Soluble ICAM-1 and plasma ANG-2 levels decreased at both time-points after ART initiation, with concomitant increases in the beneficial protein ANG-1. Higher ANG-2 levels after ART initiation were associated with higher plasma HIV-1 RNA, oral contraceptive pill use, pregnancy, severe malnutrition, and tuberculosis. Baseline ANG-2 levels were higher among five women who died after ART initiation than among women who did not (median 2.85ng/mL [inter-quartile range (IQR) 2.475.74ng/mL] versus median 1.32ng/mL [IQR 0.352.18ng/mL], p?=?0.01). Both soluble ICAM-1 and plasma ANG-2 levels predicted mortality after ART initiation. Conclusions Biomarkers of endothelial activation decreased after ART initiation in women with advanced HIV-1 infection. Changes in plasma ANG-2 were associated with HIV-1 RNA levels over 12months of follow-up. Soluble ICAM-1 and plasma ANG-2 levels represent potential biomarkers for adverse outcomes in advanced HIV-1 infection. PMID:23734875

  6. Demonstration of resistive inhibition of fast electrons from laser-produced plasmas in low-density gold targets

    SciTech Connect

    Bond, D.J.; Hares, J.D.; Kilkenny, J.D.

    1980-07-28

    A numerical model is used to show that the range of suprathermal electrons from laser produced plasmas can be significantly reduced by the electric field needed to drive a return current of cold electrons. Direct experimental evidence of a reduction of preheat by at least a factor of 3 is presented for targets containing a low-density gold layer.

  7. Study of DC discharge plasma polymerization kinetics, film properties and applications and initial study of silica powder surface modification by RF plasma polymerization

    NASA Astrophysics Data System (ADS)

    Guo, Sheyu

    1998-09-01

    In this work, two kinds of plasma polymerization for surface modification are discussed. In part-I, DC plasma polymerization is investigated for film properties, film growth mechanism and film application. The monomers heaxamethyldisiloxane (HMDSO) and pyrrole were selected to study the deposition rates change with discharge parameters such as pressure, flow rate, power, discharge current density. Structures and properties of film deposited at extreme conditions (high power/low pressure or low power/high pressure) were studied with FT-IR, SEM, TOF-SIMS, AIM, surface energy measurement and tribology test. This work also investigated DC plasma polymerization kinetics by combining plasma parameters with film deposited rate at different conditions. Both single and double Langmuir probes were used to measure the plasma parameters in pulsed power and continuous discharges. Plasma density and electron temperature are reported. A DC plasma polymerization kinetic model is Proposed based on the experimental data and a best-fit mathematical method. DC plasma polymerization application was the other object of this study. Cold-rolled steel and copper were coated with pyrrole and HMDSO, respectively. Corrosion rate were obtained from electrochemical polarization methods, and tests in humidity chamber directly. Various monomers were used to change the substrate surface energy. Hydrophilic and hydrophobic surface were achieved respectively by different monomers. A water-soluble film was obtained with acrylic acid in mild plasma conditions. In part-II, a initial study of powder surface modification has been done. The aim of this work was to investigate the possibility of changing powder surface properties with plasma-polymerized coatings. RF inductive plasma was used as a source to excite plasma polymerization for powder treatment. Plasma-polymerized pyrrole films were deposited on silica surface. Several techniques such as SEM, EDX, TOF-SIMS, FT-IF, DSC&TGA, and surface energy measurement were used for treated powder characterization. It was found that the film with several hundred angstrom thickness was deposited on silica surface. The silica became very hydrophobic. The performance test also showed that the rubber property was changed with pyrrole plasma treated silica.

  8. Cold plasma technologies for the inactivation of human pathogens on fresh and fresh-cut produce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research in cold plasma processing at the USDA’s Eastern Regional Research Center is focused on developing this technology into an effective tool to improve the safety of a variety of foods. Cold plasma applied to outbreak strains of Escherichia coli O157:H7 and Salmonella Stanley inoculated on the ...

  9. Investigation of a laser-produced bismuth plasma soft X-ray source

    NASA Astrophysics Data System (ADS)

    Otsuka, Takamitsu; Hayden, Paddy; O'Reilly, Fergal; Sokell, Emma; Dunne, Padraig; O'Sullivan, Gerry; Yugami, Noboru

    2013-10-01

    The emission spectra of many high- Z plasmas, with Z close to or greater than 50, are dominated in the soft X-ray region by a bright spectral feature known as an Unresolved Transition Array (UTA). This feature is attributed to hundreds of thousands of near-degenerate resonance lines from 4 d - 4 f and 4 p - 4 d type transitions. According to previous work, it was shown that the UTA peak wavelength depends on atomic number and will therefore extend down towards the water window region for high atomic numbers. In our previous paper, emission spectra from Bi plasma were observed to have a UTA peak around 4 nm. Calculated results also showed that there is strong UTA emission at 3.3 nm for plasma temperatures higher than 900 eV. However, this UTA emission has yet to be observed. Possible reasons for not observing this feature are the optical thickness of the Bi plasma itself and an inability to reach a sufficiently high plasma temperature. In order to obtain information on the optical thickness, absorption spectroscopy was carried out by way of the dual laser plasma photoabsorption technique. Two Nd:YAG lasers were focused on planar W and Bi targets. Emission from the W plasma was used to backlight Bi plasmas. Both emission and absorption spectra will be shown in the presentation. This work was supported by JSPS KAKENHI Grant Number 24?10265 and SFI Grant No. 07/ IN.1/1771.

  10. Cold Plasma Inactivates Salmonella and Escherichia coli O157:H7 on Fresh Produce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This presentation will summarize recent advances in cold plasma technology at the USDA’s Eastern Regional Research Center. Cold plasma generated in a gliding arc was applied to outbreak strains of Escherichia coli O157:H7 and Salmonella Stanley inoculated on the surfaces of golden delicious apples. ...

  11. Temperature measurements in plasmas produced by high-power lasers interacting with solid targets

    SciTech Connect

    Torrisi, L.; Gammino, S.; Picciotto, A.; Margarone, D.; Laska, L.; Krasa, J.; Rohlena, K.; Wolowski, J.

    2006-03-15

    One of the main goals of the study of plasmas generated by short or ultrashort laser pulses is the estimation of a complex parameter as the evaluation of the plasma temperature. Considering the laser-target and laser-plasma interactions as nonequilibrium processes, it is not possible to define a unique plasma temperature because the behavior of the different subsystems such as ions, electrons, neutral particles, and photons is not uniformly correlated, and the physical parameters can be different in different values of the plasma plume. In this work different experimental setups and techniques and different empirical and theoretical approaches are compared by using a Nd:YAG laser with an intensity of 10{sup 10} W/cm{sup 2} and an iodine laser with an intensity of 10{sup 15}-10{sup 16} W/cm{sup 2}. Time-of-flight measurements have been performed with an ion-energy analyzer and by using a number of Faraday cups in order to measure the velocity and the kinetic energy of ions and electrons emitted by the plasma. The obtained results have been relevant to confirm that by using a Nd:YAG laser the plasma ion temperature in the plasma core is about 400 eV. The electron emission indicates the presence of hot electrons with an energy of about 1 keV. These results will be compared with the ones obtained with the powerful iodine laser at Prague Asterix Laser System.

  12. Real-time measurement of materials properties at high temperatures by laser produced plasmas

    NASA Technical Reports Server (NTRS)

    Kim, Yong W.

    1990-01-01

    Determination of elemental composition and thermophysical properties of materials at high temperatures, as visualized in the context of containerless materials processing in a microgravity environment, presents a variety of unusual requirements owing to the thermal hazards and interferences from electromagnetic control fields. In addition, such information is intended for process control applications and thus the measurements must be real time in nature. A new technique is described which was developed for real time, in-situ determination of the elemental composition of molten metallic alloys such as specialty steel. The technique is based on time-resolved spectroscopy of a laser produced plasma (LPP) plume resulting from the interaction of a giant laser pulse with a material target. The sensitivity and precision were demonstrated to be comparable to, or better than, the conventional methods of analysis which are applicable only to post-mortem specimens sampled from a molten metal pool. The LPP technique can be applied widely to other materials composition analysis applications. The LPP technique is extremely information rich and therefore provides opportunities for extracting other physical properties in addition to the materials composition. The case in point is that it is possible to determine thermophysical properties of the target materials at high temperatures by monitoring generation and transport of acoustic pulses as well as a number of other fluid-dynamic processes triggered by the LPP event. By manipulation of the scaling properties of the laser-matter interaction, many different kinds of flow events, ranging from shock waves to surface waves to flow induced instabilities, can be generated in a controllable manner. Time-resolved detection of these events can lead to such thermophysical quantities as volume and shear viscosities, thermal conductivity, specific heat, mass density, and others.

  13. Solution of the explosive percolation quest. II. Infinite-order transition produced by the initial distributions of clusters

    NASA Astrophysics Data System (ADS)

    da Costa, R. A.; Dorogovtsev, S. N.; Goltsev, A. V.; Mendes, J. F. F.

    2015-03-01

    We describe the effect of power-law initial distributions of clusters on ordinary percolation and its generalizations, specifically, models of explosive percolation processes based on local optimization. These aggregation processes were shown to exhibit continuous phase transitions if the evolution starts from a set of disconnected nodes. Since the critical exponents of the order parameter in explosive percolation transitions turned out to be very small, these transitions were first believed to be discontinuous. In this article we analyze the evolution starting from clusters of nodes whose sizes are distributed according to a power law. We show that these initial distributions change dramatically the position and order of the phase transitions in these problems. We find a particular initial power-law distribution producing a peculiar effect on explosive percolation, namely, before the emergence of the percolation cluster, the system is in a "critical phase" with an infinite generalized susceptibility. This critical phase is absent in ordinary percolation models with any power-law initial conditions. The transition from the critical phase is an infinite-order phase transition, which resembles the scenario of the Berezinskii-Kosterlitz-Thouless phase transition. We obtain the critical singularity of susceptibility at this peculiar infinite-order transition in explosive percolation. It turns out that susceptibility in this situation does not obey the Curie-Weiss law.

  14. Self-initiating volume discharge in iodides used for producing atomic iodine in pulsed chemical oxygen - iodine lasers

    SciTech Connect

    Belevtsev, A A; Kazantsev, S Yu; Saifulin, A V; Firsov, K N

    2003-06-30

    A volume self-sustained discharge (VSD) in iodides (C{sub 3}H{sub 7}I, C{sub 4}H{sub 9}I) and in their mixtures with SF{sub 6}, N{sub 2}, and O{sub 2} in the presence of small-scale inhomogeneities on the cathode surface is shown to develop in the form of a self-initiating volume discharge (SIVD), i.e., a volume discharge without any preionisation including discharge gaps with a strong edge enhancement of the electric field. Additions of SF{sub 6} or N{sub 2} to the iodides improves the stability and homogeneity of the SIVD, while adding up to 300 % (relative to the partial iodide pressure) of O{sub 2} to these mixtures has only an insignificant effect on the discharge stability. The possibility of SIVD initiation was modelled experimentally in a 1.5-L discharge volume. For the C{sub 4}H{sub 9}I:O{sub 2}:SF{sub 6}=0.083:0.25:0.67 mixture at a pressure of 72 Torr, the specific energy input into the discharge plasma ranged up to 130 J L{sup -1} in this geometry. A conclusion was drawn that the SIVD is promising for the production of atomic iodine in the pulsed and repetitively pulsed operating regimes of a chemical oxygen - iodine laser. (lasers)

  15. Risk factors for initial respiratory disease in United States' feedlots based on producer-collected daily morbidity counts.

    PubMed

    Sanderson, Michael W; Dargatz, David A; Wagner, Bruce A

    2008-04-01

    The incidence of initial respiratory disease was followed for 12 weeks in 122 pens of feedlot cattle, based on producer-collected daily morbidity counts. Weekly incidence density was calculated based on the number of new cases and the population at risk. Incidence density was greatest in the 1st week after arrival and decreased in following weeks. Weekly incidence rate varied between pens and over time from 0 to 27.7 cases per 100 animal weeks at risk. A negative binomial model controlling for multiple events within pens and over time was used to model effects on the number of new cases. Mixed gender groups, cattle from multiple sources and increasing distance shipped were associated with increased risk for initial respiratory morbidity. Heavier entry weight was associated with decreased morbidity risk. These factors may be useful in categorizing groups of calves into risk groups for targeted purchase and management decision making. PMID:18481546

  16. Investigation of plasmas produced by laser ablation using single and double pulses for food analysis demonstrated by probing potato skins.

    PubMed

    Beldjilali, S; Yip, W L; Hermann, J; Baba-Hamed, T; Belasri, A

    2011-06-01

    We report on investigations of plasmas produced by laser ablation of fresh potatoes using infrared nanosecond laser radiation. A twin laser system consisting of two Nd:YAG oscillators was used to generate single or double pulses of adjustable interpulse delay. The potatoes were irradiated under ambient air with moderate pulse energies of about 10 mJ. The expansion dynamics of the ablation plume was characterized using fast imaging with a gated camera. In addition, time-resolved optical emission spectroscopy was applied to study the spectral line emission of the various plasma species. The electron density was deduced from Stark broadening, and the plasma temperature was inferred from the relative emission intensities of spectral lines. The relative concentrations of metals were estimated from the comparison of the measured emission spectra to the spectral radiance computed for a plasma in local thermal equilibrium. It is shown that the plasma produced by double pulses has a larger volume and a lower density. These properties lead to an increase of the signal-to-noise ratio by a factor of 2 and thus to an improved measurement sensitivity. PMID:21461618

  17. Recent progress in space- and time-resolved x-ray spectroscopy of laser-produced plasmas (abstract)

    NASA Astrophysics Data System (ADS)

    Young, B. K. F.

    1990-10-01

    New diagnostic techniques have provided measurement of relatively gradient-free x-ray spectra from high-powered laser-produced plasmas. Simultaneously space- and time-resolved x-ray spectra were measured from a variety of microdot plasmas using an array of multiframe, imaging, electronically gated x-ray crystal spectrometers with 100 ps time resolution. A multiframed, multicolored gated x-ray pinhole camera provided measurement of the plasma uniformity. A four-frame holographic interferometer was used to measure the electron density profile. Conventional x-ray streaked crystal spectrographs, spatially resolved x-ray (film) spectrometer, and pinhole cameras supplemented these new diagnostics. The instruments allow detailed studies of both the population kinetics of highly charged ions in dense plasmas and the hydrodynamics of laser-produced plasmas for the first time. The new diagnostics are described including data from ongoing experiments. Work was performed in part under the auspices of the U.S. Dept. of Energy by LLNL under Contract No. W-7405-Eng-48.

  18. Experiments on a laser-produced plasma cross-field motion for simulation of interaction between CRRES releases and geoplasma

    SciTech Connect

    Zakharov, Yu.P.; Wolowski, J.

    1995-12-31

    A new class of simulation experiments with laser-produced plasmas is discussed with reference to recent results of CRRES-mission investigations. For better understanding of a low-Ma interaction processes of ionospheric and magnetospheric Barium releases with a surrounding magnetized geoplasma, simulation experiments are proposed at high-intensity magnetic fields and with the presence of a low-density partially ionized background. Such experiments have become possible owing to successful simulations of the AMPTE-release and preliminary studies of cross-field plasma motion performed at the KI-1 facility in Novosibirsk, as well as due to extension of the possibilities of high-intensity magnetic field--laser-produced plasma interaction experiments in Warsaw. In particular, the authors hope to achieve the value of the main similarity criterion of the problem of the ion magnetization parameter, in common simulation experiments. In such conditions, it is very interesting to simulate the development of high-mode ({ge} 50) flute instabilities as well as propagation of plasma blobs across the field at the distance > Rh. In simulation of an ionospheric release, the main goal is to study the background plasma influence on such propagation, its acceleration by Ba cloud, and finally, recently revealed development of Langmuir and ion-cyclotron wave activities in the last processes. The authors present some discussion on the physics of the above mentioned interaction processes (for performing simulation experiments with adequate similarity criteria) as well as the parameters of such experiments and methods for their accomplishment.

  19. Development of a Laser-Produced Plasma X-ray source for Phase-Contrast Radiography of DT Ice layers

    SciTech Connect

    Izumi, N; Dewald, E; Kozioziemski, B; Landen, O L; Koch, J A

    2008-07-21

    Refraction enhanced x-ray phase contrast imaging is crucial for characterization of deuterium-tritium (DT) ice layer roughness in optically opaque inertial confinement fusion capsules. To observe the time development of DT ice roughness over {approx} second timescales, we need a bright x-ray source that can produce an image faster than the evolution of the ice surface roughness. A laser produced plasma x-ray source is one of the candidates that can meet this requirement. We performed experiments at the Janus laser facility at Lawrence Livermore National Laboratory and assessed the characteristics of the laser produced plasma x-ray source as a potential backlight for in situ target characterization.

  20. The Influence of spot size on the expansion dynamics of nanosecond-laser-produced copper plasmas in atmosphere

    SciTech Connect

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

    2013-06-28

    Laser produced copper plasmas of different spot sizes in air were investigated using fast photography and optical emission spectroscopy (OES). The laser energy was 33 mJ. There were dramatic changes in the plasma plume expansion into the ambient air when spot sizes changed from {approx}0.1 mm to {approx}0.6 mm. A stream-like structure and a hemispherical structure were, respectively, observed. It appeared that the same spot size resulted in similar expansion dynamics no matter whether the target was located in the front of or behind the focal point, although laser-induced air breakdown sometimes occurred in the latter case. Plasma plume front positions agree well with the classic blast wave model for the large spot-size cases, while an unexpected stagnation of {approx}80 ns occurred after the laser pulse ends for the small spot size cases. This stagnation can be understood in terms of the evolution of enhanced plasma shielding effects near the plasma front. Axial distributions of plasma components by OES revealed a good confinement effect. Electron number densities were estimated and interpreted using the recorded Intensified Charge Coupled Device (ICCD) images.

  1. Visualizing electromagnetic fields in laser-produced counter-streaming plasma experiments for collisionless shock laboratory astrophysics

    SciTech Connect

    Kugland, N. L.; Ross, J. S.; Glenzer, S. H.; Huntington, C.; Martinez, D.; Plechaty, C.; Remington, B. A.; Ryutov, D. D.; Park, H.-S.; Chang, P.-Y.; Fiksel, G.; Froula, D. H.; Drake, R. P.; Grosskopf, M.; Kuranz, C.; Gregori, G.; Meinecke, J.; Reville, B.; Koenig, M.; Pelka, A.; and others

    2013-05-15

    Collisionless shocks are often observed in fast-moving astrophysical plasmas, formed by non-classical viscosity that is believed to originate from collective electromagnetic fields driven by kinetic plasma instabilities. However, the development of small-scale plasma processes into large-scale structures, such as a collisionless shock, is not well understood. It is also unknown to what extent collisionless shocks contain macroscopic fields with a long coherence length. For these reasons, it is valuable to explore collisionless shock formation, including the growth and self-organization of fields, in laboratory plasmas. The experimental results presented here show at a glance with proton imaging how macroscopic fields can emerge from a system of supersonic counter-streaming plasmas produced at the OMEGA EP laser. Interpretation of these results, plans for additional measurements, and the difficulty of achieving truly collisionless conditions are discussed. Future experiments at the National Ignition Facility are expected to create fully formed collisionless shocks in plasmas with no pre-imposed magnetic field.

  2. Soft-x-ray spectroscopy of subpicosecond laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Krushelnick, K. M.; Tighe, W.; Suckewer, S.

    1996-02-01

    Experiments that examine the interaction of high-intensity subpicosecond laser radiation ( \\similar 1018 W / cm2) with solid targets are performed. Soft-x-ray spectra from interactions with Teflon and aluminum targets that imply the creation of high-temperature ( > 200 eV) high-density ( > 10 23 cm -3 ) plasmas are obtained. Effects of a prepulse on the plasma characteristics are examined. The applicability of short, intense laser pulses for the formation of population inversions on x-ray transitions during recombination of high-density plasmas is discussed. 42.55.Vc.

  3. Plasma channel produced by femtosecond laser pulses as a medium for amplifying electromagnetic radiation of the subterahertz frequency range

    SciTech Connect

    Bogatskaya, A V; Volkova, E A; Popov, A M

    2013-12-31

    The electron energy distribution function in the plasma channel produced by a femtosecond laser pulse with a wavelength of 248 nm in atmospheric-pressure gases was considered. Conditions were determined whereby this channel may be employed for amplifying electromagnetic waves up to the terahertz frequency range over the energy spectrum relaxation time ?10{sup -7} s. Gains were calculated as functions of time and radiation frequency. The effect of electron electron collisions on the rate of relaxation processes in the plasma and on its ability to amplify the electromagnetic radiation was investigated. (interaction of laser radiation with matter)

  4. X-ray spectrum in the range (6-12) A emitted by laser-produced plasma of samarium

    SciTech Connect

    Louzon, Einat; Henis, Zohar; Levi, Izhak; Hurvitz, Gilad; Ehrlich, Yosi; Fraenkel, Moshe; Maman, Shlomo; Mandelbaum, Pinchas

    2009-05-15

    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.

  5. Mass spectrometric study of discharges produced by a large-area dual-frequency-dual-antenna inductively coupled plasma source

    NASA Astrophysics Data System (ADS)

    Mishra, Anurag; Kim, Tae Hyung; Kim, Kyong Nam; Yeom, Geun Young

    2012-11-01

    An energy-resolved quadrupole mass spectrometer is used to investigate the time-averaged ion energy distribution (IED) of positive ionic species in an Ar/CF4 (90%/10%) discharge produced by dual-frequency-dual-antenna, next-generation large-area inductively coupled plasma source. The operating pressure is 10 mTorr. Two radio frequencies of 2 MHz (low frequency) and 13.56 MHz (high frequency) are used to initiate and sustain the discharge. The orifice of the mass spectrometer was 100 m in diameter and placed at 30 mm below the ICP source and 20 mm outside the discharge volume. It is observed that both of the frequencies have significant effect on IEDs of all prominent discharge species. The evolution of IEDs with power shows that the discharge undergoes a mode transition (E to H) as the applied power is increased. At a fixed value of P13.56 MHz (250 and 500 W), the energy spread and the energy separation between two peaks of IEDs increase illustrating enhanced E-mode. Above P13.56 MHz = 500 W, the IEDs show opposite trends, i.e. decreasing energy spread and energy separation between two peaks, showing the strengthening of H-mode. Increasing P13.56 MHz at a fixed value of P2 MHz has similar effects. A comparison of IEDs sampled at a fixed total power (P13.56 MHz + P2 MHz) demonstrates that an IED can be tailored by changing the power ratio (P13.56 MHz/P2 MHz).

  6. Thermal inequilibrium of atmospheric helium microwave plasma produced by an axial injection torch

    SciTech Connect

    Alvarez, R.; Rodero, A.; Quintero, M.C.; Sola, A.; Gamero, A.; Ortega, D.

    2005-11-01

    The population density of several excited states has been obtained spectroscopically in a helium plasma sustained by a torch device at atmospheric pressure as a function of the radius in the plasma for different conditions of microwave power and plasma gas flow. The ground-state atom density is determined from the gas temperature, which is deduced from the rotational temperature of the molecular nitrogen ions. The population distribution is fitted to the theoretical results of a collisional-radiative model that includes particle transport. A large deviation of the measured populations is found from the theoretical populations for local thermodynamic equilibrium. The plasma at any radial position is far from local thermodynamic equilibrium; the equilibrium deviation parameter of the ground state is larger than 10 000. The equilibrium deviation parameters of the measured excited-state populations obey the theoretical p{sub k}{sup -6} exponential law.

  7. Spectral analysis of the acoustic emission of laser-produced plasmas.

    PubMed

    Palanco, Santiago; Laserna, Javier

    2003-10-20

    A Q-switched frequency Nd:YAG laser was focused on copper, aluminum, and lead targets. The acoustic emission accompanying plasma formation was acquired and analyzed in both the time and the frequency domains. Spectral analysis of the shock wave has proved to be a simple and low-cost diagnostic of plasma phenomena. In the time domain, several propagation mechanisms of the shock wave were observed and the velocity profile of the shock wave estimated. Spectral measurements were performed in the acoustic propagation regime of the shock waves. Spectral features related to the plasma formation mechanism were identified and discussed for copper, aluminum, and lead on the basis of the physical properties of these elements, the expansion mechanisms of the plasma, and an empirical parameter representative of the transported energy. PMID:14594069

  8. Propagation velocities of laser-produced plasmas from copper wire targets and water droplets

    NASA Technical Reports Server (NTRS)

    Song, Kyo-Dong; Alexander, Dennis R.

    1994-01-01

    Experiments were performed to determine the plasma propagation velocities resulting from KrF laser irradiation of copper wire target (75 microns diameter) and water droplets (75 microns diameter) at irradiance levels ranging from 25 to 150 GW/sq cm. Plasma propagation velocities were measured using a streak camera system oriented orthogonally to the high-energy laser propagation axis. Plasma velocities were studied as a function of position in the focused beam. Results show that both the shape of the plasma formation and material removal from the copper wire are different and depend on whether the targets are focused or slightly defocused (approximately = 0.5 mm movement in the beam axis). Plasma formation and its position relative to the target is an important factor in determining the practical focal point during high-energy laser interaction with materials. At irradiance of 100 GW/sq cm, the air plasma has two weak-velocity components which propagate toward and away from the incident laser while a strong-velocity component propagates away from the laser beam as a detonation wave. Comparison of the measured breakdown velocities (in the range of 2.22-2.27 x 10(exp 5) m/s) for air and the value calculated by the nonlinear breakdown wave theory at irradiance of 100 GW/sq cm showed a quantitative agreement within approximately 50% while the linear theory and Gaussian pulse theory failed. The detonation wave velocities of plasma generated from water droplets and copper wire targets for different focused cases were measured and analyzed theoretically. The propagation velocities of laser-induced plasma liquid droplets obtained by previous research are compared with current work.

  9. X-ray characterization of high energy density plasmas produced in mega-joule laser experiments on the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Glenzer, Siegfried

    2010-03-01

    With completion of the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory the quest for producing a burning fusion plasma has begun. The goal of these experiments is to compress matter to densities and temperatures higher than the interior of the sun to initiate nuclear fusion and burn of hydrogen isotopes. In the first indirect-drive hohlraum experiments on NIF, we have demonstrated symmetric capsule implosions at unprecedented conditions of mega-joule laser energies. 192 simultaneously fired laser beams heat ignition hohlraums to radiation temperatures of 3.3 million Kelvin compressing 2-millimeter capsules by the soft x rays produced inside the hohlraum. In these experiments, symmetry and velocity of the implosion are measured by imaging the 9 keV capsule x-ray emission on a temporally resolving 2-D detector. In addition, x-ray radiography and scattering techniques are being developed for measuring the density and temperature of the implosion. The experiments indicate conditions suitable for compressing deuterium-tritium filled capsules with the goal to produce burning fusion plasmas in the laboratory.

  10. Spectral and ion emission features of laser-produced Sn and SnO2 plasmas

    NASA Astrophysics Data System (ADS)

    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.

  11. Potential formation in a collisionless plasma produced in an open magnetic field in presence of volume negative ion source

    SciTech Connect

    Phukan, Ananya Goswami, K. S.; Bhuyan, P. J.

    2014-08-15

    The electric potential near a wall for a multi-species plasma with volume produced negative ions in presence of axially varying magnetic field is studied following an analytical-numerical approach. A constant negative ion source is assumed throughout the plasma volume, along with finite temperature positive ions and Boltzmann electrons. The particles are assumed to be guided by an open magnetic field that has its maximum at the centre, and field strength decreasing towards the walls. The one dimensional (1D) Poisson equation is derived using an analytical approach, and then solved numerically to study the potential profiles. Effect of (a) negative ion production rate, (b) magnetic field profile, and (c) negative ion temperature on the potential profile has been investigated. A potential peak appears near the wall when the negative ion temperature and density are sufficiently high. Also, the presence of negative ions further decreases the potential in the plasma region for a finite Debye Length (?{sub D})

  12. Spectra of multiply charged hollow ions in the plasma produced by a short-wavelength nanosecond laser

    SciTech Connect

    Abdallah, J; Skobelev, I Yu; Faenov, A Ya; Magunov, A I; Pikuz, T A; Flora, F; Bollanti, S; DiLazzaro, P; Letardi, T; Burattini, E; Grilli, A; Reale, A; Palladino, L; Tomassetti, G; Scafati, A; Reale, L

    2000-08-31

    Complex spectral structures located between the resonance lines of H- and He-like MgXII and MgXI ions were recorded in experiments on plasma heating by the radiation of a low-power short-wavelength excimer XeCl laser (12-ns pulses with an energy of 2 J). The above spectral structures were shown to arise from transitions in the so-called hollow multicharged ions, i.e., in ions with an empty 1s-shell, which were previously observed in laser produced plasmas only with ultrahigh-power femto- and picosecond laser facilities having extremely high-contrast laser pulses. (interaction of laser radiation with matter. laser plasma)

  13. Refraction-Enhanced X-ray Radiography for Inertial Confinement Fusion and Laser-Produced Plasma Applications

    SciTech Connect

    Koch, J A; Landen, O L; Kozioziemski, B J; Izumi, N; Dewald, E L; Salmonson, J D; Hammel, B A

    2008-08-26

    We explore various laser-produced plasma and inertial-confinement fusion (ICF) applications of phase-contrast x-ray radiography, and we show how the main features of these enhancements can be considered from a geometrical optics perspective as refraction enhancements. This perspective simplifies the analysis, and often permits simple analytical formulae to be derived that predict the enhancements. We explore a raytrace approach to various material interface applications, and we explore a more general example of refractive bending of x-rays by an implosion plasma. We find that refraction-enhanced x-ray radiography of implosions may provide a means to quantify density differences across shock fronts as well as density variations caused by local heating due to high-Z dopants. We also point out that refractive bending by implosions plasmas can blur fine radiograph features, and can also provide misleading contrast information in area-backlit pinhole imaging experiments unless its effects are taken into consideration.

  14. Measurement of Laser Plasma Instability (LPI) Driven Light Scattering from Plasmas Produced by Nike KrF Laser

    NASA Astrophysics Data System (ADS)

    Oh, Jaechul; Weaver, J. L.; Phillips, L.; Obenschain, S. P.; Schmitt, A. J.; Kehne, D. M.; Serlin, V.; Lehmberg, R. H.; McLean, E. A.; Manka, C. K.

    2010-11-01

    With short wavelength (248 nm), large bandwidth (13 THz), and ISI beam smoothing, Nike KrF laser provides unique research opportunities and potential for direct-drive inertial confinement fusion. Previous Nike experiments observed two plasmon decay (TPD) driven signals from CH plasmas at the laser intensities above 2x10^15 W/cm^2 with total laser energies up to 1 kJ of 350 ps FWHM pulses. We have performed a further experiment with longer laser pulses (0.54.0 ns FWHM) and will present combined results of the experiments focusing on light emission data in spectral ranges relevant to the Raman (SRS) and TPD instabilities. Time- or space-resolved spectral features of TPD were detected at different viewing angles and the absolute intensity calibrated spectra of thermal background were used to obtain blackbody temperatures in the plasma corona. The wave vector distribution in k-space of the participating TPD plasmons will be also discussed. These results show promise for the proposed direct-drive designs.

  15. Infrared nanosecond laser-metal ablation in atmosphere: Initial plasma during laser pulse and further expansion

    SciTech Connect

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

    2013-04-22

    We have investigated the dynamics of the nanosecond laser ablated plasma within and after the laser pulse irradiation using fast photography. A 1064 nm, 15 ns laser beam was focused onto a target made from various materials with an energy density in the order of J/mm{sup 2} in atmosphere. The plasma dynamics during the nanosecond laser pulse were observed, which could be divided into three stages: fast expansion, division into the primary plasma and the front plasma, and stagnation. After the laser terminated, a critical moment when the primary plasma expansion transited from the shock model to the drag model was resolved, and this phenomenon could be understood in terms of interactions between the primary and the front plasmas.

  16. Sweep Langmuir Probe and Triple Probe Diagnostics for Transient Plasma Produced by Hypervelocity Impact

    NASA Astrophysics Data System (ADS)

    Tang, Enling; Xiang, Shenghai; Yang, Minghai; Li, Lexin

    2012-08-01

    Two techniques are applied to diagnose characteristic parameters of plasma created by hypervelocity impact, such as electron temperature and electron density. The first technique is a sweep Langmuir probe (SLP), which is a new apparatus based on a dual channel circuit that can compensate for stray capacitance and obtain a good synchronicity, so that electrostatic turbulence with a good temporal resolution can be acquired. The second technique is a triple Langmuir probe (TLP), which is an electrostatic triple Langmuir probe diagnostic system, in which no voltage and frequency sweep is required. This technique allows to measure electron temperature, electron density as a function of time. Moreover, the triple Langmuir probe diagnostic system allows the direct display of electron temperature and semidirect display of electron density by an appropriate display system, the system permits us to eliminate almost all data processing procedures. SLP and TLP were applied to obtain fluctuations of the characteristic parameters of plasma generated by hypervelocity impact. As an example of their application to time-dependent plasma measurement, the electron temperature and electron density of plasmas were acquired in hypervelocity impact experiments. Characteristic parameters of plasma generated by hypervelocity impact were compared by the two kinds of diagnostic techniques mentioned above.

  17. Diagnostics of plasma produced by femtosecond laser pulse impact upon a target with an internal nanostructure

    NASA Astrophysics Data System (ADS)

    Skobelev, I. Yu.; Faenov, A. Ya.; Gasilov, S. V.; Pikuz, T. A.; Pikuz, S. A.; Magunov, A. I.; Boldarev, A. S.; Gasilov, V. A.

    2010-12-01

    X-ray diagnostics of the interaction of femtosecond laser pulses with intensities of 1016-1018 W/cm2 with CO2 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.

  18. A hemispherical Langmuir probe array detector for angular resolved measurements on droplet-based laser-produced plasmas

    SciTech Connect

    Gambino, Nadia Brandstätter, Markus; Rollinger, Bob; Abhari, Reza

    2014-09-15

    In this work, a new diagnostic tool for laser-produced plasmas (LPPs) is presented. The detector is based on a multiple array of six motorized Langmuir probes. It allows to measure the dynamics of a LPP in terms of charged particles detection with particular attention to droplet-based LPP sources for EUV lithography. The system design permits to temporally resolve the angular and radial plasma charge distribution and to obtain a hemispherical mapping of the ions and electrons around the droplet plasma. The understanding of these dynamics is fundamental to improve the debris mitigation techniques for droplet-based LPP sources. The device has been developed, built, and employed at the Laboratory for Energy Conversion, ETH Zürich. The experimental results have been obtained on the droplet-based LPP source ALPS II. For the first time, 2D mappings of the ion kinetic energy distribution around the droplet plasma have been obtained with an array of multiple Langmuir probes. These measurements show an anisotropic expansion of the ions in terms of kinetic energy and amount of ion charge around the droplet target. First estimations of the plasma density and electron temperature were also obtained from the analysis of the probe current signals.

  19. Advanced properties of extended laser-produced plasmas for efficient generation of the high-order harmonics of ultrashort laser pulses

    NASA Astrophysics Data System (ADS)

    Ganeev, R. A.

    2015-04-01

    The review of the studies showing the advanced properties of extended plasma plumes (5 mm) for efficient high-order harmonic generation of laser radiation compared with the short lengths of plasmas (~0.3-0.5 mm) used in previous studies is presented. The harmonic conversion efficiency quadratically increased with the growth of plasma length at the optimal conditions of plasma formation. The studies of this process using the long plasma jets produced on various metal surfaces, particularly including the resonance-enhanced harmonic generation, two-color pump, and extended nanoparticle plasma, are discussed.

  20. Optimization of the neutron yield in fusion plasmas produced by Coulomb explosions of deuterium clusters irradiated by a petawatt laser.

    PubMed

    Bang, W; Dyer, G; Quevedo, H J; Bernstein, A C; Gaul, E; Donovan, M; Ditmire, T

    2013-02-01

    The kinetic energy of hot (multi-keV) ions from the laser-driven Coulomb explosion of deuterium clusters and the resulting fusion yield in plasmas formed from these exploding clusters has been investigated under a variety of conditions using the Texas Petawatt laser. An optimum laser intensity was found for producing neutrons in these cluster fusion plasmas with corresponding average ion energies of 14 keV. The substantial volume (1-10 mm(3)) of the laser-cluster interaction produced by the petawatt peak power laser pulse led to a fusion yield of 1.610(7) neutrons in a single shot with a 120 J, 170 fs laser pulse. Possible effects of prepulses are discussed. PMID:23496630

  1. Optimization of the neutron yield in fusion plasmas produced by Coulomb explosions of deuterium clusters irradiated by a petawatt laser

    NASA Astrophysics Data System (ADS)

    Bang, W.; Dyer, G.; Quevedo, H. J.; Bernstein, A. C.; Gaul, E.; Donovan, M.; Ditmire, T.

    2013-02-01

    The kinetic energy of hot (multi-keV) ions from the laser-driven Coulomb explosion of deuterium clusters and the resulting fusion yield in plasmas formed from these exploding clusters has been investigated under a variety of conditions using the Texas Petawatt laser. An optimum laser intensity was found for producing neutrons in these cluster fusion plasmas with corresponding average ion energies of 14 keV. The substantial volume (1-10 mm3) of the laser-cluster interaction produced by the petawatt peak power laser pulse led to a fusion yield of 1.6107 neutrons in a single shot with a 120 J, 170 fs laser pulse. Possible effects of prepulses are discussed.

  2. Radiation environments produced by plasma Z-pinch stagnation on central targets

    SciTech Connect

    Brownell, J.H.; Bowners, R.L.; McLenithan, K.D.; Peterson, D.L.

    1997-11-01

    A goal of modern pulsed-power technology is the development of an intense, megajoule level source of soft x-rays for use in high-energy density physics experiments. Since 1980 experimental facilities, theoretical concepts, computational tools, and diagnostics have been developed that place pulsed-power at the threshold of performing experiments of great interest to the applied physics community. In this paper the ``Flying Radiation Case`` approach will be presented and its predicted performance on Sandia National Laboratory`s Z-Machine [M.K. Matzen, Phys. Plasmas 4, 1519 (1997)] is described. The effects of instability growth in the plasma during the implosion, its reassembly on a central cushion, and the plasma interactions with shaped electrodes are considered.

  3. [Radiation properties of plasma produced by ultraviolet laser ablation of metal Cu].

    PubMed

    Huang, Qing-Ju

    2008-02-01

    Time-resolved measurement of plasma plume emission spectra from XeCl excimer laser ablation of copper in nitrogen is reported. The experimental results indicate that the plasma emission spectra are mainly composed of atomic spectrum, univalent ion spectrum and continuous radiation, and these spectral lines have different number, intensity and duration. The main detailed mechanism of species excitation was discussed. The electrons obtain high-kinetic energy through reverse bremsstrahlung, the continuous radiation comes from the bremsstrahlung emission of energetic electrons ejected from the target, the excitation mechanism of atomic and univalent ion is inelastic collision between the elemental species and high kinetic-energy electron, and recombination of electron and ion in the plasma, and the model can be used to explain the experimental results qualitatively. PMID:18479003

  4. Injection and acceleration of electron bunch in a plasma wakefield produced by a chirped laser pulse

    SciTech Connect

    Afhami, Saeedeh; Eslami, Esmaeil

    2014-06-15

    An ultrashort laser pulse propagating in plasma can excite a nonlinear plasma wakefield which can trap and accelerate charged particles up to GeV. One-dimensional analysis of electron injection, trapping, and acceleration by different chirped pulses propagating in plasma is investigated numerically. In this paper, we inject electron bunches in front of the chirped pulses. It is indicated that periodical chirped laser pulse can trap electrons earlier than other pulses. It is shown that periodical chirped laser pulses lead to decrease the minimum momentum necessary to trap the electrons. This is due to the fact that periodical chirped laser pulses are globally much efficient than nonchirped pulses in the wakefield generation. It is found that chirped laser pulses could lead to much larger electron energy than that of nonchirped pulses. Relative energy spread has a lower value in the case of periodical chirped laser pulses.

  5. A Black-box Modelling Engine for Discharge Produced Plasma Radiation Sources

    NASA Astrophysics Data System (ADS)

    Zakharov, S. V.; Choi, P.; Krukovskiy, A. Y.; Novikov, V. G.; Zakharov, V. S.; Zhang, Q.

    2006-01-01

    A Blackbox Modelling Engine (BME), is an instrument based on the adaptation of the RMHD code Z*, integrated into a specific computation environment to provide a turn key simulation instrument and to enable routine plasma modelling without specialist knowledge in numerical computation. Two different operating modes are provided: Detailed Physics mode & Fast Numerics mode. In the Detailed Physics mode, non-stationary, non-equilibrium radiation physics have been introduced to allow the modelling of transient plasmas in experimental geometry. In the Fast Numerics mode, the system architecture and the radiation transport is simplified to significantly accelerate the computation rate. The Fast Numerics mode allows the BME to be used realistically in parametric scanning to explore complex physical set up, before using the Detailed Physics mode. As an example of the results from the BME modelling, the EUV source plasma dynamics in the pulsed capillary discharge are presented.

  6. Influence of atomic modeling on integrated simulations of laser-produced Au plasmas

    NASA Astrophysics Data System (ADS)

    Frank, Yechiel; Raicher, Erez; Ehrlich, Yosi; Hurvitz, Gilad; Shpilman, Zeev; Fraenkel, Moshe; Zigler, Arie; Henis, Zohar

    2015-11-01

    Time-integrated x-ray emission spectra of laser-irradiated Au disks were recorded using transmission grating spectrometry, at laser intensities of 1013 to 1014W/cm2 . Radiation-hydrodynamics and atomic physics calculations were used to simulate the emitted spectra. Three major plasma regions can be recognized: the heat wave, the corona, and an intermediate region connecting them. An analysis of the spectral contribution of these three plasma regions to the integrated recorded spectrum is presented. The importance of accurate atomic modeling of the intermediate plasma region, between the corona and the heat wave, is highlighted. The influence of several aspects of the atomic modeling is demonstrated, in particular multiply-excited atomic configurations and departure from local thermal equilibrium.

  7. Experimental study of the excitation of rhodium isomer in a plasma produced by a picosecond laser pulse

    SciTech Connect

    Afonin, V. I.; Kakshin, A. G.; Mazunin, A. V.

    2010-03-15

    Estimates and first experimental results on the excitation of a long-lived isomer state (E{sub m} = 39.756 keV, J{sup p} = 9/2{sup -}, and T{sub 1/2} = 56.114 min) of Rh{sup 103} nuclei under the action of X radiation in a hot solid-state-density rhodium plasma produced by a picosecond laser pulse in the SOKOL-P laser facility are presented.

  8. Saturation of the Xe III 109-nm laser using traveling-wave laser-produced-plasma excitation

    SciTech Connect

    Sher, M.H.; Macklin, J.J.; Young, J.F.; Harris, S.E.

    1987-11-01

    Construction and operation of a 109-nm, photoionization-pumped, single-pass laser in Xe III are described. The laser is pumped by soft x rays emitted from a laser-produced plasma in a traveling-wave geometry. Using a 3.5-J, 300-psec, 1064-nm laser pump pulse, a small-signal gain coefficient of 4.4/cm and a total small-signal gain of exp(40) were measured. The laser is fully saturated and produces an output energy of 20 micro J in a beam with 10-mrad divergence.

  9. Saturation of the Xe III 109-nm laser using traveling-wave laser-produced-plasma excitation

    SciTech Connect

    Sher, M.H.; Macklin, J.J.; Young, J.F.; Harris, S.E.

    1987-11-01

    We describe the construction and operation of a 109-nm, photoionization-pumped, single-pass laser in Xe III. The laser is pumped by soft x rays emitted from a laser-produced plasma in a traveling-wave geometry. Using a 3.5-J, 300-psec, 1064-nm laser pump pulse, we measure a small-signal gain coefficient of 4.4 cm/sup -1/ and a total small-signal gain of exp(40). The laser is fully saturated and produces an output energy of 20 ..mu..J in a beam with 10-mrad divergence.

  10. Saturation of the Xe III 109-nm laser using traveling-wave laser-produced-plasma excitation

    SciTech Connect

    Sher, M.H.; Macklin, J.J.; Young, J.F.; Harris, S.E.

    1987-11-01

    Construction and operation of a 109-nm, photoionization-pumped, single-pass laser in Xe III are described. The laser is pumped by soft x rays emitted from a laser-produced plasma in a traveling-wave geometry. Using a 3.5-J, 300-psec, 1064-nm laser pump pulse, a small-signal gain coefficient of 4.4/cm and a total small-signal gain of exp(40) were measured. The laser is fully saturated and produces an output of 20 microJ in a beam with 10-mrad divergence.

  11. Measurements of electron density and temperature profiles in plasma produced by Nike KrF laser for laser plasma instability research.

    PubMed

    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 × 10(15) W/cm(2). 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 × 10(21) cm(-3) with the density scale length of 120 μm along the plasma symmetry axis. The resulting n(e) and T(e) profiles are verified to be self-consistent with the measured quantities of the refracted probe light. PMID:26329186

  12. Numerical simulation of the coal combustion process initiated by a plasma source

    NASA Astrophysics Data System (ADS)

    Askarova, A. S.; Messerle, V. E.; Ustimenko, A. B.; Bolegenova, S. A.; Maksimov, V. Yu.

    2014-12-01

    Numerical experiments on the torch combustion of the coal dust prepared by a plasma-thermochemical treatment for combustion have been done using the method of three-dimensional simulation. It is shown that the plasma preparation of coal for combustion enables one to optimize the process, improve the conditions for inflammation and combustion and minimize the emissions of harmful substances.

  13. Plasma waves near Saturn: initial results from Voyager 1. Progress report

    SciTech Connect

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

    1981-01-31

    The Voyager 1 plasma wave instrument detected many familiar types of plasma waves during the encounter with Saturn, including ion-acoustic waves and electron plasma oscillations upstream of the bow shock, an intense burst of electrostatic noise at the shock, and chorus, hiss, electrostatic (n + 1/2)fg waves and UHR emissions in the inner magnetosphere. A clock-like Saturn rotational control of low-frequency radio emissions was observed, and evidence was obtained of possible control by the moon Dione. Strong plasma wave emissions were detected at the Titan encounter indicating the presence of a turbulent sheath extending around Titan, and UHR measurements of the electron density show the existence of a dense plume of plasma being carried downstream of Titan by the interaction with the rapidly rotating magnetosphere of Saturn.

  14. Plasma Spray-CVD: A New Thermal Spray Process to Produce Thin Films from Liquid or Gaseous Precursors

    NASA Astrophysics Data System (ADS)

    Gindrat, M.; Höhle, H.-M.; von Niessen, K.; Guittienne, Ph.; Grange, D.; Hollenstein, Ch.

    2011-06-01

    New dedicated coating processes which are based on the well-known LPPS™ technology but operating at lower work pressure (100 Pa) are being actively developed. These hybrid technologies contribute to improve the efficiencies in the turbine industry such as aero-engines and land-based gas turbines. They also have a great potential in the domain of new energy concepts in applications like Solid Oxide Fuel Cells, membranes, and photovoltaic with the adoption of new ways of producing coatings by thermal spray. Such processes include Plasma Spray-Thin Film (PS-TF) which gives the possibility to coat thin and dense layers from splats through a classical thermal spray approach but at high velocities (400-800 m/s) and enthalpy (8000-15000 kJ/kg). Plasma Spray-PVD (PS-PVD) which allows producing thick columnar-structured Thermal Barrier Coatings (100-300 μm) from the vapor phase with the employment of the high enthalpy gun and specific powder feedstock material. On the other hand, the Plasma Spray-CVD (PS-CVD) process uses modified conventional thermal spray components operated below 100 Pa which allows producing CVD-like coatings (<1-10 μm) at higher deposition rates using liquid or gaseous precursors as feedstock material. The advantages of such thermal spray-enhanced CVD processes are the high ionization degree and high throughput for the deposition of thin layers. In this article, we present an overview of the possibilities and limitations encountered while producing thin film coatings using liquid and gaseous precursors with this new type of low pressure plasma spray equipment and point out the challenges faced to obtain efficient injection and mixing of the precursors in the plasma jet. In particular, SiO x thin films from Hexamethyldisiloxane (HMDSO or C6H18OSi2) can be deposited on wafers at deposition rates of up to 35 nm/s at an efficiency of about 50%. The process was also used for producing metal oxide coatings (Al2O3, ZnO, and SnO2) by evaporating different metals in combination with an oxygen gas flow. The effect of process parameters on the deposition rate, coating build up, uniformity, and quality of the coatings are discussed. An overview of different potential applications of this new technology will be also presented.

  15. Multiple solutions in the theory of direct current glow discharges: Effect of plasma chemistry and nonlocality, different plasma-producing gases, and 3D modelling

    SciTech Connect

    Almeida, P. G. C.; Benilov, M. S.

    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.

  16. High-resolution imaging spectrometer for recording absolutely calibrated far ultraviolet spectra from laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Brown, Charles M.; Seely, John F.; Feldman, Uri; Holland, Glenn E.; Weaver, James L.; Obenschain, Steven P.; Kjornrattanawanich, Benjawan; Fielding, Drew

    2008-10-01

    An imaging spectrometer was designed and fabricated for recording far ultraviolet spectra from laser-produced plasmas with wavelengths as short as 155 nm. The spectrometer implements a Cassegrain telescope and two gratings in a tandem Wadsworth optical configuration that provides diffraction limited resolution. Spectral images were recorded from plasmas produced by the irradiation of various target materials by intense KrF laser radiation with 248 nm wavelength. Two pairs of high-resolution gratings can be selected for the coverage of two wavebands, one grating pair with 1800 grooves/mm and covering approximately 155-175 nm and another grating pair with 1200 grooves/mm covering 230-260 nm. The latter waveband includes the 248 nm KrF laser wavelength, and the former waveband includes the wavelength of the two-plasmon decay instability at 23 the KrF laser wavelength (165 nm). The detection media consist of a complementary metal oxide semiconductor imager, photostimulable phosphor image plates, and a linear array of 1 mm2 square silicon photodiodes with 0.4 ns rise time. The telescope mirrors, spectrometer gratings, and 1 mm2 photodiode were calibrated using synchrotron radiation, and this enables the measurement of the absolute emission from the laser-produced plasmas with temporal, spatial, and spectral resolutions. The spectrometer is capable of measuring absolute spectral emissions at 165 nm wavelength as small as 510-7 J/nm from a plasma source area of 0.37 mm2 and with 0.4 ns time resolution.

  17. High-resolution imaging spectrometer for recording absolutely calibrated far ultraviolet spectra from laser-produced plasmas

    SciTech Connect

    Brown, Charles M.; Seely, John F.; Feldman, Uri; Holland, Glenn E.; Weaver, James L.; Obenschain, Steven P.; Kjornrattanawanich, Benjawan; Fielding, Drew

    2008-10-15

    An imaging spectrometer was designed and fabricated for recording far ultraviolet spectra from laser-produced plasmas with wavelengths as short as 155 nm. The spectrometer implements a Cassegrain telescope and two gratings in a tandem Wadsworth optical configuration that provides diffraction limited resolution. Spectral images were recorded from plasmas produced by the irradiation of various target materials by intense KrF laser radiation with 248 nm wavelength. Two pairs of high-resolution gratings can be selected for the coverage of two wavebands, one grating pair with 1800 grooves/mm and covering approximately 155-175 nm and another grating pair with 1200 grooves/mm covering 230-260 nm. The latter waveband includes the 248 nm KrF laser wavelength, and the former waveband includes the wavelength of the two-plasmon decay instability at (2/3) the KrF laser wavelength (165 nm). The detection media consist of a complementary metal oxide semiconductor imager, photostimulable phosphor image plates, and a linear array of 1 mm{sup 2} square silicon photodiodes with 0.4 ns rise time. The telescope mirrors, spectrometer gratings, and 1 mm{sup 2} photodiode were calibrated using synchrotron radiation, and this enables the measurement of the absolute emission from the laser-produced plasmas with temporal, spatial, and spectral resolutions. The spectrometer is capable of measuring absolute spectral emissions at 165 nm wavelength as small as 5x10{sup -7} J/nm from a plasma source area of 0.37 mm{sup 2} and with 0.4 ns time resolution.

  18. Sharpening of the 6.8 nm peak in an Nd:YAG laser produced Gd plasma by using a pre-formed plasma

    NASA Astrophysics Data System (ADS)

    Tian, Yong; Song, Xiaolin; Xie, Zhuo; Gao, Jian; Dou, Yinping; Li, Bochao; Lin, Jingquan; Tomie, Toshihisa

    2016-03-01

    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.

  19. Expansion dynamics of ultrafast laser produced plasmas in the presence of ambient argon

    NASA Astrophysics Data System (ADS)

    Diwakar, P. K.; Harilal, S. S.; Hassanein, A.; Phillips, M. C.

    2014-10-01

    We investigated the expansion dynamics of fs laser ablated brass plasma in Ar at various pressure levels ranging from 10-5 Torr to atmospheric conditions using time-resolved and spectrally resolved two-dimensional imaging. Significant changes in plume morphology were noticed at varying pressure levels which included free expansion, spherical to cylindrical geometry changes, sharpening, and confinement. The temporal evolution of excited Cu and Zn species in the plume were imaged using narrow band-pass interference filters, and their hydrodynamic expansion features were compared. 2D imaging coupled with monochromatic line selection showed velocity differences, uneven distribution, and aspect ratio differences among the plume species. Plume morphological changes were found to be significant at intermediate pressure levels (˜10 Torr) where plasma emissivity was found to be maximum. The expansion features of plume were compared with various models and found to be generally in good agreement.

  20. Pressure Ionization and Line Merging in Strongly Coupled Plasmas Produced by 100-fs Laser Pulses

    SciTech Connect

    Nantel, M.; Ma, G.; Gu, S.; Cote, C.Y.; Itatani, J.; Umstadter, D.

    1998-05-01

    Time- and space-resolved extreme ultraviolet spectra of carbon plasmas, created with 100-fs laser pulses, are obtained with the novel technique of picosecond jitter-free streak-camera averaging. Spectroscopic diagnostics indicate electron densities and temperatures evolving from 10{sup 23} to 10{sup 21} cm{sup {minus}3} and 80 to 50eV, respectively, implying less than one particle in a Debye sphere at early times. The emission reveals conditions of extreme pressure ionization and line merging. Comparisons of the experimental spectra with numerical simulations validate the use of the Inglis-Teller limit for line merging, and confirm that pressure ionization models based on the Debye-Huckel potential are inapplicable in such strongly coupled plasmas. {copyright} {ital 1998} {ital The American Physical Society}

  1. Three-dimensional microscopy of laser-produced plasmas using third-harmonic generation

    SciTech Connect

    Sidorov-Biryukov, D A; Naumov, A N; Konorov, Stanislav O; Fedotov, Andrei B; Zheltikov, Aleksei M

    2000-12-31

    A three-dimensional microscopy of an optical-breakdown plasma based on third-harmonic generation (THG) is experimentally implemented. THG is shown to offer a universal method for three-dimensional microscopy of inhomogeneities of linear and nonlinear optical parameters of various media. Due to the nonlinear-optical character of this process, THG microscopy allows the transverse spatial resolution to be considerably improved as compared with conventional methods of microscopy. A high spatial resolution along the direction of probing is achieved due to the fact that the prohibition on THG in the regime of tight focusing is removed whenever inhomogeneities of linear and/or nonlinear optical parameters are probed by THG. (interaction of laser radiation with matter. laser plasma)

  2. Non-inductive plasma initiation and plasma current ramp-up on the TST-2 spherical tokamak

    NASA Astrophysics Data System (ADS)

    Takase, Y.; Ejiri, A.; Kakuda, H.; Oosako, T.; Shinya, T.; Wakatsuki, T.; Ambo, T.; Furui, H.; Hashimoto, T.; Hiratsuka, J.; Kasahara, H.; Kato, K.; Kumazawa, R.; Moeller, C. P.; Mutoh, T.; Nakanishi, A.; Nagashima, Y.; Saito, K.; Sakamoto, T.; Seki, T.; Sonehara, M.; Shino, R.; Togashi, H.; Watanabe, O.; Yamaguchi, T.

    2013-06-01

    Plasma current (Ip) 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 Ip ramp-up (to ˜10 kA) is most efficient with waves in the LH frequency range. Ip ramp-up to 15 kA was achieved with 60 kW of net RF power PRF 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 Ip, 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 Ip 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.

  3. Electron transport phenomena and dense plasmas produced by ultra-short pulse laser interaction

    SciTech Connect

    More, R.M.

    1994-07-08

    Recent experiments with femtosecond lasers provide a test bed for theoretical ideas about electron processes in hot dense plasmas. We briefly review aspects of electron conduction theory likely to prove relevant to femtosecond laser absorption. We show that the Mott-Ioffe-Regel limit implies a maximum inverse bremsstrahlung absorption of about 50% at temperatures near the Fermi temperature. We also propose that sheath inverse bremsstrahlung leads to a minimum absorption of 7-10% at high laser intensity.

  4. K-shell emission from 140 femtosecond laser-produced plasmas created from porous aluminum targets

    SciTech Connect

    Shepherd, R.; Price, D.; White, B.; Osterheld, A.; Walling, R.; Slaughter, D.; Stewart, R.; Gordan, S.

    1992-06-05

    The K-shell emission from flat and porous aluminum targets is used to infer the efficiency of creating a high temperature (>100eV), thermal plasma with 800 nm, 140 fs laser light. The K-shell emission from flat aluminum targets is fond to be significantly less than that of the porous targets, implying a lower temperature and less efficient coupling between the target and ultra-short pulse laser light.

  5. Expansion Dynamics of Ultrafast Laser Produced Plasmas in the Presence of Ambient Argon

    SciTech Connect

    Diwakar, P. K.; Harilal, Sivanandan S.; Hassanein, A.; Phillips, Mark C.

    2014-10-07

    In this paper, we report the emission features of fs laser ablated brass plasma plumes at various Ar background pressure levels ranging from vacuum to atmospheric conditions. Spectrally integrated 2D-imaging of plasma self-emission showed several interesting features at various pressure levels which consists of plume morphological changes, increase in persistence, confinement, and internal structures. Spatially resolved wavelength dispersed images of the plume were recorded for characterizing the spectral features at various pressure levels and also used for obtaining spatial distribution of Cu I and Zn I species in the plume, signal to noise ratios and fundamental parameters of the plasma; viz. temperature and density. The spatial evolution of excitation temperature and density showed significant changes at various ambient pressure levels and these results were correlated to morphological changes seen in the plume images. Optimum signal to background ratios for emission lines were observed in the moderate pressure range (~ 1-10 Torr). Optical time-of-flight profiles were used to study time evolution of various species in the plume and noticed oscillations at intermediate pressure levels. Possible mechanisms for observed changes in plume shape, optical emission intensity, and dual peak structures in time-of-flight profiles were discussed.

  6. Measurement of Neutrons Produced by Beam-Target Interactions via a Coaxial Plasma Accelerator

    NASA Astrophysics Data System (ADS)

    Cauble, Scott; Poehlmann, Flavio; Rieker, Gregory; Cappelli, Mark

    2011-10-01

    This poster presents a method to measure neutron yield from a coaxial plasma accelerator. Stored electrical energies between 1 and 19 kJ are discharged within a few microseconds across the electrodes of the coaxial gun, accelerating deuterium gas samples to plasma beam energies well beyond the keV energy range. The focus of this study is to examine the interaction of the plasma beam with a deuterated target by designing and fabricating a detector to measure neutron yield. Given the strong electromagnetic pulse associated with our accelerator, indirect measurement of neutrons via threshold-dependent nuclear activation serves as both a reliable and definitive indicator of high-energy particles for our application. Upon bombardment with neutrons, discs or stacks of metal foils placed near the deuterated target undergo nuclear activation reactions, yielding gamma-emitting isotopes whose decay is measured by a scintillation detector system. By collecting gamma ray spectra over time and considering nuclear cross sections, the magnitude of the original neutron pulse is inferred.

  7. Experimental observation of left polarized wave absorption near electron cyclotron resonance frequency in helicon antenna produced plasma

    SciTech Connect

    Barada, Kshitish K.; Chattopadhyay, P. K.; Ghosh, J.; Kumar, Sunil; Saxena, Y. C.

    2013-01-15

    Asymmetry in density peaks on either side of an m = +1 half helical antenna is observed both in terms of peak position and its magnitude with respect to magnetic field variation in a linear helicon plasma device [Barada et al., Rev. Sci. Instrum. 83, 063501 (2012)]. The plasma is produced by powering the m = +1 half helical antenna with a 2.5 kW, 13.56 MHz radio frequency source. During low magnetic field (B < 100 G) operation, plasma density peaks are observed at critical magnetic fields on either side of the antenna. However, the density peaks occurred at different critical magnetic fields on both sides of antenna. Depending upon the direction of the magnetic field, in the m = +1 propagation side, the main density peak has been observed around 30 G of magnetic field. On this side, the density peak around 5 G corresponding to electron cyclotron resonance (ECR) is not very pronounced, whereas in the m = -1 propagation side, very pronounced ECR peak has been observed around 5 G. Another prominent density peak around 12 G has also been observed in m = -1 side. However, no peak has been observed around 30 G on this m = -1 side. This asymmetry in the results on both sides is explained on the basis of polarization reversal of left hand polarized waves to right hand polarized waves and vice versa in a bounded plasma system. The density peaking phenomena are likely to be caused by obliquely propagating helicon waves at the resonance cone boundary.

  8. Detailed Hydrodynamic and X-Ray Spectroscopic Analysis of a Laser-Produced Rapidly-Expanding Aluminum Plasma

    SciTech Connect

    Chambers, D M; Glenzer, S H; Hawreliak, J; Wolfrum, E; Gouveia, A; Lee, R W; Marjoribanks, R S; Renner, O; Sondhauss, P; Topping, S; Young, P E; Pinto, P A; Wark, J S

    2001-04-03

    We present a detailed analysis of K-shell emission from laser-produced rapidly-expanding aluminum plasmas. This work forms part of a series of experiments performed at the Vulcan laser facility of the Rutherford Appleton Laboratory, UK. 1-D planar expansion was obtained by over-illuminating Al-microdot targets supported on CH plastic foils. The small size of the Al-plasma ensured high spatial and frequency resolution of the spectra, obtained with a single crystal spectrometer, two vertical dispersion variant double crystal spectrometers, and a vertical dispersion variant Johann Spectrometer. The hydrodynamic properties of the plasma were measured independently by spatially and temporally resolved Thomson scattering, utilizing a 4{omega} probe beam. This enabled sub- and super- critical densities to be probed relative to the 1{omega} heater beams. The deduced plasma hydrodynamic conditions are compared with those generated from the 1-D hydro-code Medusa, and the significant differences found in the electron temperature discussed. Synthetic spectra generated from the detailed term collisional radiative non-LTE atomic physics code Fly are compared with the experimental spectra for the measured hydrodynamic parameters, and for those taken from Medusa. Excellent agreement is only found for both the H- and He-like Al series when careful account is taken of the temporal evolution of the electron temperature.

  9. The Advantages of Non-Thermal Plasma for Detonation Initiation Compared with Spark Plug

    NASA Astrophysics Data System (ADS)

    Zheng, Dianfeng

    2016-02-01

    In this paper, the characteristics of detonation combustion ignited by AC-driven non-thermal plasma and spark plug in air/acetylene mixture have been compared in a double-tube experiment system. The two tubes had the same structure, and their closed ends were installed with a plasma generator and a spark plug, respectively. The propagation characteristics of the flame were measured by pressure sensors and ion probes. The experiment results show that, compared with a spark plug, the non-thermal plasma obviously broadened the range of equivalence ratio when the detonation wave could develop successfully, it also heightened the pressure value of detonation wave. Meanwhile, the detonation wave development time and the entire flame propagation time were reduced by half. All of these advantages benefited from the larger ignition volume when a non-thermal plasma was applied. supported by National Natural Science Foundation of China (No. 51176001)

  10. Initial observations of the Pioneer Venus orbiter solar wind plasma experiment

    NASA Technical Reports Server (NTRS)

    Wolfe, J.; Mihalov, J.; Collard, H.; Mckibbin, D.; Whitten, R.; Barnes, A.; Intriligator, D. S.

    1979-01-01

    The ionosphere, ionosheath, ionopause, and bow shock wave of Venus are characterized. Venus is found to have a well-defined strong standing bow shock wave. In the ionosheath, downstream from the shock, compressed and heated postshock plasma apparently interacts directly with the ionosphere. Plasma ion velocity deflections suggest that the ionopause has a blunt shape. The positions of the bow shock and ionopause are variable and appear to respond to changes in the external solar wind pressure.

  11. Initial measurement of the kinetic dust temperature of a weakly coupled dusty plasma

    SciTech Connect

    Williams, Jeremiah D.; Thomas, Edward Jr.

    2006-06-15

    Measurements of the velocity space distribution function of 2.9 {mu}m diameter silica particles in an argon dc glow discharge dusty plasma are made through the use of stereoscopic particle image velocimetry (stereo-PIV). These distribution functions are then used to determine the kinetic temperature of the dust component. These measurements show that the kinetic temperature of the dust component is significantly larger than the other plasma components (electrons, ions, and background neutrals)

  12. Initial Operation of the Miniaturized Inductively Heated Plasma Generator IPG6

    NASA Astrophysics Data System (ADS)

    Dropmann, Michael; Herdrich, Georg; Laufer, Rene; Koch, Helmut; Gomringer, Chris; Cook, Mike; Schmoke, Jimmy; Matthews, Lorin; Hyde, Truell

    2012-10-01

    In close collaboration between the Center for Astrophysics, Space Physics and Engineering Research (CASPER) at Baylor University, Texas, and the Institute of Space Systems (IRS) at the University of Stuttgart, Germany, two plasma wind tunnel facilities of similar type have been established using the inductively heated plasma source IPG6 which is based on proven IRS designs. The facility at Baylor University (IPG6-B) works at a frequency of 13.56 MHz and a maximum power of 15 kW. A vacuum pump of 160m^3/h in combination with a butterfly valve allows pressure control in a wide range. First experiments have been conducted with Air, O2 and N2 as working gases and volumetric flow rates of up to 14 L/min at pressures of a few 100 Pa, although pressures below 1 Pa are achievable at lower flow rates. The maximum tested electric power so far was 8 kW. Plasma powers and total pressures in the plasma jet have been obtained. In the near future the set up of additional diagnostics, the use of other gases (i.e. H2, He), and the integration of a dust particle accelerator are planned. The intended fields of research are basic investigation in thermo-chemistry and plasma radiation, space plasma environments and high heat fluxes e.g. in fusion devices or during atmospheric entry of spacecraft.

  13. PIC Simulation of RF Plasma Sheath Formation and Initial Validation of Optical Diagnostics using HPC Resources

    NASA Astrophysics Data System (ADS)

    Icenhour, Casey; Exum, Ashe; Martin, Elijah; Green, David; Smithe, David; Shannon, Steven

    2014-10-01

    The coupling of experiment and simulation to elucidate near field physics above ICRF antennae presents challenges on both the experimental and computational side. In order to analyze this region, a new optical diagnostic utilizing active and passive spectroscopy is used to determine the structure of the electric fields within the sheath region. Parallel and perpendicular magnetic fields with respect to the sheath electric field have been presented. This work focuses on the validation of these measurements utilizing the Particle-in-Cell (PIC) simulation method in conjunction with High Performance Computing (HPC) resources on the Titan supercomputer at Oak Ridge National Laboratory (ORNL). Plasma parameters of interest include electron density, electron temperature, plasma potentials, and RF plasma sheath voltages and thicknesses. The plasma is modeled utilizing the VSim plasma simulation tool, developed by the Tech-X Corporation. The implementation used here is a two-dimensional electromagnetic model of the experimental setup. The overall goal of this study is to develop models for complex RF plasma systems and to help outline the physics of RF sheath formation and subsequent power loss on ICRF antennas in systems such as ITER. This work is carried out with the support of Oak Ridge National Laboratory and the Tech-X Corporation.

  14. Low plasma ApoE levels are associated with smaller hippocampal size in the Alzheimer's disease neuroimaging initiative cohort.

    PubMed

    Teng, Edmond; Chow, Nicole; Hwang, Kristy S; Thompson, Paul M; Gylys, Karen H; Cole, Gregory M; Jack, Clifford R; Shaw, Leslie M; Trojanowski, John Q; Soares, Holly D; Weiner, Michael W; Apostolova, Liana G

    2015-01-01

    Apolipoprotein E (APOE) genotype is the strongest known genetic risk factor for sporadic Alzheimer's disease (AD), but the utility of plasma ApoE levels for assessing the severity of underlying neurodegenerative changes remains uncertain. Here, we examined cross-sectional associations between plasma ApoE levels and volumetric magnetic resonance imaging indices of the hippocampus from 541 participants [57 with normal cognition (NC), 375 with mild cognitive impairment (MCI), and 109 with mild AD] who were enrolled in the Alzheimer's Disease Neuroimaging Initiative. Across the NC and MCI groups, lower plasma ApoE levels were significantly correlated with smaller hippocampal size, as measured by either hippocampal volume or hippocampal radial distance. These associations were driven primarily by findings from carriers of an APOE ε4 allele and are consistent with prior reports that lower plasma ApoE levels correlate with greater global cortical Pittsburgh Compound B retention. In this high-risk group, plasma ApoE levels may represent a peripheral marker of underlying AD neuropathology in nondemented elderly individuals. PMID:25547651

  15. Properties of CO/sub 2/ laser produced long-life plasmas observed by x-ray spectroscopic methods

    SciTech Connect

    Daido, H.; Nishihara, K.; Mima, K.; Kitagawa, Y.; Nakai, S.; Yamanaka, C.; Hasegawa, A.

    1988-03-01

    We present the properties of shell confinement long-life plasmas produced by a CO/sub 2/ laser. The temperature measurement for parylene shell targets based on the x-ray spectroscopic method gives the electron temperature of more than 500 eV at the center of a 1-mm-diam target. An enchanced confinement time is obtained in a thick gold shell (100 ..mu..m thick) target coated internally with parylene. The duration of the x ray emitted from the hot core in a 3-mm-diam target of this type is 34 ns, while the laser pulse duration is 1 ns. The long duration of the x-ray manifests the hot core plasma lifetime; the observed duration presents a strong evidence of thermal insulation by the self-generated magnetic field.

  16. Laser-Produced Plasma Experiments and Particle in Cell Simulation to Study Thrust Conversion Processes in a Laser Fusion Rocket

    NASA Astrophysics Data System (ADS)

    Vchivkov, Konstantin V.; Nakashima, Hideki; Zakharov, Yuri P.; Esaki, Tomonori; Kawano, Toshihiko; Muranaka, Takanobu

    2003-10-01

    An experiment is conducted to study the thrust conversion process of a laser fusion rocket (LFR) in a scaled-down manner. The temporal evolution of laser-produced plasma clouds (LPC) expanding in a dipole magnetic field is examined and the thrust conversion efficiency is estimated. For comparative purposes, numerical analyses of plasma behaviour in a dipole magnetic field are also performed using a three-dimensional (3D) hybrid particle-in-cell (PIC) code. An overall good agreement between the experimental and simulation data is found. It is also found that a thrust conversion efficiency as high as 60% is possible in the scaled-down model considered here. The experiments will be very useful in developing LFR designs and testing the basic features of the large-scale simulative LFR experiments proposed for the National Ignition Facility (NIF).

  17. Study of self-generated magnetic fields in laser produced plasmas using a three-channel polaro-interferometer

    SciTech Connect

    Prasad, Y. B. S. R.; Barnwal, S.; Naik, P. A.; Kamath, M. P.; Joshi, A. S.; Kumbhare, S. R.; Gupta, P. D.; Bolkhovitinov, E. A.; Rupasov, A. A.

    2011-12-15

    Self-generated magnetic fields produced in laser plasmas at moderate laser intensities have been measured using a three-channel polaro-interferometer. The main elements of this device are two birefringent calcite wedges placed between two crossed polarizers. Using this device, the spatial profiles of (a) the rotation angle (polarometry), (b) the electron density (interferometry), and (c) the transmitted probe beam intensity (shadowgraphy) are recorded simultaneously using a digital camera with a large format CCD in a single laser shot. Magnetic fields of 2-4 MG had been estimated in aluminum plasma at laser intensities {approx}10{sup 13} W/cm{sup 2}. It is also possible to use this device in other configurations to get time resolved information.

  18. Copper, zinc, tin and lead in canned evaporated milk, produced in Lithuania: the initial content and its change at storage.

    PubMed

    Ramonaityte, D T

    2001-01-01

    The study has been carried out to elucidate what contents of heavy metals were typical for canned milk products--evaporated (TS 25.5-28.5%) sterilized milk and condensed sweetened milk, produced in Lithuania in the period 1983-1997. The influence of storage time upon the level of Sn, Pb, Cu and Zn in the products has also been determined. The results show that the most considerable changes occurred in Cu concentration, which gradually decreased from the maximum level in 1983-1985 (2.23 +/- 0.18 mg/kg) to the minimum level in the latest years (0.44 +/- 0.01 mg/kg). Such variation of copper content in canned milks can be closely connected with its changes in raw milk. Zinc content in canned milk products also was in good agreement with raw milk. The content of tin and lead in the canned products many times exceeded their concentration in raw milk and ranged from 28 +/- 2 and 0.093 +/- 0.005 to 114 +/- 4 and 0.29 +/- 0.01 mg/kg, respectively. It has been determined that the dependence of the concentration of tin and lead on the storage time of concentrated (or evaporated) sterilized milk is nearest to the parabolic, and in sweetened condensed milk to the exponential function, whereas the small increase of copper and zinc concentrations can be described by straight-line function. The functional dependence obtained enables one to predict the Sn and Pb level in canned evaporated milk products after storage and to foresee the safe initial concentration of these metals in freshly produced evaporated milk, assigned for storage. PMID:11212545

  19. Solid oxide fuel cell electrolytes produced via very low pressure suspension plasma spray and electrophoretic deposition

    NASA Astrophysics Data System (ADS)

    Fleetwood, James D.

    Solid oxide fuel cells (SOFCs) are a promising element of comprehensive energy policies due to their direct mechanism for converting the oxidization of fuel, such as hydrogen, into electrical energy. Both very low pressure plasma spray and electrophoretic deposition allow working with high melting temperature SOFC suspension based feedstock on complex surfaces, such as in non-planar SOFC designs. Dense, thin electrolytes of ideal composition for SOFCs can be fabricated with each of these processes, while compositional control is achieved with dissolved dopant compounds that are incorporated into the coating during deposition. In the work reported, sub-micron 8 mole % Y2O3-ZrO2 (YSZ) and gadolinia-doped ceria (GDC), powders, including those in suspension with scandium-nitrate dopants, were deposited on NiO-YSZ anodes, via very low pressure suspension plasma spray (VLPSPS) at Sandia National Laboratories' Thermal Spray Research Laboratory and electrophoretic deposition (EPD) at Purdue University. Plasma spray was carried out in a chamber held at 320 - 1300 Pa, with the plasma composed of argon, hydrogen, and helium. EPD was characterized utilizing constant current deposition at 10 mm electrode separation, with deposits sintered from 1300 -- 1500 C for 2 hours. The role of suspension constituents in EPD was analyzed based on a parametric study of powder loading, powder specific surface area, polyvinyl butyral (PVB) content, polyethyleneimine (PEI) content, and acetic acid content. Increasing PVB content and reduction of particle specific surface area were found to eliminate the formation of cracks when drying. PEI and acetic acid content were used to control suspension stability and the adhesion of deposits. Additionally, EPD was used to fabricate YSZ/GDC bilayer electrolyte systems. The resultant YSZ electrolytes were 2-27 microns thick and up to 97% dense. Electrolyte performance as part of a SOFC system with screen printed LSCF cathodes was evaluated with peak power densities as high as 520 mW/cm2 at 800 C for YSZ and 350 mW/cm 2 at 800 C for YSZ/GDC bilayer electrolytes.

  20. Photoconductive Detectors with Fast Temporal Response for Laser Produced Plasma Experiments

    SciTech Connect

    M. J. May, C. Halvorson, T. Perry, F. Weber, P. Young, C. Silbernagel

    2008-06-01

    Processes during laser plasma experiments typically have time scales that are less than 100 ps. The measurement of these processes requires X-ray detectors with fast temporal resolution. We have measured the temporal responses and linearity of several different Xray sensitive Photoconductive Detectors (PCDs). The active elements of the detectors investigated include both diamond (natural and synthetic) and GaAs crystals. The typical time responses of the GaAs PCDs are approximately 60 ps, respectively. Some characterizations using X-ray light from a synchrotron light source are presented.

  1. Photoconductive Detectors with Fast Temporal Response for Laser Produced Plasma Experiments.

    SciTech Connect

    May, M; Halvorson, C; Perry, T; Weber, F; Young, P; Silbernagel, C

    2008-05-06

    Processes during laser plasma experiments typically have time scales that are less than 100 ps. The measurement of these processes requires X-ray detectors with fast temporal resolution. We have measured the temporal responses and linearity of several different X-ray sensitive Photoconductive Detectors (PCDs). The active elements of the detectors investigated include both diamond (natural and synthetic) and GaAs crystals. The typical time responses of the GaAs PCDs are approximately 60 ps, respectively. Some characterizations using X-ray light from a synchrotron light source are presented.

  2. Plasma-produced phase-pure cuprous oxide nanowires for methane gas sensing

    SciTech Connect

    Cheng, Qijin Zhang, Fengyan; Yan, Wei; Randeniya, Lakshman; Ostrikov, Kostya

    2014-03-28

    Phase-selective synthesis of copper oxide nanowires is warranted by several applications, yet it remains challenging because of the narrow windows of the suitable temperature and precursor gas composition in thermal processes. Here, we report on the room-temperature synthesis of small-diameter, large-area, uniform, and phase-pure Cu{sub 2}O nanowires by exposing copper films to a custom-designed low-pressure, thermally non-equilibrium, high-density (typically, the electron number density is in the range of 10{sup 11}10{sup 13}?cm{sup ?3}) inductively coupled plasmas. The mechanism of the plasma-enabled phase selectivity is proposed. The gas sensors based on the synthesized Cu{sub 2}O nanowires feature fast response and recovery for the low-temperature (?140?C) detection of methane gas in comparison with polycrystalline Cu{sub 2}O thin film-based gas sensors. Specifically, at a methane concentration of 4%, the response and the recovery times of the Cu{sub 2}O nanowire-based gas sensors are 125 and 147?s, respectively. The Cu{sub 2}O nanowire-based gas sensors have a potential for applications in the environmental monitoring, chemical industry, mining industry, and several other emerging areas.

  3. Measurement of transient force produced by a propagating arc magnetohydrodynamic plasma actuator in quiescent atmospheric air

    NASA Astrophysics Data System (ADS)

    Choi, Young Joon; Sirohi, Jayant; Raja, Laxminarayan L.

    2015-10-01

    An experimental study was conducted on a magnetohydrodynamic plasma actuator consisting of two parallel, six inch long, copper electrodes flush mounted on an insulating ceramic plate. An electrical arc is generated by a  ∼1 kA current pulse at  ∼100 V across the electrodes. A self-induced Lorentz force drives the arc along the electrodes. The motion of the arc induces flow in the surrounding air through compression as well as entrainment, and generates a transient force, about  ∼4 ms in duration. Experiments were performed on a prototype actuator in quiescent atmospheric air to characterize the motion of the arc and the momentum transferred to the surrounding air. Measurements included transient force and total impulse generated by the actuator as well as the armature voltage and current. The arc shape and transit velocity were determined by high-speed imaging. A peak force of 0.4 N imparting an impulse of 0.68 mN-s was measured for a peak current of 1.2 kA. The force scaled with the square of the armature current and the impulse scaled linearly with the spent capacitor energy. The results provide insight into the mechanisms of body force generation and momentum transfer of a magnetohydrodynamic plasma actuator.

  4. Polyurethane coating with thin polymer films produced by plasma polymerization of diglyme

    NASA Astrophysics Data System (ADS)

    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.

  5. Direct observation of turbulent magnetic fields in hot, dense laser produced plasmas.

    PubMed

    Mondal, Sudipta; Narayanan, V; Ding, Wen Jun; Lad, Amit D; Hao, Biao; Ahmad, Saima; Wang, Wei Min; Sheng, Zheng Ming; Sengupta, Sudip; Kaw, Predhiman; Das, Amita; Kumar, G Ravindra

    2012-05-22

    Turbulence in fluids is a ubiquitous, fascinating, and complex natural phenomenon that is not yet fully understood. Unraveling turbulence in high density, high temperature plasmas is an even bigger challenge because of the importance of electromagnetic forces and the typically violent environments. Fascinating and novel behavior of hot dense matter has so far been only indirectly inferred because of the enormous difficulties of making observations on such matter. Here, we present direct evidence of turbulence in giant magnetic fields created in an overdense, hot plasma by relativistic intensity (10(18) W/cm(2)) femtosecond laser pulses. We have obtained magneto-optic polarigrams at femtosecond time intervals, simultaneously with micrometer spatial resolution. The spatial profiles of the magnetic field show randomness and their k spectra exhibit a power law along with certain well defined peaks at scales shorter than skin depth. Detailed two-dimensional particle-in-cell simulations delineate the underlying interaction between forward currents of relativistic energy "hot" electrons created by the laser pulse and "cold" return currents of thermal electrons induced in the target. Our results are not only fundamentally interesting but should also arouse interest on the role of magnetic turbulence induced resistivity in the context of fast ignition of laser fusion, and the possibility of experimentally simulating such structures with respect to the sun and other stellar environments. PMID:22566660

  6. Direct observation of turbulent magnetic fields in hot, dense laser produced plasmas

    PubMed Central

    Mondal, Sudipta; Narayanan, V.; Ding, Wen Jun; Lad, Amit D.; Hao, Biao; Ahmad, Saima; Wang, Wei Min; Sheng, Zheng Ming; Sengupta, Sudip; Kaw, Predhiman; Das, Amita; Kumar, G. Ravindra

    2012-01-01

    Turbulence in fluids is a ubiquitous, fascinating, and complex natural phenomenon that is not yet fully understood. Unraveling turbulence in high density, high temperature plasmas is an even bigger challenge because of the importance of electromagnetic forces and the typically violent environments. Fascinating and novel behavior of hot dense matter has so far been only indirectly inferred because of the enormous difficulties of making observations on such matter. Here, we present direct evidence of turbulence in giant magnetic fields created in an overdense, hot plasma by relativistic intensity (1018W/cm2) femtosecond laser pulses. We have obtained magneto-optic polarigrams at femtosecond time intervals, simultaneously with micrometer spatial resolution. The spatial profiles of the magnetic field show randomness and their k spectra exhibit a power law along with certain well defined peaks at scales shorter than skin depth. Detailed two-dimensional particle-in-cell simulations delineate the underlying interaction between forward currents of relativistic energy hot electrons created by the laser pulse and cold return currents of thermal electrons induced in the target. Our results are not only fundamentally interesting but should also arouse interest on the role of magnetic turbulence induced resistivity in the context of fast ignition of laser fusion, and the possibility of experimentally simulating such structures with respect to the sun and other stellar environments. PMID:22566660

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

    SciTech Connect

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

    2015-03-23

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

  8. Evaluation of the time-resolved EHD force produced by a plasma actuator by particle image velocimetry - a parametric study

    NASA Astrophysics Data System (ADS)

    Benard, N.; Caron, M.; Moreau, E.

    2015-10-01

    Surface plasma discharges, and more specifically dielectric barrier discharge, find several applications in aerodynamic due to their capability to produce a local flow at the dielectric wall. The present study proposes a numerical method to estimate the EHD force by using experimental velocity information. Here, this method is used in a parametric study and the obtained results are compared with force balance measurements. It is shown that the EHD volume force increases in space and in amplitude for increasing voltage and increasing AC frequency. Furthermore the force distribution expands in an homothetic manner.

  9. Dynamics and control of the expansion of finite-size plasmas produced in ultraintense laser-matter interactions

    SciTech Connect

    Peano, F.; Martins, J. L.; Fonseca, R. A.; Silva, L. O.; Coppa, G.; Peinetti, F.; Mulas, R.

    2007-05-15

    The strong influence of the electron dynamics provides the possibility of controlling the expansion of laser-produced plasmas by appropriately shaping the laser pulse. A simple irradiation scheme is proposed to tailor the explosion of large deuterium clusters, inducing the formation of shock structures, capable of driving nuclear fusion reactions. Such a scenario has been thoroughly investigated, resorting to two- and three-dimensional particle-in-cell simulations. Furthermore, the intricate dynamics of ions and electrons during the collisionless expansion of spherical nanoplasmas has been analyzed in detail using a self-consistent ergodic-kinetic model. This study clarifies the transition from hydrodynamic-like to Coulomb-explosion regimes.

  10. Dynamics and control of the expansion of finite-size plasmas produced in ultraintense laser-matter interactionsa)

    NASA Astrophysics Data System (ADS)

    Peano, F.; Martins, J. L.; Fonseca, R. A.; Silva, L. O.; Coppa, G.; Peinetti, F.; Mulas, R.

    2007-05-01

    The strong influence of the electron dynamics provides the possibility of controlling the expansion of laser-produced plasmas by appropriately shaping the laser pulse. A simple irradiation scheme is proposed to tailor the explosion of large deuterium clusters, inducing the formation of shock structures, capable of driving nuclear fusion reactions. Such a scenario has been thoroughly investigated, resorting to two- and three-dimensional particle-in-cell simulations. Furthermore, the intricate dynamics of ions and electrons during the collisionless expansion of spherical nanoplasmas has been analyzed in detail using a self-consistent ergodic-kinetic model. This study clarifies the transition from hydrodynamic-like to Coulomb-explosion regimes.

  11. Plasma Composition in Jupiter's Magnetosphere: Initial Results from the Solar Wind Ion Composition Spectrometer.

    PubMed

    Geiss, J; Gloeckler, G; Balsiger, H; Fisk, L A; Galvin, A B; Gliem, F; Hamilton, D C; Ipavich, F M; Livi, S; Mall, U; Ogilvie, K W; von Steiger, R; Wilken, B

    1992-09-11

    The ion composition in the Jovian environment was investigated with the Solar Wind Ion Composition Spectrometer on board Ulysses. A hot tenuous plasma was observed throughout the outer and middle magnetosphere. In some regions two thermally different components were identified. Oxygen and sulfur ions with several different charge states, from the volcanic satellite lo, make the largest contribution to the mass density of the hot plasma, even at high latitude. Solar wind particles were observed in all regions investigated. Ions from Jupiter's ionosphere were abundant in the middle magnetosphere, particularly in the highlatitude region on the dusk side, which was traversed for the first time. PMID:17776164

  12. Plasma composition in Jupiter's magnetosphere - Initial results from the Solar Wind Ion Composition Spectrometer

    NASA Technical Reports Server (NTRS)

    Geiss, J.; Gloeckler, G.; Balsiger, H.; Fisk, L. A.; Galvin, A. B.; Gliem, F.; Hamilton, D. C.; Ipavich, F. M.; Livi, S.; Mall, U.

    1992-01-01

    The ion composition in the Jovian environment was investigated with the Solar Wind Ion Composition Spectrometer on board Ulysses. A hot tenuous plasma was observed throughout the outer and middle magnetosphere. In some regions two thermally different components were identified. Oxygen and sulfur ions with several different charge states, from the volcanic satellite Io, make the largest contribution to the mass density of the hot plasma, even at high latitude. Solar wind particles were observed in all regions investigated. Ions from Jupiter's ionosphere were abundant in the middle magnetosphere, particularly in the high-latitude region on the dusk side, which was traversed for the first time.

  13. Characteristics of extreme ultraviolet emission from a discharge-produced potassium plasma for surface morphology application

    SciTech Connect

    Higashiguchi, Takeshi; Yugami, Noboru; Terauchi, Hiromitsu; Yatagai, Toyohiko; Sasaki, Wataru; D'Arcy, Rebekah; Dunne, Padraig; O'Sullivan, Gerry

    2010-03-29

    We have demonstrated a discharge-produced microplasma extreme ultraviolet source based on a pure potassium vapor. Potassium ions produced strong broadband emission around 40 nm with a bandwidth of 8 nm (full width at half-maximum). The current-voltage characteristics of microdischarge suggest that the source operates in a hollow cathode mode. By comparison with atomic structure calculations, the broadband emission is found to be primarily due to 3d-3p transitions in potassium ions ranging from K{sup 2+} to K{sup 4+}.

  14. Efficient multi-keV underdense laser-produced plasma radiators.

    PubMed

    Back, C A; Grun, J; Decker, C; Suter, L J; Davis, J; Landen, O L; Wallace, R; Hsing, W W; Laming, J M; Feldman, U; Miller, M C; Wuest, C

    2001-12-31

    Novel, efficient x-ray sources have been created by supersonically heating a large volume of Xe gas. A laser-induced bleaching wave quickly ionizes the high- Z gas, and the resulting plasma emits x rays. This method significantly improves the production of hard x rays because less energy is lost to kinetic energy and sub-keV x rays. The conversion efficiency of laser energy into L-shell radiation between 4-7 keV is measured at approximately 10%, an order of magnitude higher than efficiencies measured from solid disk targets. This higher flux enables material testing and backlighting in new regimes and scales well to future high-powered lasers. PMID:11800887

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

    DOEpatents

    White, Terry L; Paulauskas, Felix L; Bigelow, Timothy S

    2014-03-25

    A method for continuously processing carbon fiber including establishing a microwave plasma in a selected atmosphere contained in an elongated chamber having a microwave power gradient along its length defined by a lower microwave power at one end and a higher microwave power at the opposite end of the elongated chamber. The elongated chamber having an opening in each of the ends of the chamber that are adapted to allow the passage of the fiber tow while limiting incidental gas flow into or out of said chamber. A continuous fiber tow is introduced into the end of the chamber having the lower microwave power. The fiber tow is withdrawn from the opposite end of the chamber having the higher microwave power. The fiber to is subjected to progressively higher microwave energy as the fiber is being traversed through the elongated chamber.

  16. Optimizing conversion efficiency and reducing ion energy in a laser-produced Gd plasma

    SciTech Connect

    Cummins, Thomas; Li Bowen; O'Gorman, Colm; Dunne, Padraig; Sokell, Emma; O'Sullivan, Gerry; Otsuka, Takamitsu; Yugami, Noboru; Higashiguchi, Takeshi; Jiang Weihua; Endo, Akira

    2012-02-06

    We have demonstrated an efficient extreme ultraviolet (EUV) source at 6.7 nm by irradiating Gd targets with 0.8 and 1.06 {mu}m laser pulses of 140 fs to 10 ns duration. Maximum conversion efficiency of 0.4% was observed within a 0.6% bandwidth. A Faraday cup observed ion yield and time of flight signals for ions from plasmas generated by each laser. Ion kinetic energy was lower for shorter pulse durations, which yielded higher electron temperatures required for efficient EUV emission, due to higher laser intensity. Picosecond laser pulses were found to be the best suited to 6.7 nm EUV source generation.

  17. Three-dimensional extreme ultraviolet emission from a droplet-based laser-produced plasma

    SciTech Connect

    Giovannini, A. Z.; Abhari, Reza S.

    2013-07-21

    The emission of extreme ultraviolet radiation in a 2% bandwidth centered at 13.5 nm (in-band) is measured in one hemisphere. The targets of the laser are tin droplets. In-band emission is measured at angles from the laser axis larger than 120 Degree-Sign . Analytical models representing the physical processes are developed and calibrated with the experimental data. In the models two assumptions are investigated, isentropic and isothermal 2D-axisymmetric expansion. The parameters of the models are the density distribution of the plasma and the location where the EUV emission is centered. The parameters are inferred by the calibration of the models with the experimental data. The predictions of the models are validated with experiments where slab targets were used.

  18. Basic study on discharge induction by laser-produced plasmas in atmospheric air

    SciTech Connect

    Tsuji, T.; Honda, C.; Uchiumi, M.; Tanaka, T.; Muraoka, K.; Takuma, T.; Kinoshita, F.; Katahira, O.; Akazaki, M.

    1996-05-01

    To clarify the characteristics of the discharge induction against the delay time of impulse application with a long gap/1/, the electron and neutral particle density in the plasma were measured. The electron density was about 10{sup 23} m{sup {minus}3} at 10 {mu}s after firing the laser and then gradually decreases in several tens of microseconds. The rarefied air region of lower neutral particle density takes a spherical shell profile in later stages after firing the laser. From the experiments of the laser-induced discharge, it seems that the discharge induction was greatly influenced by the electron attachment to oxygen molecules and rarefied region of the neutral particle density. {copyright} {ital 1996 American Institute of Physics.}

  19. Novel analysis system using surface desorption stimulated by VUV photons from laser-produced plasma

    NASA Astrophysics Data System (ADS)

    Katto, Masahito; Kaku, Masanori; Kubodera, Shoichi; Yokotani, Atushi; Miyabayashi, Nobuyoshi; Sasaki, Wataru

    2010-09-01

    We proposed and developed a novel surface analysis system using vacuum ultraviolet (VUV) photons. When the VUV photons were irradiated on the material surface, surface desorption was stimulated. The desorbed species were analyzed by the mass spectrometer. First, we studied the decomposition process induced by VUV photons from excimer lamps. We found that the different photon energy resulted in the different time dependence of the fragments signals even if the materials had similar chemical construction. It suggested that the identification of the materials should be possible by tracing the decomposition process. We developed an analyzing system, called "Photo-Stimulated Desorption (PSD) mass spectrometer" using a broadband VUV radiation from the Ar plasma excited by a Q-switched Nd:YAG laser. The desorbed species were analyzed by the quadrupole mass spectrometer. This PSD system was useful surface analysis tool not only for the semiconductor but also plastics, which is easily affected by heat.

  20. Processes for forming exoergic structures with the use of a plasma and for producing dense refractory bodies of arbitrary shape therefrom

    DOEpatents

    Holt, J. Birch (San Jose, CA); Kelly, Michael D. (West Alexandria, OH)

    1990-01-01

    Plasma spraying methods of forming exoergic structures and coatings, as well as exoergic structures produced by such methods, are provided. The methods include the plasma spraying of reactive exoergic materials that are capable of sustaining a combustion synthesis reaction onto a flat substrate or into molds of arbitrary shape and igniting said plasma sprayed materials, either under an inert gas pressure or not, to form refractory materials of varying densities and of varying shapes.