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Sample records for petawatt laser-solid interactions

  1. Proton Beam Focusing and Heating in Petawatt Laser-Solid Interactions

    SciTech Connect

    Snavely, R A; Gu, P; King, J; Hey, D; Akli, K; Zhang, B B; Freeman, R; Hatchett, S; Key, M H; Koch, J; Langdon, A B; Lasinsky, B; MacKinnon, A; Patel, P; Town, R; Wilks, S; Stephens, R; Tsutsumi, T; Chen, Z; Yabuuchi, T; Kurahashi, T; Sato, T; Adumi, K; Toyama, Y; Zheng, J; Kodama, R; Tanaka, K A; Yamanaka, T

    2003-08-13

    It has recently been demonstrated that femtosecond-laser generated proton beams may be focused. These protons, following expansion of the Debye sheath, emit off the inner concave surface of hemispherical shell targets irradiated at their outer convex pole. The sheath normal expansion produces a rapidly converging proton beam. Such focused proton beams provide a new and powerful means to achieve isochoric heating to high temperatures. They are potentially important for measuring the equation of state of materials at high energy density and may provide an alternative route to fast ignition. We present the first results of proton focusing and heating experiments performed at the Petawatt power level at the Gekko XII Laser Facility at ILE Osaka Japan. Solid density Aluminum slabs are placed in the proton focal region at various lengths. The degree of proton focusing is measured via XUV imaging of Planckian emission of the heated zone. Simultaneous with the XUV measurement a streaked optical imaging technique, HISAK, gave temporal optical emission images of the focal region. Results indicate excellent coupling between the laser-proton conversion and subsequent heating.

  2. High energy electrons, positrons and photonuclear reactions in petawatt laser-solid experiments

    SciTech Connect

    Cowan, T E; Hunt, A W; Johnson, J; Perry, M D; Fountain, W; Hatchett, S; Key, M H; Kuehl, T; Parnell, T; Pennington, D M; Phillips, T W; Roth, M; Takahashi, Y; Wilks, S C

    1999-09-09

    The Petawatt laser at LLNL has opened a new regime of high-energy laser-matter interactions in which the quiver motion of plasma electrons is fully relativistic with energies extending well above the threshold for nuclear processes. We have observed that, in addition to the large flux of several MeV electrons ponderomotively expelled from the ultra-intense laser focus, there is a high energy component of electrons extending to -100 MeV, apparently from relativistic self-focusing and plasma acceleration in the underdense pre-formed plasma. The generation of hard bremsstrahlung cascade as these electrons traverse the solid target material, and the resulting photo-nuclear reactions, nuclear fission, and positron-electron pair production are described.

  3. Dissipative Structures At Laser-Solid Interactions

    NASA Astrophysics Data System (ADS)

    Nanai, Laszlo

    1989-05-01

    The questions which are discussed in this lecture refer to one of sections of laser-solid interactions, namely: to formation of different dissipative structures on the surface of metals and semiconductors when they are irradiated by intensive laser light in chemically active media (f.e.air). Some particular examples of the development at different spatial and time instabilities, periodic and stochastic structures, auto-wave processes are present-ed using testing materials vanadium metal and semiconducting V205 single crystals and light sources: cw and pulsed CO2 and YAG lasers.

  4. High-energy electron, positron, ion and nuclear spectroscopy in ultra-intense laser-solid experiments on the petawatt

    SciTech Connect

    Brown, C; Christl, M; Cowan, T E; Fakahashi, Y; Fountain, W; Hatchett, S; Henry, E A; Hunt, A W; Johnson, J; Key, M; Kuehl, T; Moody, J; Moran, M; Patterson, W S; Pennington, D M; Perry, M D; Phillips, T C; Roth, M; Sefcik, J; Singh, M; Snavely, R; Syoyer, M; Wilks, S C; Young, P

    1999-09-16

    The LLNL Petawatt Laser has achieved focused intensities up to 6 x 20 W/cm{sup 2}, which has opened a new, higher energy regime of relativistic laser-plasma interactions in which the quiver energies of the target electrons exceed the energy thresholds for many nuclear phenomena. We will describe recent experiments in which we have observed electrons accelerated to 100 MeV, photo-nuclear fission, and positron-electron pair creation.

  5. HOT ELECTRON ENERGY DISTRIBUTIONS FROM ULTRA-INTENSE LASER SOLID INTERACTIONS

    SciTech Connect

    Chen, H; Wilks, S C; Kruer, W L; Moon, S; Patel, N; Patel, P K; Shepherd, R; Snavely, R

    2005-12-08

    We present experimental data of electron energy distributions from ultra-intense (>10{sup 19} W/cm{sup 2}) laser-solid interactions using the Rutherford Appleton Laboratory Vulcan petawatt laser. These measurements were made using a CCD-based magnetic spectrometer. We present details on the distinct effective temperatures that were obtained for a wide variety of targets as a function of laser intensity. It is found that as the intensity increases from 10{sup 17} W/cm{sup 2} to 10{sup 19} W/cm{sup 2}, a 0.4 dependence on the laser intensity is found. Between 10{sup 19} W/cm{sup 2} and 10{sup 20} W/cm{sup 2}, a gradual rolling off of temperature with intensity is observed.

  6. HOT ELECTRON ENERGY DISTRIBUTIONS FROM ULTRA-INTENSE LASER SOLID INTERACTIONS

    SciTech Connect

    Chen, H; Wilks, S C; Kruer, W; Patel, P; Shepherd, R

    2008-10-08

    Measurements of electron energy distributions from ultra-intense (>10{sup 19} W/cm{sup 2}) laser-solid interactions using an electron spectrometer are presented. These measurements were performed on the Vulcan petawatt laser at Rutherford Appleton Laboratory and the Callisto laser at Lawrence Livermore National Laboratory. The effective hot electron temperatures (T{sub hot}) have been measured for laser intensities (I{lambda}{sup 2}) from 10{sup 18} W/cm{sup 2} {micro}m{sup 2} to 10{sup 21} W/cm{sup 2} {micro}m{sup 2} for the first time, and T{sub hot} is found to increase as (I{lambda}{sup 2}){sup 0.34} {+-} 0.4. This scaling agrees well with the empirical scaling published by Beg et al. (1997), and is explained by a simple physical model that gives good agreement with experimental results and particle-in-cell simulations.

  7. Characterization of the backscattered radiation from petawatt laser matter interactions

    SciTech Connect

    Vernon, Edwina D.; Musgrave, Ian O.; Green, James; Heathcote, Robert; Lancaster, Kate L.; Mendes, Cedric; Hawkes, Steve J.; Hernandez-Gomez, Cristina; Pepler, Dave A

    2008-06-20

    The development of high peak power and energy laser systems require the assurance that any backscattered radiation will not lead to damage of the laser system. We present the characterization of the backscattered radiation for different target types and conditions at petawatt power levels and intensities (>10{sup 20}W/cm{sup 2}). We observe that radiation is generated between 700 and 900 nm, as well as the expected self emission and laser fundamental. The percentage of the incident light backscattered reduces as a function of the incident energy and is typically <1% for petawatt laser interactions.

  8. Low-emittance monoenergetic electron and ion beams from ultra-intense laser-solid interactions

    SciTech Connect

    Cowan, T E; Roth, M; Allen, M M; Johnson, J; Hatchett, S P; Le Sage, G P; Wilks, S C

    2000-03-03

    Recent experiments at the LLNL Petawatt Laser have demonstrated the generation of intense, high energy beams of electrons and ions from the interaction of ultra-intense laser light with solid targets. Focused laser intensities as high as 6 x 10{sup 20} W/cm{sup 2} are achieved, at which point the quiver energies of the target electrons extend to {approx}10 MeV. In this new, fully relativistic regime of laser-plasma interactions, nuclear processes become important and nuclear techniques are required to diagnose the high-energy particle production. In recent experiments we have observed electrons accelerated to 100 MeV, up to 60 MeV brehmsstrahlung generation, photo-nuclear fission and positron-electron pair creation. We also have observed monoenergetic jets of electrons having sufficiently small emittance to be interesting as a laser-accelerated beam, if the production mechanism could be understood and controlled. The huge flux of multi-MeV ponderomotively accelerated electrons produced in the laser-solid interaction is also observed to accelerate contaminant ions from the rear surface of the solid target up to 50 MeV. We describe spectroscopic measurements which reveal intense monoenergetic beam features in the proton energy spectrum. The total spectrum contains >10{sup 13} protons, while the monoenergetic beam pulses contain {approx}1 nC of protons, and exhibits a longitudinal and transverse emittance smaller than conventional RF proton accelerator beams.

  9. Interaction physics of multipicosecond Petawatt laser pulses with overdense plasma.

    PubMed

    Kemp, A J; Divol, L

    2012-11-01

    We study the interaction of intense petawatt laser pulses with overdense plasma over several picoseconds, using two- and three-dimensional kinetic particle simulations. Sustained irradiation with non-diffraction-limited pulses at relativistic intensities yields conditions that differ qualitatively from what is experimentally available today. Nonlinear saturation of laser-driven density perturbations at the target surface causes recurrent emissions of plasma, which stabilize the surface and keep absorption continuously high. This dynamics leads to the acceleration of three distinct groups of electrons up to energies many times the laser ponderomotive potential. We discuss their energy distribution for applications like the fast-ignition approach to inertial confinement fusion. PMID:23215393

  10. Review of laser-solid interaction and its possibilities for space propulsion

    NASA Technical Reports Server (NTRS)

    Harstad, K. G.

    1972-01-01

    Literature on laser-solid interaction is surveyed and the important regimes of this process are delineated. This information is used to discuss the possibility of a laser induced ablation thruster. It is concluded that such a thruster may be feasible if a sufficiently high intensity, high frequency laser beam is available and that further study of interaction is needed.

  11. Integrated Laser-Target Interaction Experiments on the RAL Petawatt Laser

    SciTech Connect

    Patel, P K; Key, M H; Mackinnon, A J; Berry, R; Borghesi, M; Chambers, D M; Chen, H; Clarke, R; Damian, C; Eagleton, R; Freeman, R; Glenzer, S; Gregori, G; Heathcote, R; Hey, D; Izumi, N; Kar, S; King, J; Nikroo, A; Niles, A; Park, H S; Pasley, J; Patel, N; Shepherd, R; Snavely, R A; Steinman, D; Stoeckl, C; Storm, M; Town, R; Van Maren, R; Theobald, W; Wilks, S C; Zhang, B

    2006-10-11

    Since the construction of the first Petawatt laser on the Nova laser facility at Lawrence Livermore National Laboratory we are witnessing the emergence of similar Petawatt-class laser systems at laboratories all around the world. This new generation of lasers, able to deliver several hundred joules of energy in a sub-picosecond pulse, has enabled a host of new discoveries to be made and continues to provide a valuable tool to explore new regimes in relativistic laser-plasma physics--encompassing high energy X-rays and -rays, relativistic electrons, intense ion beams, and superstrong magnetic fields. The coupling in the near-future of multi-kiloJoule Petawatt-class lasers with large-scale fusion lasers.including the NIF and Omega EP (US), LIL (France), and FIREX (Japan)--will further expand opportunities in fast ignition, high energy X-ray radiography, and high energy density physics research. The 500 J Petawatt laser at the Rutherford Appleton Laboratory is currently the highest energy short-pulse laser in the world. In this paper we describe a recent experimental campaign carried out on the facility. The campaign, performed by a large collaborative team from eight different laboratories, was designed to study a variety of relativistic laser-interaction phenomena including laser absorption, fast electron transport, proton heating, and high-brightness x-ray generation. The wide scope of the experiment necessitated the deployment of a very large set of diagnostics--in total twenty-five separate instruments. In order to obtain the most comprehensive set of measurements all twenty-five diagnostics were fielded simultaneously on every shot.

  12. Studies of the Relativistic Electron Source and Related Phenomena in Petawatt Laser Matter Interactions

    SciTech Connect

    Key, M.H.; Campbell, E.M.; Cowen, T.E.; Hatchett, S.P.; Jenary, E.A.; Koch, J.A.; Langson, A.B.; Lasinski, B.F.; Lee, W.; Mackinnon, A.; Offenberger, A.A.; Perry, M.D.; Phillips, T.J.; Roth, M.; Sangster, T.C.; Singh, M.S.; Snavely, R.; Stoyer, M.A.; Wilks, S.C.; Yaskire, K.Y.

    1999-11-11

    The interaction of laser radiation with solid targets at 1 petawatt power and intensity up to 3 x 10{sup 20} Wcm{sup -2} has been studied with emphasis on relativistic electrons and high-energy ions. Secondary effects including Bremsstrahlung radiation, nuclear interactions and heating have been characterized. A collimated beam of protons with up to 55 MeV energy is emitted normal to the rear surface of thin targets and its characteristics and origin are discussed. The significance of the data for radiography, fast ignition and proton beam applications is summarized.

  13. Studies of the relativistic electron source and related phenomena in Petawatt Laser matter interactions

    SciTech Connect

    Key, M H; Campbell, E M; Cowan, T E; Hatchett, S P; Henry, E A; Koch, J A; Landgon, A B; Lasinski, B F; Lee, R W; MacKinnon, A; Offenberger, A; Pennington, D M; Perry, M D; Sangster, T C; Yasuike, K; Snavely, R; Roth, M; Phillips, T W; Stoyer, M A; Wilks, S C; Singh, M S

    1999-09-27

    The interaction of laser radiation with solid targets at 1 petawatt power and intensity up to 3x10{sup 20} Wcm{sup -2} has been studied with emphasis on relativistic electrons and high energy ions. Secondary effects including Bremsstrahlung radiation, nuclear interactions and heating have been characterized. A collimated beam of protons with up to 55 MeV energy is emitted normal to the rear surface of thin targets and its characteristics and origin are discussed. The significance of the data for radiography, fast ignition and proton beam applications is summarized.

  14. Sub GV/cm terahertz radiation from relativistic laser-solid interactions via coherent transition radiation

    NASA Astrophysics Data System (ADS)

    Ding, W. J.; Sheng, Z. M.

    2016-06-01

    Broadband terahertz (THz) radiation with extremely high peak power, generated by the interaction of a femtosecond laser with a thin solid target, has been investigated via particle-in-cell simulations. The spatial (angular) and temporal profiles of the THz radiation reveal that it is caused by the coherent transition radiation emitted when laser-produced hot electrons pass through the front or rear surface of the target. Dependence of the THz radiation on laser and target parameters is studied; it is shown to have a strong correlation with hot electron production. The THz radiation conversion efficiency can be as high as a few times 10-3. This radiation is not only a potentially high power THz source, but may also be used as a unique diagnostic of hot electron generation and transport in relativistic laser-solid interactions.

  15. Hot electron production in laser solid interactions with a controlled pre-pulse

    SciTech Connect

    Culfa, O.; Tallents, G. J.; Wagenaars, E.; Ridgers, C. P.; Dance, R. J.; Rossall, A. K.; Woolsey, N. C.; Gray, R. J.; McKenna, P.; Brown, C. D. R.; James, S. F.; Hoarty, D. J.; Booth, N.; Robinson, A. P. L.; Lancaster, K. L.; Pikuz, S. A.; Faenov, A. Ya.; Kampfer, T.; Schulze, K. S.; Uschmann, I.

    2014-04-15

    Hot electron generation plays an important role in the fast ignition approach to inertial confinement fusion (ICF) and other applications with ultra-intense lasers. Hot electrons of temperature up to 10–20 MeV have been produced by high contrast picosecond duration laser pulses focussed to intensities of ∼10{sup 20} W cm{sup −2} with a deliberate pre-pulse on solid targets using the Vulcan Petawatt Laser facility. We present measurements of the number and temperature of hot electrons obtained using an electron spectrometer. The results are correlated to the density scale length of the plasma produced by a controlled pre-pulse measured using an optical probe diagnostic. 1D simulations predict electron temperature variations with plasma density scale length in agreement with the experiment at shorter plasma scale lengths (<7.5μm), but with the experimental temperatures (13–17 MeV) dropping below the simulation values (20–25 MeV) at longer scale lengths. The experimental results show that longer interaction plasmas produced by pre-pulses enable significantly greater number of hot electrons to be produced.

  16. Laser-solid interaction and dynamics of the laser-ablated materials

    SciTech Connect

    Chen, K.R.; Leboeuf, J.N.; Geohegan, D.B.; Wood, R.F.; Donato, J.M.; Liu, C.L.; Puretzky, A.A.

    1995-07-01

    Rapid transformations through the liquid and vapor phases induced by laser-solid interactions are described by the authors` thermal model with the Clausius-Clapeyron equation to determine the vaporization temperature under different surface pressure condition. Hydrodynamic behavior of the vapor during and after ablation is described by gas dynamic equations. These two models are coupled. Modeling results show that lower background pressure results lower laser energy density threshold for vaporization. The ablation rate and the amount of materials removed are proportional to the laser energy density above its threshold. The authors also demonstrate a dynamic source effect that accelerates the unsteady expansion of laser-ablated material in the direction perpendicular to the solid. A dynamic partial ionization effect is studied as well. A self-similar theory shows that the maximum expansion velocity is proportional to c{sub s}{alpha}, where 1 {minus} {alpha} is the slope of the velocity profile. Numerical hydrodynamic modeling is in good agreement with the theory. With these effects, {alpha} is reduced. Therefore, the expansion front velocity is significantly higher than that from conventional models. The results are consistent with experiments. They further study how the plume propagates in high background gas condition. Under appropriate conditions, the plume is slowed down, separates with the background, is backward moving, and hits the solid surface. Then, it splits into two parts when it rebounds from the surface. The results from the modeling will be compared with experimental observations where possible.

  17. Hard x-ray production from high intensity laser solid interactions

    SciTech Connect

    Sefcik, J. A., LLNL

    1998-06-03

    Intense laser (> 10{sup 21} W/cm{sup 2}) driven hard x-ray sources offer a new alternative to conventional electron accelerator bremsstrahlung sources. These laser driven sources offer considerable simplicity in design and cost advantage for multiple axis views and have the potential for much higher spatial and temporal resolution than is achievable with accelerator sources We have begun a series of experiments using the Petawatt Laser system at LLNL to determine the potential of these sources for radiography applications Absolutely calibrated spectra extending to 20 MeV and high resolution radiographs through a {rho}r{>=}150 gm/cm{sup 2} have been obtained The physics of these sources and the scaling relationships and laser technology required to provide the dose levels necessary for radiography applications will be discussed Diagnostics of the laser produced electrons and photons will be addressed

  18. Electron, Photon, and Ion Beams from the Relativistic Interaction of Petawatt Laser Pulses with Solid Targets

    SciTech Connect

    Hatchett, S.P.; Brown, C.G.; Cowan, T.E.; Henry, E.A.; Johnson, J.; Key, M.H.; Koch, J.A.; Langdon, A.B.; Lasinski, B.F.; Lee, R.W.; Mackinnon, A.J.; Pennington, D.M.; Perry, M.D.; Phillips, T.W.; Roth, M.; Sangster, T.C.; Singh, M.S.; Snavely, R.A.; Stoyer, M.A.; Wilks, S.C.; Yasuike, K.

    1999-11-12

    In our Petawatt laser experiments several hundred joules of 1 {micro}m laser light in 0.5-5.0 ps pulses with intensities up to 3 x 10{sup 20}Wcm{sup -2} were incident on solid targets producing a strongly relativistic interaction. The energy content, spectra, and angular patterns of the photon, electron, and ion radiations were diagnosed in a number of ways, including several novel (to laser physics) nuclear activation techniques. From the beamed bremsstrahlung we infer that about 40-50% of the laser energy is converted to broadly beamed hot electrons. Their direction centroid varies from shot to shot, but the beam has a consistent width. Extraordinarily luminous ion beams almost precisely normal to the rear of various targets are seen--up to 3 x 10{sup 13} protons with kT{sub ion} {approx} several MeV representing {approx}6% of the laser energy. We observe ion energies up to at least 55 MeV. The ions appear to originate from the rear target surfaces. The edge of the ion beam is very sharp, and collimation increases with ion energy. At the highest energies, a narrow feature appears in the ion spectra, and the apparent size of the emitting spot is smaller than the full back surface area. Any ion emission from the front of the targets is much less than from the rear and is not sharply beamed. The hot electrons generate a Debye sheath with electrostatic fields of order MV per micron which apparently accelerate the ions.

  19. Electron, photon, and ion beams from the relativistic interaction of Petawatt laser pulses with solid targets

    SciTech Connect

    Hatchett, Stephen P.; Brown, Curtis G.; Cowan, Thomas E.; Henry, Eugene A.; Johnson, Joy S.; Key, Michael H.; Koch, Jeffrey A.; Langdon, A. Bruce; Lasinski, Barbara F.; Lee, Richard W.

    2000-05-01

    In recent Petawatt laser experiments at Lawrence Livermore National Laboratory, several hundred joules of 1 {mu}m laser light in 0.5-5.0-ps pulses with intensities up to 3x10{sup 20} W cm{sup -2} were incident on solid targets and produced a strongly relativistic interaction. The energy content, spectra, and angular patterns of the photon, electron, and ion radiations have all been diagnosed in a number of ways, including several novel (to laser physics) nuclear activation techniques. About 40%-50% of the laser energy is converted to broadly beamed hot electrons. Their beam centroid direction varies from shot to shot, but the resulting bremsstrahlung beam has a consistent width. Extraordinarily luminous ion beams (primarily protons) almost precisely normal to the rear of various targets are seen--up to 3x10{sup 13} protons with kT{sub ion}{approx}several MeV representing {approx}6% of the laser energy. Ion energies up to at least 55 MeV are observed. The ions appear to originate from the rear target surfaces. The edge of the ion beam is very sharp, and collimation increases with ion energy. At the highest energies, a narrow feature appears in the ion spectra, and the apparent size of the emitting spot is smaller than the full back surface area. Any ion emission from the front of the targets is much less than from the rear and is not sharply beamed. The hot electrons generate a Debye sheath with electrostatic fields of order MV per micron, which apparently accelerate the ions. (c) 2000 American Institute of Physics.

  20. Investigation of resistive guiding of fast electrons in ultra-intense laser-solid interactions

    NASA Astrophysics Data System (ADS)

    Green, James; Booth, Nicola; Robinson, Alex; Lancaster, Kate; Murphy, Chris; Ridgers, Chris

    2015-11-01

    A key issue in realising the development of a number of high-intensity laser-plasma applications is the critical problem of fast electron divergence. Previous experimental measurements have indicated that the electron divergence angle is considerable at relativistic intensities (> 1018 Wcm-2) and that self-pinching of the electron beam will not be sufficient to produce the collimated propagation that is required for applications such as WDM studies or bright, short-pulse X-ray sources. A number of concepts have been proposed to improve fast electron collimation, with one promising approach being to exploit resistivity gradients inside targets to magnetically guide fast electrons. Here we present experimental work using a novel conical target geometry that uses a high/low Z interface to produce such guiding. A range of target designs have been tested using the Vulcan Petawatt laser to investigate improvements in fast electron transport and collimation. Preliminary results will be presented from a number of complementary diagnostics in order to assess the degree and robustness of the focusing mechanism.

  1. Measurement of the relaxation time of hot electrons in laser-solid interaction at relativistic laser intensities

    SciTech Connect

    Chen, H; Shepherd, R; Chung, H K; Dyer, G; Faenov, A; Fournier, K B; Hansen, S B; Hunter, J; Kemp, A; Pikuz, T; Ping, Y; Widmann, K; Wilks, S C; Beiersdorfer, P

    2006-08-22

    The authors have measured the relaxation time of hot electrons in short pulse laser-solid interactions using a picosecond time-resolved x-ray spectrometer and a time-integrated electron spectrometer. Employing laser intensities of 10{sup 17}, 10{sup 18}, and 10{sup 19} W/cm{sup 2}, they find increased laser coupling to hot electrons as the laser intensity becomes relativistic and thermalization of hot electrons at timescales on the order of 10 ps at all laser intensities. They propose a simple model based on collisional coupling and plasma expansion to describe the rapid relaxation of hot electrons. The agreement between the resulting K{sub {alpha}} time-history from this model with the experiments is best at highest laser intensity and less satisfactory at the two lower laser intensities.

  2. Emission direction of fast electrons in laser-solid interactions at intensities from the nonrelativistic to the relativistic.

    PubMed

    Zhang, Jun; Zhang, J; Sheng, Z M; Li, Y T; Qiu, Y; Jin, Z; Teng, H

    2004-04-01

    The emission direction of outward-ejecting fast electrons generated in laser-solid interactions by 30 fs laser pulses is measured for laser intensities varying from the nonrelativistic to the relativistic. For an s-polarized incident laser beam at nonrelativistic intensities, the ejected electrons are close to the polarization direction of the laser beam. With the increase of the laser intensity, the ejected electrons are still mainly within the polarization plane, but turn away from the laser polarization direction towards the opposite direction of the incident laser beam. At relativistic intensities, electrons eject towards the direction of the reflected laser beam. The increasing ponderomotive force acceleration with the laser intensities might be responsible for the observed changes. PMID:15169107

  3. Petawatt laser absorption bounded

    PubMed Central

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-01-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials. PMID:24938656

  4. Petawatt laser absorption bounded

    NASA Astrophysics Data System (ADS)

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-06-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials.

  5. Conical crystal spectrograph for high brightness x-ray Kα spectroscopy in subpicosecond laser-solid interaction

    NASA Astrophysics Data System (ADS)

    Martinolli, E.; Koenig, M.; Boudenne, J. M.; Perelli, E.; Batani, D.; Hall, T. A.

    2004-06-01

    A high brightness crystal spectrograph was designed and successfully used to study the x-ray Kα spectrum of aluminum as a diagnostic for target heating due to suprathermal electrons in subpicosecond laser-solid interaction experiments. Conical geometry was chosen in order to enhance spatial focusing, since an extremely low signal-to-noise ratio was expected for the photon flux, and to have a reasonable spectral range while occupying only a small solid angle within the target chamber. Very high image brightness is obtained through strong spatial focusing, as well as good spectral resolution. A simple analytical model and three-dimensional numerical simulation are presented to describe the crystal characteristics. The performance of the spectrograph was tested both on an optical bench and with a ray-tracing code. The experimental spectra allowed us to estimate the target temperature and characterize the fast electron transport. The spectrograph is considered to be particularly useful, in the configuration described here, for high power laser experiments where the solid angle accessible to the spectrograph is small and blast and debris damage from the laser produced plasma is significant.

  6. Energy coupling in short pulse laser solid interactions and its impact for space debris removal.

    PubMed

    Neely, David; Allott, Ric; Bingham, Bob; Collier, John; Greenhalgh, Justin; Michaelis, Max; Phillips, Jonathan; Phipps, Claude R; McKenna, Paul

    2014-11-01

    Significant advances have been made over the last decade to improve the performance, efficiency, and contrast of high peak and average power laser systems, driven by their use in a wide variety of fields, from the industrial to the scientific. As the contrast of the lasers has improved, interactions with contrasts of 1012 are now routinely undertaken. At such high contrasts, there is negligible preplasma formation and the ionized surface layer created by subpicosecond-duration pulses typically forms a highly reflective "plasma mirror" capable of reflecting between 70% and 90% of the incident energy. Although such interactions are of significant interest for applications such as harmonic source production and to enable the underlying physics to be studied, their low absorption can limit their usefulness for applications such as space debris removal. PMID:25402936

  7. Synchrotron radiation, pair production, and longitudinal electron motion during 10-100 PW laser solid interactions

    SciTech Connect

    Brady, C. S.; Arber, T. D.; Ridgers, C. P.; York Plasma Institute, University of York, York, Yorkshire YO10 5DD ; Bell, A. R.

    2014-03-15

    At laser intensities above 10{sup 23} W/cm{sup 2}, the interaction of a laser with a plasma is qualitatively different to the interactions at lower intensities. In this intensity regime, solid targets start to become relativistically underdense, gamma-ray production by synchrotron emission starts to become an important feature of the dynamics and, at even higher intensities, electron-positron pair production by the non-linear Breit-Wheeler process starts to occur. In this paper, an analysis is presented of the effects of target density, laser intensity, target preplasma properties, and other parameters on the conversion efficiency, spectrum, and angular distribution of gamma-rays by synchrotron emission. An analysis of the importance of Breit-Wheeler pair production is also presented. Target electron densities between 10{sup 22} cm{sup −3} and 5 × 10{sup 24} cm{sup −3} and laser intensities covering the range between 10{sup 21} W/cm{sup 2} (available with current generation laser facilities) and 10{sup 24} W/cm{sup 2} (upper intensity range expected from the ELI facility are considered. Results are explained in terms of the behaviour of the head of the laser pulse as it interacts with the target.

  8. Ultrafast electron radiography of magnetic fields in high-intensity laser-solid interactions.

    PubMed

    Schumaker, W; Nakanii, N; McGuffey, C; Zulick, C; Chyvkov, V; Dollar, F; Habara, H; Kalintchenko, G; Maksimchuk, A; Tanaka, K A; Thomas, A G R; Yanovsky, V; Krushelnick, K

    2013-01-01

    Using electron bunches generated by laser wakefield acceleration as a probe, the temporal evolution of magnetic fields generated by a 4 × 10(19) W/cm(2) ultrashort (30 fs) laser pulse focused on solid density targets is studied experimentally. Magnetic field strengths of order B(0) ~ 10(4) T are observed expanding at close to the speed of light from the interaction point of a high-contrast laser pulse with a 10-μm-thick aluminum foil to a maximum diameter of ~1 mm. The field dynamics are shown to agree with particle-in-cell simulations. PMID:23383801

  9. Effects of the plasma profiles on photon and pair production in ultrahigh intensity laser solid interaction

    SciTech Connect

    Tian, Y. X.; Jin, X. L. Yan, W. Z.; Li, J. Q.; Li, B.; Yu, J. Q.

    2015-12-15

    The model of photon and pair production in strong field quantum electrodynamics is implemented into our 1D3V particle-in-cell code with Monte Carlo algorithm. Using this code, the evolution of the particles in ultrahigh intensity laser (∼10{sup 23} W/cm{sup 2}) interaction with aluminum foil target is observed. Four different initial plasma profiles are considered in the simulations. The effects of initial plasma profiles on photon and pair production, energy spectra, and energy evolution are analyzed. The results imply that one can set an optimal initial plasma profile to obtain the desired photon distributions.

  10. Experimental study on electron transport in high intensity laser solid interaction w/o cone

    NASA Astrophysics Data System (ADS)

    Baton, Sophie; Guillou, P.; Batani, D.; Rousseaux, C.; Kodama, R.; Aglitskiy, Y.

    2005-10-01

    New electron transport results have been obtained in the interaction of a high intensity laser with planar solid target w/o gold cone. The experiment has been performed at the LULI Laboratory with the 100 TW laser facility. The interaction took place either at 1.057 μm or at 0.53 μm wavelength. The targets consist of three layers planar targets molecularly bonded w/o gold cone glued on the front side. The target thickness and the surface size, the target holder, the ASE of the laser and its focalisation point have been varied in order to study their influence on the electron transport. Several diagnostics were implemented: visible rear side imaging, HISAC, X-ray-Kα imaging and spectroscopy and the angular distribution of the emitted protons. In our conditions, no significant cone effect was observed. Nevertheless these results seem to indicate that the behaviour of the fast electrons is highly influenced by the target mass.

  11. Demonstration of Coherent Terahertz Transition Radiation from Relativistic Laser-Solid Interactions.

    PubMed

    Liao, Guo-Qian; Li, Yu-Tong; Zhang, Yi-Hang; Liu, Hao; Ge, Xu-Lei; Yang, Su; Wei, Wen-Qing; Yuan, Xiao-Hui; Deng, Yan-Qing; Zhu, Bao-Jun; Zhang, Zhe; Wang, Wei-Min; Sheng, Zheng-Ming; Chen, Li-Ming; Lu, Xin; Ma, Jing-Long; Wang, Xuan; Zhang, Jie

    2016-05-20

    Coherent transition radiation in the terahertz (THz) region with energies of sub-mJ/pulse has been demonstrated by relativistic laser-driven electron beams crossing the solid-vacuum boundary. Targets including mass-limited foils and layered metal-plastic targets are used to verify the radiation mechanism and characterize the radiation properties. Observations of THz emissions as a function of target parameters agree well with the formation-zone and diffraction model of transition radiation. Particle-in-cell simulations also well reproduce the observed characteristics of THz emissions. The present THz transition radiation enables not only a potential tabletop brilliant THz source, but also a novel noninvasive diagnostic for fast electron generation and transport in laser-plasma interactions. PMID:27258873

  12. Angular emission and polarization dependence of harmonics from laser-solid interactions

    NASA Astrophysics Data System (ADS)

    Easter, J. H.; Nees, J. A.; Hou, B. X.; Mordovanakis, A.; Mourou, G.; Thomas, A. G. R.; Krushelnick, K.

    2013-02-01

    Laser plasma interaction experiments have been performed to characterize high order harmonic emission up to the 18th order using high rep rate mJ level laser pulses at relativistic intensities. The experiments were compared to two- and three-dimensional particle-in-cell simulations. The harmonic divergence was found to be less than 4° (full-width at half-maximum) at highest intensity and increased as the laser was defocused (i.e. as the intensity was reduced). The polarization dependence on the harmonic generation efficiency and divergence was also measured. Circular polarization was found to cause a deflection in the angle of emission of the harmonics—an effect which may be beneficial in the use of such harmonics for efficient isolated attosecond pulse production.

  13. Demonstration of Coherent Terahertz Transition Radiation from Relativistic Laser-Solid Interactions

    NASA Astrophysics Data System (ADS)

    Liao, Guo-Qian; Li, Yu-Tong; Zhang, Yi-Hang; Liu, Hao; Ge, Xu-Lei; Yang, Su; Wei, Wen-Qing; Yuan, Xiao-Hui; Deng, Yan-Qing; Zhu, Bao-Jun; Zhang, Zhe; Wang, Wei-Min; Sheng, Zheng-Ming; Chen, Li-Ming; Lu, Xin; Ma, Jing-Long; Wang, Xuan; Zhang, Jie

    2016-05-01

    Coherent transition radiation in the terahertz (THz) region with energies of sub-mJ/pulse has been demonstrated by relativistic laser-driven electron beams crossing the solid-vacuum boundary. Targets including mass-limited foils and layered metal-plastic targets are used to verify the radiation mechanism and characterize the radiation properties. Observations of THz emissions as a function of target parameters agree well with the formation-zone and diffraction model of transition radiation. Particle-in-cell simulations also well reproduce the observed characteristics of THz emissions. The present THz transition radiation enables not only a potential tabletop brilliant THz source, but also a novel noninvasive diagnostic for fast electron generation and transport in laser-plasma interactions.

  14. Proton beam generation by ultra-high intensity laser-solid interaction

    NASA Astrophysics Data System (ADS)

    Manclossi, M.; Guemnie-Tafo, A.; Batani, D.; Malka, V.; Fritzler, S.; Lefebvre, E.; D'Humieres, E.

    2005-10-01

    We report on some recent experimental results on proton production from ultra-intense laser pulse interaction with thin aluminium and plastic foil targets. These results were obtained at Laboratoire d'Optique Appliquee with the 100TW 'salle jaune' laser system, delivering 35 fs laser pulses at 0.8 mu m, reaching a maximum intensity on target of a few 10(19) W/cm(2). In such extreme interaction conditions, an intense and collimated relativistic electron current is injected from the plasma created on the laser focal spot into the cold interior of the target. Its transport through dense matter, ruled by both collisions and self-induced (electro-magnetic) field effects, is the driving mechanism for proton acceleration from the rear side of thin foils: when reaching and leaving the foil rear-side, the fast electrons create a large charge separation and a huge electrostatic field with a maximum value of few TV/m, capable of accelerating protons. A parametric study as a function of the laser driver and target parameters indicates an optimal value for target thickness, which strongly depends on the laser prepulse duration. In our experiments, we did irradiate targets of various materials (CH, Al, Au) changing the prepulse duration by using fast Pockels cells in the laser chain. CR-39 nuclear track detectors with Al filters of different thickness and a Thomson parabola were used to detect proton generation. The best results were obtained for 2 mu m Al targets, leading to the generation of proton energies with energies up to 12 MeV.

  15. The scaling of electron and positron generation in intense laser-solid interactions

    SciTech Connect

    Chen, Hui; Link, A.; Fiuza, F.; Hazi, A.; Heeter, R. F.; Kemp, A. J.; Kemp, G. E.; Nagel, S. R.; Park, J.; Tommasini, R.; Williams, G. J.; Sentoku, Y.; Audebert, P.; Hill, M.; Hobbs, L.; Kerr, S.; Meyerhofer, D. D.; Myatt, J.

    2015-05-15

    This paper presents experimental scalings of the electrons and positrons produced by intense laser-target interactions at relativistic laser intensities (10{sup 18}–10{sup 20} W cm{sup −2}). The data were acquired from three short-pulse laser facilities with laser energies ranging from 80 to 1500 J. We found a non-linear (≈E{sub L}{sup 2}) scaling of positron yield [Chen et al., Phys. Rev. Lett. 114, 215001 (2015)] and a linear scaling of electron yield with the laser energy. These scalings are explained by theoretical and numerical analyses. Positron acceleration by the target sheath field is confirmed by the positron energy spectrum, which has a pronounced peak at energies near the sheath potential, as determined by the observed maximum energies of accelerated protons. The parameters of laser-produced electron-positron jets are summarized together with the theoretical energy scaling. The measured energy-squared scaling of relativistic electron-positron jets indicates the possibility to create an astrophysically relevant experimental platform with such jets using multi-kilojoule high intensity lasers currently under construction.

  16. Three dimensional effects on proton acceleration by intense laser solid target interaction

    NASA Astrophysics Data System (ADS)

    Liu, Jin-Lu; Chen, Min; Zheng, Jun; Sheng, Zheng-Ming; Liu, Chuan-Sheng

    2013-06-01

    Multi-dimensional effects on ion acceleration by a normally incident linearly polarized intense laser pulse interacting with a thin solid target have been investigated numerically, where the laser has the peak intensity of 1.37×1020 W/cm2, focused spot size of 6 μm, pulse duration of 33 fs, and total pulse energy about 3 J, which are commercially available now. We have checked the effects of simulation geometries by running one, two, and three dimensional (1D, 2D, 3D) particle-in-cell simulations. 3D simulation results show that, in the case of using a relatively thick target (in the opaque regime, i.e., 2 μm) with the so-called target normal sheath field acceleration mechanism, electrons spread almost uniformly along two transverse directions. While in the case of using an ultra-thin target (in the relativistic-induced transparent regime, i.e., 100 nm) with the so-called break-out afterburner mechanism, electrons spread more quickly along the direction orthogonal to the laser polarization direction especially at the early stage. The transverse spreading of electrons strongly decreases the electron density at the rear side of the target. Such an effect causes different estimation of electron temperatures in different simulation geometries. Usually, 1D and 2D simulations overestimate the temperature; and as a result, the maximum proton energy observed in 1D and 2D simulations is, respectively, about 3 and 2 times of that observed in 3D simulation.

  17. Fast particle generation and energy transport in laser-solid interactions

    NASA Astrophysics Data System (ADS)

    Zepf, Matthew

    2000-10-01

    The generation and propagation of fast electrons is a topic of intense research not least due to its relevance to the Fast Ignitor Scheme [1, 2, 3]. More recently a lot of attention has also focused on the production of highly energetic protons [3,4, 5] which are observed at the rear of the target. Apart from a possible role in a modified Fast Ignitor scenario these are also of interest for generating radioactive isotopes via nuclear reactions and as a probe. We present results from a recent experimental campaign using the Vulcan (70 TW) laser at the Rutherford Appleton Laboratory. Using innovative nuclear activation techniques and CR-39 track detectors, the angular and energy distribution of the protons for a range of different targets and intensities has been measured. Various electron acceleration mechanisms are known, both in the underdense region and at the critical density surface. It is vital to understand their interplay in these complex interactions. The subsequent propagation of the electron beams through the overdense plasma is also of great importance. Since the currents generated far exceed the Alfven limit, the fast electron current needs to be almost perfectly compensated. The transport and energy deposition is therefore expected to be dominated by collective effects rather than the single electron scattering stopping range. We will show recent results showing the dependence of electron beam directionality, generation mechanism and energy deposition on a range of laser parameters. [1] M. Tabak et al., Phys. Plasmas 1, pp.1626 (1994) [2] M. Santala et al., Phys. Rev. Lett 84, pp. 1459 (2000) [3] Hatchett et al., Phys. Plasmas 7, pp. 2076 (2000) [4] E. Clark et al., Phys. Rev. Lett., 84, pp. 670 (2000) [5] A. Maksimchuk et al. Phys, Rev. Lett 84, pp. 4108 (2000)

  18. Three dimensional effects on proton acceleration by intense laser solid target interaction

    SciTech Connect

    Liu, Jin-Lu; Zheng, Jun; Chen, Min; Sheng, Zheng-Ming; Department of Mathematics, Institute of Natural Sciences, and MOE-LSC, Shanghai Jiao Tong University, Shanghai 200240 ; Liu, Chuan-Sheng

    2013-06-15

    Multi-dimensional effects on ion acceleration by a normally incident linearly polarized intense laser pulse interacting with a thin solid target have been investigated numerically, where the laser has the peak intensity of 1.37×10{sup 20} W/cm{sup 2}, focused spot size of 6 μm, pulse duration of 33 fs, and total pulse energy about 3 J, which are commercially available now. We have checked the effects of simulation geometries by running one, two, and three dimensional (1D, 2D, 3D) particle-in-cell simulations. 3D simulation results show that, in the case of using a relatively thick target (in the opaque regime, i.e., 2 μm) with the so-called target normal sheath field acceleration mechanism, electrons spread almost uniformly along two transverse directions. While in the case of using an ultra-thin target (in the relativistic-induced transparent regime, i.e., 100 nm) with the so-called break-out afterburner mechanism, electrons spread more quickly along the direction orthogonal to the laser polarization direction especially at the early stage. The transverse spreading of electrons strongly decreases the electron density at the rear side of the target. Such an effect causes different estimation of electron temperatures in different simulation geometries. Usually, 1D and 2D simulations overestimate the temperature; and as a result, the maximum proton energy observed in 1D and 2D simulations is, respectively, about 3 and 2 times of that observed in 3D simulation.

  19. Petawatt laser absorption bounded

    NASA Astrophysics Data System (ADS)

    Levy, Matthew; Wilks, Scott; Tabak, Max; Libby, Stephen; Baring, Matthew

    2014-10-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top relativistic particle accelerators, ultrafast charged particle imaging systems and fast ignition inertial confinement fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. In this presentation, using a relativistic Rankine-Hugoniot-like analysis, we show how to derive the theoretical maximum and minimum of f. These boundaries constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. Close agreement is shown with several dozens of published experimental data points and simulation results, helping to confirm the theory. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials.

  20. Controlled electron bunch generation in the few-cycle ultra-intense laser-solid interaction scenario

    NASA Astrophysics Data System (ADS)

    Kluge, T.; Bussmann, M.; Cowan, T. E.; Schramm, U.

    2016-09-01

    The generation of Maxwellian or exponentially decaying spectra in the interaction of ultra-intense ultra-short laser pulses with solid foils is very general observation both in experiments and simulations. Yet, the physical origin of this observation is not well understood. For a very idealized situation of plane wave, plane and cold target interaction, we show that both randomization between individual electron bunches accelerated by the laser through the plasma as well as randomization during a single bunch are not observable in particle-in-cell simulations. Hence they are not accountable for the apparent thermalization (exponential spectrum).

  1. High performance compact magnetic spectrometers for energetic ion and electron measurement in ultra intense short pulse laser solid interactions

    SciTech Connect

    Chen, H; Link, A; van Maren, R; Patel, P; Shepherd, R; Wilks, S C; Beiersdorfer, P

    2008-05-08

    Ultra intense short pulse lasers incident on solid targets can generate relativistic electrons that then accelerate energetic protons and ions. These fast electrons and ions can effectively heat the solid target, beyond the region of direct laser interaction, and are vital to realizing the fast ignition concept. To study these energetic ions and electrons produced from the laser-target interactions, we have developed a range of spectrometers that can cover a large energy range (from less than 0.1 MeV to above 100 MeV). They are physically compact and feature high performance and low cost. We will present the basic design of these spectrometers and their test results from recent laser experiments.

  2. Deflection of MeV electrons by self-generated magnetic fields in intense laser-solid interactions.

    PubMed

    Pérez, F; Kemp, A J; Divol, L; Chen, C D; Patel, P K

    2013-12-13

    We show that the interaction of relativistic-intensity, picosecond laser pulses with solid targets is affected by the reflected light through the strong currents and 10(4)  T magnetic fields it produces. Three-dimensional particle-in-cell simulations, with the axisymmetry broken by a small angle of incidence, show that these magnetic fields deflect the laser-accelerated electrons away from the incident laser axis. This directly impacts the interpretation of electron divergence and directionality in applications such as laser-driven ion acceleration or fast-ignition inertial fusion. PMID:24483668

  3. High-resolution multi-MeV x-ray radiography using relativistic laser-solid interaction

    SciTech Connect

    Courtois, C.; Compant La Fontaine, A.; Barbotin, M.; Bazzoli, S.; Brebion, D.; Bourgade, J. L.; Gazave, J.; Lagrange, J. M.; Landoas, O.; Le Dain, L.; Lefebvre, E.; Pichoff, N.; Edwards, R.; Aedy, C.; Biddle, L.; Drew, D.; Gardner, M.; Ramsay, M.; Simons, A.; Sircombe, N.

    2011-02-15

    When high intensity ({>=}10{sup 19} W cm{sup -2}) laser light interacts with matter, multi-MeV electrons are produced. These electrons can be utilized to generate a MeV bremsstrahlung x-ray emission spectrum as they propagate into a high-Z solid target positioned behind the interaction area. The short duration (<10 ps) and the small diameter (<500 {mu}m) of the x-ray pulse combined with the MeV x-ray spectrum offers an interesting alternative to conventional bremsstrahlung x-ray sources based on an electron accelerator used to radiograph dense, rapidly moving objects. In experiments at the Omega EP laser, a multi-MeV x-ray source is characterized consistently with number of independent diagnostics. An unfiltered x-ray dose of approximately 2 rad in air at 1 m and a source diameter of less than 350 {mu}m are inferred. Radiography of a complex and high area density (up to 61 g/cm{sup 2}) object is then performed with few hundred microns spatial resolution.

  4. Intense high repetition rate Mo Kα x-ray source generated from laser solid interaction for imaging application

    SciTech Connect

    Huang, K.; Li, M. H.; Yan, W. C.; Ma, Y.; Zhao, J. R.; Li, Y. F.; Chen, L. M.; Guo, X.; Li, D. Z.; Chen, Y. P.; Zhang, J.

    2014-11-15

    We report an efficient Mo Kα x-ray source produced by interaction of femtosecond Ti: sapphire laser pulses with a solid Molybdenum target working at 1 kHz repetition rate. The generated Mo Kα x-ray intensity reaches to 4.7 × 10{sup 10} photons sr{sup −1} s{sup −1}, corresponding to an average power of 0.8 mW into 2π solid angle. The spatial resolution of this x-ray source is measured to be 26 lp/mm. With the high flux and high spatial resolution characteristics, high resolving in-line x-ray radiography was realized on test objects and large size biological samples within merely half a minute. This experiment shows the possibility of laser plasma hard x-ray source as a new low cost and high resolution system for radiography and its ability of ultrafast x-ray pump-probe study of matter.

  5. Narrow Energy Spread Protons and Ions from High-Intensity, High-Contrast Laser Solid Target Interactions

    SciTech Connect

    Dollar, Franklin; Matsuoka, Takeshi; McGuffey, Christopher; Bulanov, Stepan S.; Chvykov, Vladimir; Kalintchenko, Galina; Thomas, Alec G. R.; Willingale, Louise; Yanovsky, Victor; Maksimchuk, Anatoly; Krushelnick, Karl; Davis, Jack; Petrov, George

    2010-11-04

    Recent simulations show that an idealized, high intensity, short pulse laser can generate quasi-monoenergetic proton beams with energies over 100 MeV in an interaction with a thin film. However, most short pulse laser facilities with sufficient intensity have difficulty controlling the nanosecond and picosecond contrast necessary to realize such a regime. Experiments were performed to investigate proton and ion acceleration from a high contrast, short pulse laser by employing dual plasma mirrors along with a deformable mirror at the HERCULES laser facility at the Center for Ultrafast Optical Sciences, University of Michigan. Plasma mirrors were characterized, allowing a 50% throughput with an intensity contrast increase of 105. The focal spot quality was also exceptional, showing a 1.1 micron full width at half maximum (FWHM) focal diameter. Experiments were done using temporally cleaned 30 TW, 32 fs pulses to achieve an intensity of up to 10{sup 21} Wcm{sup -2} on Si{sub 3}N{sub 4} and Mylar targets with thicknesses ranging 50 nm to 13 microns. Proton beams with energy spreads below 2 MeV were observed from all thicknesses, peaking with energies up to 10.3 MeV and an energy spread of 0.8 MeV. Similar narrow energy spreads were observed for oxygen, nitrogen, and carbon at the silicon nitride thickness of 50 nm with energies up to 24 MeV with an energy spread of 3 MeV, whereas the energy spread is greatly increased at a larger thickness. Maximum energies were confirmed with CR39 track detectors, while a Thomson ion spectrometer was used to gauge the monoenergetic nature of the beam.

  6. Simulations of the interaction of intense petawatt laser pulses with dense Z-pinch plasmas : final report LDRD 39670.

    SciTech Connect

    Welch, Dale Robert; MacFarlane, Joseph John; Mehlhorn, Thomas Alan; Campbell, Robert B.

    2004-11-01

    We have studied the feasibility of using the 3D fully electromagnetic implicit hybrid particle code LSP (Large Scale Plasma) to study laser plasma interactions with dense, compressed plasmas like those created with Z, and which might be created with the planned ZR. We have determined that with the proper additional physics and numerical algorithms developed during the LDRD period, LSP was transformed into a unique platform for studying such interactions. Its uniqueness stems from its ability to consider realistic compressed densities and low initial target temperatures (if required), an ability that conventional PIC codes do not possess. Through several test cases, validations, and applications to next generation machines described in this report, we have established the suitability of the code to look at fast ignition issues for ZR, as well as other high-density laser plasma interaction problems relevant to the HEDP program at Sandia (e.g. backlighting).

  7. Generation of Nonlinear Force Driven Blocks from Skin Layer Interaction of Petawatt-Picosecond Laser Pulses for ICF

    NASA Astrophysics Data System (ADS)

    Heinrich, Hora; Cang, Yu; He, Xiantu; Zhang, Jie; F, Osman; J, Badziak; F, P. Boody; S, Gammino; R, Höpfl; K, Jungwirth; B, Kralikova; J, Kraska; L, Laska; Liu, Hong; G, H. Miley; P, Parys; Peng, Hansheng; M, Pfeifer; K, Rohlena; J, Skala; Z, Skladanowski; L, Torrisi; J, Ullschmied; J, Wolowski; Zhang, Weiyan

    2004-02-01

    The discovery of the essential difference of maximum ion energy for TW - ps laser plasma interaction compared with the 100 ns laser pulses [1] led to the theory of a skin layer model [2] where the control of prepulses suppressed the usual relativistic self-focusing. The subsequent generation of two nonlinear force driven blocks has been demonstrated experimentally and in extensive numerical studies where one block moves against the laser light and the other block into the irradiated target. These blocks of nearly solid state density DT plasma correspond to ion beam current densities [3] exceeding 1010 A/cm2 where the ion velocity can be chosen up to highly relativistic values. Using the results of the expected ignition of DT fuel by light ion beams, a self-sustained fusion reaction front may be generated even into uncompressed solid DT fuel similar to the Nuckolls-Wood [4] scheme where 10 kJ laser pulses produce 100 MJ fusion energy. This new and simplified scheme of laser-ICF needs and optimisation of the involved parameters.

  8. Laser Wakefield Acceleration in the PetaWatt Regime

    NASA Astrophysics Data System (ADS)

    Joshi, C.; Tsung, F. S.; Mori, W. B.; Katsouleas, T.; Fonseca, R. A.; Silva, L. O.

    2003-10-01

    Laser wakefield acceleration with multi-terawatt lasers has demonstrated impressive results in experiments around the world-- e.g., energy gains up to 700 MeV in mm-scale gas jets has recently been reported. With a number of petawatt class lasers planned for operation in the near future, we examine with 2-D and 3-D PIC simulations the potential energy gain and new physics of laser wakefield acceleration in this regime. These lasers will operated for a variety of pulse lengths. We consider both 35 fs and 600 fs pulses, but will emphasize the 35 fs results for this poster. Prospects for producing GeV electron beams in underdense plasmas will be described. In addition, the differences in physics between terawatt and petawatt regimes will be explored. Preliminary results for the 35 fs class lasers indicate that there are two acceleration stages in the petawatt regime -- with the early electrons dephasing due to elongation of the laser wake as the laser pump evolves. The later stage produces a long beam of electrons several times the initial plasma wake wavelength with a fairly defined energy in the GeV range. For the 600 fs class lasers, 2D simulations indicate that the acceleration process is much more complicated and it involves an interaction between the fields in the wake and the laser.

  9. Quasimonoenergetic Electron Beams with Relativistic Energies and Ultrashort Duration from Laser-Solid Interactions at 0.5 kHz

    SciTech Connect

    Mordovanakis, Aghapi G.; Easter, James; Hou Bixue; Nees, John; Krushelnick, Karl; Naumova, Natalia; Popov, Konstantin; Rozmus, Wojciech; Masson-Laborde, Paul-Edouard; Sokolov, Igor; Mourou, Gerard; Glazyrin, Igor V.; Bychenkov, Valery

    2009-12-04

    We investigate the production of electron beams from the interaction of relativistically-intense laser pulses with a solid-density SiO{sub 2} target in a regime where the laser pulse energy is approxmJ and the repetition rate approxkHz. The electron beam spatial distribution and spectrum were investigated as a function of the plasma scale length, which was varied by deliberately introducing a moderate-intensity prepulse. At the optimum scale length of lambda/2, the electrons are emitted in a collimated beam having a quasimonoenergetic distribution that peaked at approx0.8 MeV. A highly reproducible structure in the spatial distribution exhibits an evacuation of electrons along the laser specular direction and suggests that the electron beam duration is comparable to that of the laser pulse. Particle-in-cell simulations which are in good agreement with the experimental results offer insights on the acceleration mechanism by the laser field.

  10. Fast-electron source characterization and transport in high-intensity laser-solid interactions and the role of resistive magnetic fields

    NASA Astrophysics Data System (ADS)

    Storm, Michael

    An electron transport regime is identified in which >1 MA, relativistic currents, generated by high-intensity, laser-target interactions, are collimated (or focused) by self-generated, resistive, magnetic fields within solid-density targets. The strongest magnetic fields appear at the edge of the electric current due to the radial shear in the current density. High-resolution coherent transition radiation (CTR) imaging of the target rear surface diagnoses the electrons that are accelerated from the target front surface by a laser that is focused to an intensity of I ˜ 10 19 Wcm-2. CTR is emitted when an electron beam, with longitudinal electron density modulations, crosses a refractive index interface such as the target rear surface. A fast electron temperature of T hot = 1.4 +/- 0.1 MeV is inferred from variations in the radiated CTR energy with target thickness. Variation in the CTR emitted energy with laser intensity obeys the power law ECTR ∝ I5.7 +/- 0.5. These results are consistent with the predictions of the ponderomotive scaling law. The high resolution images show the presence of bright, micron-scale structures in the CTR emission that indicate that the electron beam filaments. The micron scale structures are superimposed onto larger annular structures that suggest the electron beam hollows as it propagates. The variation in the spatial extent of the CTR emission with increasing target thickness gives an electron beam angular divergence of theta1/2 = 15.7 +/- 0.9°. Three-dimensional, hybrid-particle-in-cell code simulations of the electron transport indicate a target rear-surface electron density distribution that reproduces the details of the CTR emission seen in the experiments. The variation of the electron density distribution with increasing target thickness resembles an expanding annulus that breaks into filaments due to the resistive filamentation instability. The radially expanding annular pattern results from the partial collimation of an

  11. Ultraintense laser-solid interaction phenomena

    SciTech Connect

    Mulser, P.; Bauer, D.; Hain, S.; Cornolti, F.

    1998-02-20

    In the variety of processes occurring in matter under the action of superstrong laser fields rapid field ionization and ponderomotive effects play a dominant role. We investigate field ionization by solving the time-dependent Schroedinger equation numerically and compare the results with classical calculations. We obtain the ionization rates of hydrogen-like ions, the ejection energy spectrum of the electrons, and we show the transition to classical behavior at high energies. In addition, we are able to give a physical explanation of non-sequential ionization. Our ionization rates differ by more than an order of magnitude from the standard expressions. A model is presented which allows to calculate the back action of field ionization on the laser beam. Finally, we present the most general relativistic derivation of ponderomotive forces on single particles and present their transformation properties. Ponderomotive forces are of non-Newtonian character.

  12. Engineering the Petawatt Laser into Nova

    SciTech Connect

    Tietbohl, G.L.; Bell, P.M.; Hamilton, R.M.

    1997-12-23

    The engineering process of integrating the Petawatt (10{sup 15} watts) laser system into the existing 30 kJ (UV) Nova laser at Lawrence Livermore National Laboratory (LLNL) is described in detail. The nanosecond-long, chirped Petawatt laser pulse is initially generated in a separate master oscillator room and then injected into one of Nova`s 10 beamlines. There, the pulse is further amplified and enlarged to {approximately}{phi}60 cm, temporally compressed under vacuum to <500 fs using large diameter diffraction gratings, and then finally focused onto targets using a parabolic mirror. The major Petawatt components are physically large which created many significant engineering challenges in design, installation and implementation. These include the diffraction gratings and mirrors, vacuum compressor chamber, target chamber, and parabolic focusing mirror. Other Petawatt system components were also technically challenging and include: an injection beamline, transport spatial filters, laser diagnostics, alignment components, motor controls, interlocks, timing and synchronization systems, support structures, and vacuum systems. The entire Petawatt laser system was designed, fabricated, installed, and activated while the Nova laser continued its normal two-shift operation. This process required careful engineering and detailed planning to prevent experimental downtime and to complete the project on schedule.

  13. Petawatt pulsed-power accelerator

    DOEpatents

    Stygar, William A.; Cuneo, Michael E.; Headley, Daniel I.; Ives, Harry C.; Ives, legal representative; Berry Cottrell; Leeper, Ramon J.; Mazarakis, Michael G.; Olson, Craig L.; Porter, John L.; Wagoner; Tim C.

    2010-03-16

    A petawatt pulsed-power accelerator can be driven by various types of electrical-pulse generators, including conventional Marx generators and linear-transformer drivers. The pulsed-power accelerator can be configured to drive an electrical load from one- or two-sides. Various types of loads can be driven; for example, the accelerator can be used to drive a high-current z-pinch load. When driven by slow-pulse generators (e.g., conventional Marx generators), the accelerator comprises an oil section comprising at least one pulse-generator level having a plurality of pulse generators; a water section comprising a pulse-forming circuit for each pulse generator and a level of monolithic triplate radial-transmission-line impedance transformers, that have variable impedance profiles, for each pulse-generator level; and a vacuum section comprising triplate magnetically insulated transmission lines that feed an electrical load. When driven by LTD generators or other fast-pulse generators, the need for the pulse-forming circuits in the water section can be eliminated.

  14. Nuclear diagnostics for petawatt experiments (invited)

    SciTech Connect

    Stoyer, M. A.; Sangster, T. C.; Henry, E. A.; Cable, M. D.; Cowan, T. E.; Hatchett, S. P.; Key, M.H.; Moran, M. J.; Pennington, D. M.; Perry, M. D.

    2001-01-01

    With the operation of successively more intense and powerful lasers, such as the NOVA petawatt laser with I{approx}3x10{sup 20} W/cm{sup 2}, several novel (to laser physics) nuclear diagnostics were used to determine the nature of the laser/matter interaction at the target surface. A broad beam of hot electrons, whose centroid varied from shot to shot, width was remarkably constant, and intensity was about 40% of the incident laser energy was observed. New nuclear phenomenon included photonuclear reactions [e.g., ({gamma},xn)], photofission of {sup 238}U and intense beams of ions. Photonuclear reactions were observed and quantified in Cu, Ni, and Au samples, and produced activation products as neutron deficient as {sup 191}Au [a ({gamma},6n) reaction!], requiring gamma rays exceeding 50 MeV in energy. The spectral features of the gamma-ray source have been investigated by comparing activation ratios in Ni and Au samples, and angular distributions of higher energy photons have been measured with activation of spatially distributed Au samples. Extraordinarily intense beams of charged particles (primarily protons) were observed normal to the rear surface of the target and quantified using the charged particle reaction {sup 48}Ti(p,n){sup 48}V, radiochromic film and CR39 plastic track detectors. Approximately 3x10{sup 13} protons, with energies up to 55 MeV were observed in some experiments. Collimation of this beam increases with increasing proton energy. Correlations of activation with laser performance will be discussed.

  15. Progress in fast ignitor research with the Nova petawatt laser

    NASA Astrophysics Data System (ADS)

    Key, Michael H.

    1997-11-01

    The concept of isochoric fast ignition developed at LLNL by Tabak et at [1] is of importance through its potential to give higher gain than isobaric central spark ignition and thereby to relax the driver efficiency required for inertial fusion energy . The physics of fast ignition is new and challenging involving strongly relativistic laser plasma interactions and transport of energy by MeV electrons where self generated magnetic fields may strongly modify the transport . A petawatt laser beam line developed by Perry et al [ 2] at the Nova facility has recently come into operation and is being deployed in a goal oriented program to evaluate fast ignition . This laser is an order of magnitude more energetic than comparable facilities elsewhere. Theory and modeling work with PIC and fluid codes is being used to guide and interpret the experiments [1] which are emphasizing characterization of the hot electron source from Ka fluorescence of buried layers and the heating produced at depth by hot electrons from X-ray spectroscopy and fusion yield of buried layers . A related study concerns the penetration of laser radiation by hole boring in supercritical density targets . [1] M Tabak J Hammer M E Glinsky W L Kruer S C Wilks J Woodworth E M Campbell M D Perry . Ignition and high gain with Ultra powerful lasers . Phys Plasmas, 1, 1626, (1994) [2] M. D. Perry, "Crossing the Petawatt Threshold" Science & Technology Review page 4, December 1996.

  16. Gratings for High-Energy Petawatt Lasers

    SciTech Connect

    Nguyen, H T; Britten, J A; Carlson, T C; Nissen, J D; Summers, L J; Hoaglan, C R; Aasen, M D; Peterson, J E; Jovanovic, I

    2005-11-08

    To enable high-energy petawatt laser operation we have developed the processing methods and tooling that produced both the world's largest multilayer dielectric reflection grating and the world's highest laser damage resistant gratings. We have successfully delivered the first ever 80 cm aperture multilayer dielectric grating to LLNL's Titan Intense Short Pulse Laser Facility. We report on the design, fabrication and characterization of multilayer dielectric diffraction gratings.

  17. The Texas petawatt laser and current experiments

    SciTech Connect

    Martinez, Mikael; Bang, Woosuk; Dyer, Gilliss; Wang Xiaoming; Gaul, Erhard; Borger, Teddy; Ringuette, Martin; Spinks, Michael; Quevedo, Hernan; Bernstein, Aaron; Donovan, Michael; Ditmire, Todd

    2012-12-21

    The Texas Petawatt Laser is operational with experimental campaigns executed in both F/40 and F3 target chambers. Recent improvements have resulted in intensities of >2 Multiplication-Sign 10{sup 21} W/cm{sup 2} on target. Experimental highlights include, accelerated electron energies of >2 GeV, DD fusion ion temperatures >25 keV and isochorically heated solids to 10-50 eV.

  18. Plasma lenses for ultrashort multi-petawatt laser pulses

    SciTech Connect

    Palastro, J. P.; Gordon, D.; Hafizi, B.; Johnson, L. A.; Peñano, J.; Hubbard, R. F.; Helle, M.; Kaganovich, D.

    2015-12-15

    An ideal plasma lens can provide the focusing power of a small f-number, solid-state focusing optic at a fraction of the diameter. An ideal plasma lens, however, relies on a steady-state, linear laser pulse-plasma interaction. Ultrashort multi-petawatt (MPW) pulses possess broad bandwidths and extreme intensities, and, as a result, their interaction with the plasma lens is neither steady state nor linear. Here, we examine nonlinear and time-dependent modifications to plasma lens focusing, and show that these result in chromatic and phase aberrations and amplitude distortion. We find that a plasma lens can provide enhanced focusing for 30 fs pulses with peak power up to ∼1 PW. The performance degrades through the MPW regime, until finally a focusing penalty is incurred at ∼10 PW.

  19. Plasma lenses for ultrashort multi-petawatt laser pulses

    NASA Astrophysics Data System (ADS)

    Palastro, J. P.; Gordon, D.; Hafizi, B.; Johnson, L. A.; Peñano, J.; Hubbard, R. F.; Helle, M.; Kaganovich, D.

    2015-12-01

    An ideal plasma lens can provide the focusing power of a small f-number, solid-state focusing optic at a fraction of the diameter. An ideal plasma lens, however, relies on a steady-state, linear laser pulse-plasma interaction. Ultrashort multi-petawatt (MPW) pulses possess broad bandwidths and extreme intensities, and, as a result, their interaction with the plasma lens is neither steady state nor linear. Here, we examine nonlinear and time-dependent modifications to plasma lens focusing, and show that these result in chromatic and phase aberrations and amplitude distortion. We find that a plasma lens can provide enhanced focusing for 30 fs pulses with peak power up to ˜1 PW. The performance degrades through the MPW regime, until finally a focusing penalty is incurred at ˜10 PW.

  20. Multi-GeV electron acceleration driven by the Texas Petawatt laser

    NASA Astrophysics Data System (ADS)

    Wang, X.; Du, D.; Yi, S. A.; D'Avignon, E.; Kalmykov, S.; Reed, S.; Henderson, W.; Dong, P.; Zgadzaj, R.; Dyer, G.; Gaul, E.; Martinez, M.; Ditmire, T.; Shvets, G.; Downer, M.

    2010-03-01

    We present the preparation for high energy (multi-GeV) electron generation in underdense plasmas interacting with 1PW, 150fs Texas Petawatt laser pulses. Electron laser wakefield acceleration experiments have demonstrated that 1GeV electron beams can be produced with multi-TW class laser systems. Scaling laws and simulations have predicted that 3-10GeV electrons can be generated with a short pulse PW laser system without any external guiding mechanism. The Texas Petawatt system has an F /40 focusing geometry, which along with laser self-guiding creates a long laser plasma interaction length while still maintaining intensity above 10^19W/cm^2. This configuration also creates an opportunity to ``visualize'' the plasma wakefield structures using the single shot frequency-domain holography (FDH) technique. This presentation includes the Texas Petawatt laser, laser wakefield experimental setup, plasma diagnostic setup and anticipated preliminary experimental results during 2010. Particle-in-cell (PIC) simulations of laser wakefield electron acceleration and the FDH diagnostic are also presented.

  1. Laser Wakefield Acceleration in the PetaWatt Regime

    NASA Astrophysics Data System (ADS)

    Katsouleas, Tom; Tsung, Frank; Mori, Warren

    2002-11-01

    Laser wakefield acceleration with multi-terawatt lasers has demonstrated impressive results in experiments around the world-- e.g., energy gains up to 200 MeV in mm-scale gas jets. With the prospects good for a number of petawatt class lasers in the near future, we examine with 2-D and 3-D PIC simulations the potential energy gain and new physics of laser wakefield acceleration in this regime. Prospects for producing GeV electron beams in underdense plasmas will be described. In addition, the differences in physics between terawatt and petawatt regimes will be explored. Preliminary results indicate that there are two acceleration stages in the petawatt regime -- with the early electrons dephasing due to elongation of the laser wake as the laser pump evolves. The later stage produces a long beam of electrons several times the initial plasma wake wavelength with a fairly defined energy in the GeV range.

  2. High-Energy Petawatt Capability for the Omega Laser

    SciTech Connect

    Waxer, L.J.; Maywar, D.N.; Kelly, J.H.; Kessler, T.J.; Kruschwitz, B.E.; Loucks, S.J.; McCrory, R.L.; Meyerhofer, D.D.; Morse, S.F.B.; Stoeckl, C.; Zuegel, J.D.

    2005-07-25

    The 60-beam Omega laser system at the University of Rochester's Laboratory for Laser Energetics (LLE) has been a workhorse on the frontier of laser fusion and high-energy-density physics for more than a decade. LLE scientists are currently extending the performance of this unique, direct-drive laser system by adding high-energy petawatt capabilities.

  3. Hot electrons transverse refluxing in ultraintense laser-solid interactions.

    PubMed

    Buffechoux, S; Psikal, J; Nakatsutsumi, M; Romagnani, L; Andreev, A; Zeil, K; Amin, M; Antici, P; Burris-Mog, T; Compant-La-Fontaine, A; d'Humières, E; Fourmaux, S; Gaillard, S; Gobet, F; Hannachi, F; Kraft, S; Mancic, A; Plaisir, C; Sarri, G; Tarisien, M; Toncian, T; Schramm, U; Tampo, M; Audebert, P; Willi, O; Cowan, T E; Pépin, H; Tikhonchuk, V; Borghesi, M; Fuchs, J

    2010-07-01

    We have analyzed the coupling of ultraintense lasers (at ∼2×10{19}  W/cm{2}) with solid foils of limited transverse extent (∼10  s of μm) by monitoring the electrons and ions emitted from the target. We observe that reducing the target surface area allows electrons at the target surface to be reflected from the target edges during or shortly after the laser pulse. This transverse refluxing can maintain a hotter, denser and more homogeneous electron sheath around the target for a longer time. Consequently, when transverse refluxing takes places within the acceleration time of associated ions, we observe increased maximum proton energies (up to threefold), increased laser-to-ion conversion efficiency (up to a factor 30), and reduced divergence which bodes well for a number of applications. PMID:20867457

  4. High density collimated beams of relativistic ions produced by petawatt laser pulses in plasmas

    PubMed

    Sentoku; Liseikina; Esirkepov; Califano; Naumova; Ueshima; Vshivkov; Kato; Mima; Nishihara; Pegoraro; Bulanov

    2000-11-01

    Under optimal interaction conditions ions can be accelerated up to relativistic energies by a petawatt laser pulse in both underdense and overdense plasmas. Two-dimensional particle in cell simulations show that the laser pulse drills a channel through an underdense plasma slab due to relativistic self-focusing. Both ions and electrons are accelerated in the head region of the channel. However, ion acceleration is more effective at the end of the slab. Here electrons from the channel expand in vacuum and are followed by the ions dragged by the Coulomb force arising from charge separation. A similar mechanism of ion acceleration occurs when a superintense laser pulse interacts with a thin slab of overdense plasma and the pulse ponderomotive pressure moves all the electrons away from a finite-diameter spot. PMID:11102086

  5. Shielding activation of petawatt laser facilities in Romania: a FLUKA preliminary evaluation.

    PubMed

    Florescu, Gabriela M; Duliu, O G

    2016-03-01

    The FLUKA 2011.2c code was used to evaluate the activity induced in the irradiation chamber walls by secondary charged particles emitted during the interaction of 1 petawatt laser beam with the targets. The results have shown that, even in the most conservative approaches, i.e. 300 and 100 MeV secondary electrons and protons, respectively, the maximum equivalent dose rate, at 1 cm in front of the chamber wall, 1 min after the end of irradiation, was of ∼23 nSv h(-1). Three minutes later, it falls at ∼60 pSv h(-1), negligible with respect to the environmental radiation background of 90-110 nSv h(-1), as reported for Romania. PMID:26224739

  6. The Potential of Fast Ignition and Related Experiments with A Petawatt Laser Facility

    SciTech Connect

    Key, M.H.; Campbell, E.M.; Cowan, T.E.; Hatchett, S.P.; Henry, E.A.; Koch, J.A.; Langdon, A.B.; Lasinski, B.F.; MacKinnon, A.; Offenberger, A.A.; Pennington, D.M.; Perry, M. D.; Phillips, T.J.; Sangster, T.C.; Singh, M.S.; Snavely, R.A.; Stoyer, M.A.; Tsukamoto, M.; Wharton, K.B.; Wilks, S.C.

    2000-04-06

    A model of energy gain induced by fast ignition of thermonuclear burn in compressed deuterium-tritium fuel, is used to show the potential for 300x gain with a driver energy of 1 M J, if the National Ignition Facility (NIF) were to be adapted for fast ignition. The physics of fast ignition has been studied using a petawatt laser facility at the Lawrence Livermore National Laboratory. Laser plasma interaction in a preformed plasma on a solid target leads to relativistic self-focusing evidenced by x-ray images. Absorption of the laser radiation transfers energy to an intense source of relativistic electrons. Good conversion efficiency into a wide angular distribution is reported. Heating by the electrons in solid density CD{sub 2} produces 0.5 to 1/keV temperature, inferred from the D-D thermo-nuclear neutron yield.

  7. Progress on converting a NIF quad to eight, petawatt beams for advanced radiography

    NASA Astrophysics Data System (ADS)

    Crane, J. K.; Tietbohl, G.; Arnold, P.; Bliss, E. S.; Boley, C.; Britten, G.; Brunton, G.; Clark, W.; Dawson, J. W.; Fochs, S.; Hackel, R.; Haefner, C.; Halpin, J.; Heebner, J.; Henesian, M.; Hermann, M.; Hernandez, J.; Kanz, V.; McHale, B.; McLeod, J. B.; Nguyen, H.; Phan, H.; Rushford, M.; Shaw, B.; Shverdin, M.; Sigurdsson, R.; Speck, R.; Stolz, C.; Trummer, D.; Wolfe, J.; Wong, J. N.; Siders, G. C.; Barty, C. P. J.

    2010-08-01

    We are converting a quad of NIF beamlines into eight, short-pulse (1-50 ps), petawatt-class beams for advanced radiography and fast ignition experiments. This paper describes progress toward completing this project.

  8. Progress on Converting a NIF Quad to Eight, Petawatt Beams for Advanced Radiography

    SciTech Connect

    Crane, J K

    2009-10-19

    We are converting a quad of NIF beamlines into eight, short-pulse (1-50 ps), petawatt-class beams for advanced radiography and fast ignition experiments. This paper describes progress toward completing this project.

  9. Selective deuterium ion acceleration using the Vulcan petawatt laser

    NASA Astrophysics Data System (ADS)

    Krygier, A. G.; Morrison, J. T.; Kar, S.; Ahmed, H.; Alejo, A.; Clarke, R.; Fuchs, J.; Green, A.; Jung, D.; Kleinschmidt, A.; Najmudin, Z.; Nakamura, H.; Norreys, P.; Notley, M.; Oliver, M.; Roth, M.; Vassura, L.; Zepf, M.; Borghesi, M.; Freeman, R. R.

    2015-05-01

    We report on the successful demonstration of selective acceleration of deuterium ions by target-normal sheath acceleration (TNSA) with a high-energy petawatt laser. TNSA typically produces a multi-species ion beam that originates from the intrinsic hydrocarbon and water vapor contaminants on the target surface. Using the method first developed by Morrison et al. [Phys. Plasmas 19, 030707 (2012)], an ion beam with >99% deuterium ions and peak energy 14 MeV/nucleon is produced with a 200 J, 700 fs, > 10 20 W / cm 2 laser pulse by cryogenically freezing heavy water (D2O) vapor onto the rear surface of the target prior to the shot. Within the range of our detectors (0°-8.5°), we find laser-to-deuterium-ion energy conversion efficiency of 4.3% above 0.7 MeV/nucleon while a conservative estimate of the total beam gives a conversion efficiency of 9.4%.

  10. Development of a sub-petawatt ultrashort laser facility

    NASA Astrophysics Data System (ADS)

    Wang, Xiaodong; Zhu, Qihua; Su, Jingqin; Xie, Na; Jiang, Dongbin; Zhou, Kainan; Huang, Xiaojun; Zeng, Xiaoming; Guo, Yi; Sun, Li; Li, Qing

    2014-11-01

    The paper presents the development of a sub-petawatt ultrashort laser facility, i.e. the upgraded super intense laser for experiment on the extremes (SILEX-I). The facility is a multi-stage Ti:sapphire chirped pulse amplification (CPA) laser system. Cross-polarized wave generation was used to improve the temporal contrast. An adaptive optical system was utilized to correct wavefront aberrations and to improve focusability before each shot. After upgrading, the maximum energy is 20.1 J, the recompressed pulse width is 26.8 fs and the peak power is up to 750 TW. The temporal contrast is around 109. The on-target focal spot size (full width at half maximum (FWHM)) is Φ6.5 μm and the focused intensity is greater than 4x1020 W/cm2.

  11. Development of diagnostics for high-energy petawatt pulses

    SciTech Connect

    Jovanovic, I; Hernandez, J; Appel, G; Barker, D; Betts, S; Brewer, W; Brown, C; Chang, J; Chrisp, M; Crane, J; Haefner, C; Lucianetti, A; Rushford, M; Semenov, V; Seppala, L; Shverdin, M; Siders, C; Taranowski, M; Tietbohl, G; Barty, C J

    2006-06-15

    Applications accessed by high energy petawatt (HEPW) lasers require complete, single-shot characterization of pulse spatial, temporal, and energy characteristics. We describe techniques that enable single-shot characterization of the temporal shape and pulse contrast of HEPW pulses with >10{sup 8} dynamic range over a ns-temporal window. Approaches to measure pulse durations that span two orders of magnitude will be discussed. Finally, we describe a novel implementation of spectrally dispersed two-beam interferometry for measurement of the phase difference between two HEPW pulses. This technique can be applied to dispersion and B-integral measurements in a HEPW system, as well as to achieve precise timing of nanosecond pulses. Lastly, spectrally dispersed interferometry represents an ideal technique to enable coherent addition of HEPW pulses for production of ultrahigh intensities.

  12. Multilayer Dielectric Gratings for Petawatt-Class Laser Systems

    SciTech Connect

    Britten, J A; Molander, W; Komashko, A M; Barty, C P J

    2003-12-03

    Existing Petawatt class lasers today based on Nd:glass architectures operating at nominally 500 J, 0.5 ps use meter-scale aperture, gold-overcoated master photoresist gratings to compress the amplified chirped pulse. Many lasers operating in the >lkJ, >Ips regime are in the planning stages around the world. These will require multilayer dielectric diffraction gratings to handle larger peak powers than can be accommodated with gold gratings. Models of the electric field distribution in the solid material of these gratings suggest that high aspect-ratio structures used at high incidence angles will have better laser damage resistance. New tooling for transfer etching these submicron-grating patterns and for nondestructive critical-dimension measurement of these features on meter-scale substrates will be described.

  13. A dual-channel, curved-crystal spectrograph for petawatt laser, x-ray backlighter source studies

    NASA Astrophysics Data System (ADS)

    Theobald, W.; Stoeckl, C.; Jaanimagi, P. A.; Nilson, P. M.; Storm, M.; Meyerhofer, D. D.; Sangster, T. C.; Hey, D.; MacKinnon, A. J.; Park, H.-S.; Patel, P. K.; Shepherd, R.; Snavely, R. A.; Key, M. H.; King, J. A.; Zhang, B.; Stephens, R. B.; Akli, K. U.; Highbarger, K.; Daskalova, R. L.; Van Woerkom, L.; Freeman, R. R.; Green, J. S.; Gregori, G.; Lancaster, K.; Norreys, P. A.

    2009-08-01

    A dual-channel, curved-crystal spectrograph was designed to measure time-integrated x-ray spectra in the ˜1.5 to 2 keV range (6.2-8.2 Å wavelength) from small-mass, thin-foil targets irradiated by the VULCAN petawatt laser focused up to 4×1020 W/cm2. The spectrograph consists of two cylindrically curved potassium-acid-phthalate crystals bent in the meridional plane to increase the spectral range by a factor of ˜10 compared to a flat crystal. The device acquires single-shot x-ray spectra with good signal-to-background ratios in the hard x-ray background environment of petawatt laser-plasma interactions. The peak spectral energies of the aluminum Heα and Lyα resonance lines were ˜1.8 and ˜1.0 mJ/eV sr (˜0.4 and 0.25 J/Å sr), respectively, for 220 J, 10 ps laser irradiation.

  14. A Dual-Channel, Curved-Crystal Spectrograph for Petawatt Laser, X-Ray Backlighter Source Studies

    SciTech Connect

    Theobald, W.; Stoeckl, C.; Jaanimagi, P.A.; Nilson, P.M.; Storm, M.; Meyerhofer, D.D.; Sangster, T.C.; Hey, D.; MacKinnon, A.J.; Park, H.-S.; Patel, P.K.; Shepherd, R.; Snavely, R.A.; Key, M.H.; King, J.A.; Zhang, B.; Stephens, R.B.; Akli, K.U.; Highbarger, K.; Daskalova, R.L.; VanWoerkom, L.; Freeman, R.R.; Green, J.S.; Gregori, G.; Lancaster, K.; Norreys, P.A.

    2009-08-19

    A dual-channel, curved-crystal spectrograph was designed to measure time-integrated x-ray spectra in the ~1.5 to 2 keV range (6.2–8.2 Å wavelength) from small-mass, thin-foil targets irradiated by the VULCAN petawatt laser focused up to 4 x 10^20 W/cm^2. The spectrograph consists of two cylindrically curved potassium-acid-phthalate crystals bent in the meridional plane to increase the spectral range by a factor of ~10 compared to a flat crystal. The device acquires single-shot x-ray spectra with good signal-to-background ratios in the hard x-ray background environment of petawatt laser-plasma interactions. The peak spectral energies of the aluminum He-alpha and Ly-alpha resonance lines were ~1.8 and ~1.0 mJ/eV sr (~0.4 and 0.25 J/Å sr), respectively, for 220 J, 10 ps laser irradiation.

  15. A dual-channel, curved-crystal spectrograph for petawatt laser, x-ray backlighter source studies

    SciTech Connect

    Theobald, W.; Stoeckl, C.; Jaanimagi, P. A.; Nilson, P. M.; Storm, M.; Meyerhofer, D. D.; Sangster, T. C.; Hey, D.; MacKinnon, A. J.; Park, H.-S.; Patel, P. K.; Shepherd, R.; Snavely, R. A.; Key, M. H.; King, J. A.; Zhang, B.; Stephens, R. B.; Akli, K. U.; Highbarger, K.; Daskalova, R. L.; and others

    2009-08-15

    A dual-channel, curved-crystal spectrograph was designed to measure time-integrated x-ray spectra in the {approx}1.5 to 2 keV range (6.2-8.2 A wavelength) from small-mass, thin-foil targets irradiated by the VULCAN petawatt laser focused up to 4x10{sup 20} W/cm{sup 2}. The spectrograph consists of two cylindrically curved potassium-acid-phthalate crystals bent in the meridional plane to increase the spectral range by a factor of {approx}10 compared to a flat crystal. The device acquires single-shot x-ray spectra with good signal-to-background ratios in the hard x-ray background environment of petawatt laser-plasma interactions. The peak spectral energies of the aluminum He{sub {alpha}} and Ly{sub {alpha}} resonance lines were {approx}1.8 and {approx}1.0 mJ/eV sr ({approx}0.4 and 0.25 J/A sr), respectively, for 220 J, 10 ps laser irradiation.

  16. Generation of multi-hundred petawatt pulses by resonant Raman amplification in plasma

    NASA Astrophysics Data System (ADS)

    Wu, Zhaohui; Zuo, Yanlei; Su, Jingqin; Liu, Lanqin; Zhang, Zhimeng; Li, Zhilin; Jiao, Zhihong; Wei, Xiaofeng

    2015-03-01

    Backward Raman amplification (BRA) in plasma has been proposed to produce overcritical high-power laser pulses. In this paper, an application based on CPA and BRA is promoted to generate multi-hundred petawatt laser pulses. The compression of short-wavelength (around 351 nm) and picosecond pulses has been proposed for high output intensity and short plasma length. This principle was employed in an application and a scheme is demonstrated using a full-kinetic particle-in-cell (PIC) code. The PIC code is also used to optimize key parameters in the resonant interaction. According to the simulated result using optimized parameters, the output seed fluence is amplified to 6.5 kJ/cm2 and the full-width at half-maximum duration is compressed to 13 fs, showing an energy transfer over 60%. Extending the result to the multidimensional case, a total energy of 3.9 kJ and a laser power of 300 PW are achievable, in a 0.6 cm2 interaction spot. This result is helpful for the improvement of high-energy density physics.

  17. Ultra-intense Pair Creation using the Texas Petawatt Laser and Applications

    NASA Astrophysics Data System (ADS)

    Liang, Edison; Henderson, Alexander; Clarke, Taylor; Lo, Willie; Chaguine, Petr; Dyer, Gilliss; Riley, Nathan; Serratto, Kristina; Donovan, Michael; Ditmire, Todd

    2014-10-01

    Pair plasmas and intense gamma-ray sources are ubiquitous in the high-energy universe, from pulser winds to gamma-ray bursts (GRB). Their study can be greatly enhanced if such sources can be recreated in the laboratory under controlled conditions. In 2012 and 2013, a joint Rice-University of Texas team performed over 130 laser shots on thick gold and platinum targets using the 100 Joule Texas Petawatt Laser in Austin. The laser intensity of many shots exceeded 1021 W.cm-2 with pulses as short as 130 fs. These experiments probe a new extreme regime of ultra-intense laser - high-Z solid target interactions never achieved before. In addition to creating copious pairs with the highest density (>1015/cc) and emergent e +/e- ratio exceeding 20% in many shots, these experiments also created the highest density multi-MeV gamma-rays, comparable in absolute numbers to those found inside a gamma-ray burst (GRB). Potential applications of such intense pair and gamma-ray sources to laboratory astrophysics and innovative technologies will be discussed. Work supported by DOE HEDLP program.

  18. Characteristics of High Energy Ka and Bremsstrahlung Sources Generated by Short Pulse Petawatt Lasers

    SciTech Connect

    Park, H; Izumi, N; Key, M H; Koch, J A; Landen, O L; Patel, P K; Phillips, T W; Zhang, B B

    2004-04-13

    We have measured the characteristics of high energy K{alpha} sources created with the Vulcan Petawatt laser at RAL and the JanUSP laser at LLNL. High energy x-ray backlighters will be essential for radiographing High-Energy-Density Experimental Science (HEDES) targets for NIF projects especially to probe implosions and high areal density planar samples. Hard K{alpha} x-ray photons are created through relativistic electron plasma interactions in the target material after irradiation by short pulse high intensity lasers. For our Vulcan experiment, we employed a CsI scintillator/CCD camera for imaging and a CCD camera for single photon counting. We measured the Ag K{alpha} source (22 keV) size using a pinhole array and the K{alpha} flux using a single photon counting method. We also radiographed a high Z target using the high energy broadband x-rays generated from these short pulse lasers. This paper will present results from these experiments.

  19. Acceleration of electrons under the action of petawatt-class laser pulses onto foam targets

    NASA Astrophysics Data System (ADS)

    Pugachev, L. P.; Andreev, N. E.; Levashov, P. R.; Rosmej, O. N.

    2016-09-01

    Optimization study for future experiments on interaction of petawatt laser pulses with foam targets was done by 3D PIC simulations. Densities in the range 0.5nc-nc and thicknesses in the range 100 - 500 μm of the targets were considered corresponding to those which are currently available. It is shown that heating of electrons mainly occurs under the action of the ponderomotive force of a laser pulse in which amplitude increases up to three times because of self-focusing effect in underdense plasma. Accelerated electrons gain additional energy directly from the high-frequency laser field at the betatron resonance in the emerging plasma density channels. For thicker targets a higher number of electrons with higher energies are obtained. The narrowing of the angular distribution of electrons for thicker targets is explained by acceleration in multiple narrow filaments. Obtained energies of accelerated electrons can be approximated by Maxwell distribution with the temperature 8.5 MeV. The charge carried by electrons with energies higher than 30 MeV is about 30 nC, that is 3-4 order of magnitude higher than the charge predicted by the ponderomotive scaling for the incident laser amplitude.

  20. Calibration of the neutron detectors for the cluster fusion experiment on the Texas Petawatt Laser

    SciTech Connect

    Bang, W.; Quevedo, H. J.; Dyer, G.; Rougk, J.; Kim, I.; McCormick, M.; Bernstein, A. C.; Ditmire, T.

    2012-06-15

    Three types of neutron detectors (plastic scintillation detectors, indium activation detectors, and CR-39 track detectors) were calibrated for the measurement of 2.45 MeV DD fusion neutron yields from the deuterium cluster fusion experiment on the Texas Petawatt Laser. A Cf-252 neutron source and 2.45 MeV fusion neutrons generated from laser-cluster interaction were used as neutron sources. The scintillation detectors were calibrated such that they can detect up to 10{sup 8} DD fusion neutrons per shot in current mode under high electromagnetic pulse environments. Indium activation detectors successfully measured neutron yields as low as 10{sup 4} per shot and up to 10{sup 11} neutrons. The use of a Cf-252 neutron source allowed cross calibration of CR-39 and indium activation detectors at high neutron yields ({approx}10{sup 11}). The CR-39 detectors provided consistent measurements of the total neutron yield of Cf-252 when a modified detection efficiency of 4.6 Multiplication-Sign 10{sup -4} was used. The combined use of all three detectors allowed for a detection range of 10{sup 4} to 10{sup 11} neutrons per shot.

  1. Improved pulse contrast on the Texas Petawatt Laser

    NASA Astrophysics Data System (ADS)

    Gaul, E.; Toncian, T.; Martinez, M.; Gordon, J.; Spinks, M.; Dyer, G.; Truong, N.; Wagner, C.; Tiwari, G.; Donovan, M. E.; Ditmire, T.; Hegelich, B. M.

    2016-05-01

    We have completed a pulse contrast upgrade on the Texas Petawatt Laser. This improvement enables the use of thin and reduced mass targets for ion acceleration, and reduces pre-plasma effects on all experiments. The new design starts with two BBO-based OPCPA stages pumped by an optically synchronized 8-ps laser. These stages amplify slightly chirped few ps pulses by six orders of magnitude. Next there are two LBO-based OPCPA stages that are pumped by 4 ns pulses. With much less gain than before, parametric fluorescence has been reduced by about three orders of magnitude. Prior to the upgrade, lenses caused pencil beam prepulses. Since tilting or wedging lenses was not a viable option, we replaced all lenses in the glass amplifiers with off-axis parabolic mirrors. There are still weak prepulses that we attribute to surface scattering. We eliminated thin transmissive optics to avoid post pulses that would result in prepulses by nonlinear (B-integral) conversion. This required us to reduce from eight to four passes in the 64-mm glass amplifier and to add a two-pass 25-mm “booster amplifier.” As a final upgrade we added an Acousto-Optic Programmable Dispersive-Filter (AOPDF) to improve higher order dispersion and steepen the rising edge of the compressed pulse.

  2. Laser wakefield acceleration by petawatt ultrashort laser pulses

    SciTech Connect

    Gorbunov, L.M.; Kalmykov, S.Yu.; Mora, P.

    2004-12-07

    An ultra-short (about 30 fs) petawatt laser pulse focused in a wide focal spot (about 100{mu}m) in rarefied plasma (n0 {approx} 1017cm-3) excites a nonlinear plasma wakefield which can accelerate injected electrons up to a GeV energy without pulse channelling. In these conditions, the laser pulse with an over-critical power for relativistic self-focusing propagates as in vacuum. The nonlinear quasi-plane wake plasma wave, whose amplitude and phase velocity vary along the laser path, effectively traps and accelerates injected electrons with a wide range of initial energies. Electrons accelerated along two Rayleigh lengths (about eight centimeters) gain the energy up to 1 GeV. In particular, the electrons trapped from quite a long ({tau}b {approx} 330 fs) non-resonant electron beamlet of 1 MeV particles eventually form a low emittance bunch with the energies in the range 900 {+-} 50 MeV. All these conclusions follow from the two-dimensional simulations performed in cylindrical geometry by fully relativistic time-averaged particle code WAKE.

  3. Z-petawatt driven ion beam radiography development.

    SciTech Connect

    Schollmeier, Marius; Geissel, Matthias; Rambo, Patrick K.; Schwarz, Jens; Sefkow, Adam B.

    2013-09-01

    Laser-driven proton radiography provides electromagnetic field mapping with high spatiotemporal resolution, and has been applied to many laser-driven High Energy Density Physics (HEDP) experiments. Our report addresses key questions about the feasibility of ion radiography at the Z-Accelerator (%E2%80%9CZ%E2%80%9D), concerning laser configuration, hardware, and radiation background. Charged particle tracking revealed that radiography at Z requires GeV scale protons, which is out of reach for existing and near-future laser systems. However, it might be possible to perform proton deflectometry to detect magnetic flux compression in the fringe field region of a magnetized liner inertial fusion experiment. Experiments with the Z-Petawatt laser to enhance proton yield and energy showed an unexpected scaling with target thickness. Full-scale, 3D radiation-hydrodynamics simulations, coupled to fully explicit and kinetic 2D particle-in-cell simulations running for over 10 ps, explain the scaling by a complex interplay of laser prepulse, preplasma, and ps-scale temporal rising edge of the laser.

  4. Selective deuterium ion acceleration using the Vulcan petawatt laser

    SciTech Connect

    Krygier, A. G.; Morrison, J. T.; Kar, S. Ahmed, H.; Alejo, A.; Green, A.; Jung, D.; Clarke, R.; Notley, M.; Fuchs, J.; Vassura, L.; Kleinschmidt, A.; Roth, M.; Najmudin, Z.; Nakamura, H.; Norreys, P.; Oliver, M.; Zepf, M.; Borghesi, M.; Freeman, R. R.

    2015-05-15

    We report on the successful demonstration of selective acceleration of deuterium ions by target-normal sheath acceleration (TNSA) with a high-energy petawatt laser. TNSA typically produces a multi-species ion beam that originates from the intrinsic hydrocarbon and water vapor contaminants on the target surface. Using the method first developed by Morrison et al. [Phys. Plasmas 19, 030707 (2012)], an ion beam with >99% deuterium ions and peak energy 14 MeV/nucleon is produced with a 200 J, 700 fs, >10{sup 20}W/cm{sup 2} laser pulse by cryogenically freezing heavy water (D{sub 2}O) vapor onto the rear surface of the target prior to the shot. Within the range of our detectors (0°–8.5°), we find laser-to-deuterium-ion energy conversion efficiency of 4.3% above 0.7 MeV/nucleon while a conservative estimate of the total beam gives a conversion efficiency of 9.4%.

  5. Design of a {O}94 cm mirror mount for the Petawatt Project on Nova

    SciTech Connect

    Hamilton, R.; Tietbohl, G.L.

    1995-10-01

    The authors have designed a large optical gimbal mount that will be used on the Petawatt Project currently under construction on the Nova laser. These mounts are designed to hold and tilt {O}94 cm mirrors and gratings that will redirect the {O}60 cm beam through the Petawatt vacuum compressor. Lacking the commercial availability to house this size optic, they have engineered a large mirror mount with a high natural frequency (42 Hz), low self-weight deflection of the mirror (< {lambda}/46), and high positioning accuracy characteristics (< 1 {micro}rad using flexures and stepping motors). Analysis details and methodology are presented.

  6. High-Intensity Laser Interactions with Mass-Limited Solid Targets and Implications for Fast-Ignition Experiments on OMEGA EP

    SciTech Connect

    Myatt, J.; Theobald, W.; Delettrez, J.A.; Stoeckl, C.; Storm, M.; Sangster, T.C.; Maximov, A.V.; Short, R.W.

    2007-03-23

    The modeling of petawatt laser-generated hot electrons in mass-limited solid-foil-target interactions at "relativistic" laser intensities is presented using copper targets and parameters motivated by recent experiments at the Rutherford Appleton Laboratory Petawatt and 100-TW facilities. Electron refluxing allows a unique determination of the laser-electron conversion efficiency and a test with simulations.

  7. A Focal-Spot Diagnostic for On-Shot Characterization of High-Energy Petawatt Lasers

    SciTech Connect

    Bromage, J.; Bahk, S.-W.; Irwin, D.; Kwiatkowski, J.; Pruyne, A.; Millecchia, M.; Moore, M.; Zuegel, J.D.

    2008-10-07

    An on-shot focal-spot diagnostic for characterizing high-energy, petawatt-class laser systems is presented. Accurate measurements at full energy are demonstrated using high-resolution wavefront sensing in combination with techniques to calibrate on-shot measurements with low-power sample beams. Results are shown for full-energy activation shots of the OMEGA EP Laser System.

  8. Architecture of petawatt-class z-pinch accelerators

    NASA Astrophysics Data System (ADS)

    Stygar, W. A.; Cuneo, M. E.; Headley, D. I.; Ives, H. C.; Leeper, R. J.; Mazarakis, M. G.; Olson, C. L.; Porter, J. L.; Wagoner, T. C.; Woodworth, J. R.

    2007-03-01

    We have developed an accelerator architecture that can serve as the basis of the design of petawatt-class z-pinch drivers. The architecture has been applied to the design of two z-pinch accelerators, each of which can be contained within a 104-m-diameter cylindrical tank. One accelerator is driven by slow (˜1μs) Marx generators, which are a mature technology but which necessitate significant pulse compression to achieve the short pulses (≪1μs) required to drive z pinches. The other is powered by linear transformer drivers (LTDs), which are less mature but produce much shorter pulses than conventional Marxes. Consequently, an LTD-driven accelerator promises to be (at a given pinch current and implosion time) more efficient and reliable. The Marx-driven accelerator produces a peak electrical power of 500 TW and includes the following components: (i) 300 Marx generators that comprise a total of 1.8×104 capacitors, store 98 MJ, and erect to 5 MV; (ii) 600 water-dielectric triplate intermediate-store transmission lines, which also serve as pulse-forming lines; (iii) 600 5-MV laser-triggered gas switches; (iv) three monolithic radial-transmission-line impedance transformers, with triplate geometries and exponential impedance profiles; (v) a 6-level 5.5-m-diameter 15-MV vacuum insulator stack; (vi) six magnetically insulated vacuum transmission lines (MITLs); and (vii) a triple-post-hole vacuum convolute that adds the output currents of the six MITLs, and delivers the combined current to a z-pinch load. The accelerator delivers an effective peak current of 52 MA to a 10-mm-length z pinch that implodes in 95 ns, and 57 MA to a pinch that implodes in 120 ns. The LTD-driven accelerator includes monolithic radial transformers and a MITL system similar to those described above, but does not include intermediate-store transmission lines, multimegavolt gas switches, or a laser trigger system. Instead, this accelerator is driven by 210 LTD modules that include a total of 1

  9. Simulations of radiation pressure ion acceleration with the VEGA Petawatt laser

    NASA Astrophysics Data System (ADS)

    Stockhausen, Luca C.; Torres, Ricardo; Conejero Jarque, Enrique

    2016-09-01

    The Spanish Pulsed Laser Centre (CLPU) is a new high-power laser facility for users. Its main system, VEGA, is a CPA Ti:Sapphire laser which, in its final phase, will be able to reach Petawatt peak powers in pulses of 30 fs with a pulse contrast of 1 :1010 at 1 ps. The extremely low level of pre-pulse intensity makes this system ideally suited for studying the laser interaction with ultrathin targets. We have used the particle-in-cell (PIC) code OSIRIS to carry out 2D simulations of the acceleration of ions from ultrathin solid targets under the unique conditions provided by VEGA, with laser intensities up to 1022 W cm-2 impinging normally on 20 - 60 nm thick overdense plasmas, with different polarizations and pre-plasma scale lengths. We show how signatures of the radiation pressure-dominated regime, such as layer compression and bunch formation, are only present with circular polarization. By passively shaping the density gradient of the plasma, we demonstrate an enhancement in peak energy up to tens of MeV and monoenergetic features. On the contrary linear polarization at the same intensity level causes the target to blow up, resulting in much lower energies and broader spectra. One limiting factor of Radiation Pressure Acceleration is the development of Rayleigh-Taylor like instabilities at the interface of the plasma and photon fluid. This results in the formation of bubbles in the spatial profile of laser-accelerated proton beams. These structures were previously evidenced both experimentally and theoretically. We have performed 2D simulations to characterize this bubble-like structure and report on the dependency on laser and target parameters.

  10. Simulations of ion acceleration from ultrathin targets with the VEGA petawatt laser

    NASA Astrophysics Data System (ADS)

    Stockhausen, Luca C.; Torres, Ricardo; Conejero Jarque, Enrique

    2015-05-01

    The Spanish Pulsed Laser Centre (CLPU) is a new high-power laser facility for users. Its main system, VEGA, is a CPA Ti:Sapphire laser which, in its final phase, will be able to reach petawatt peak powers in pulses of 30 fs with a pulse contrast of 1 : 1010 at 1 ps. The extremely low level of pre-pulse intensity makes this system ideally suited for studying the laser interaction with ultrathin targets. We have used the particle-in-cell (PIC) code OSIRIS to carry out 2D simulations of the acceleration of ions from ultrathin solid targets under the unique conditions provided by VEGA, with laser intensities up to 1022Wcm-2 impinging normally on 5 - 40 nm thick overdense plasmas, with different polarizations and pre-plasma scale lengths. We show how signatures of the radiation pressure dominated regime, such as layer compression and bunch formation, are only present with circular polarization. By passively shaping the density gradient of the plasma, we demonstrate an enhancement in peak energy up to tens of MeV and monoenergetic features. On the contrary linear polarization at the same intensity level causes the target to blow up, resulting in much lower energies and broader spectra. One limiting factor of Radiation Pressure Acceleration is the development of Rayleigh-Taylor like instabilities at the interface of the plasma and photon fluid. This results in the formation of bubbles in the spatial profile of laser-accelerated proton beams. These structures were previously evidenced both experimentally and theoretically. We have performed 2D simulations to characterize this bubble-like structure and report on the dependency on laser and target parameters.

  11. Fiber laser front end for high energy petawatt laser systems

    SciTech Connect

    Dawson, J W; Messerly, M J; Phan, H; Mitchell, S; Drobshoff, A; Beach, R J; Siders, C; Lucianetti, A; Crane, J K; Barty, C J

    2006-06-15

    We are developing a fiber laser front end suitable for high energy petawatt laser systems on large glass lasers such as NIF. The front end includes generation of the pulses in a fiber mode-locked oscillator, amplification and pulse cleaning, stretching of the pulses to >3ns, dispersion trimming, timing, fiber transport of the pulses to the main laser bay and amplification of the pulses to an injection energy of 150 {micro}J. We will discuss current status of our work including data from packaged components. Design detail such as how the system addresses pulse contrast, dispersion trimming and pulse width adjustment and impact of B-integral on the pulse amplification will be discussed. A schematic of the fiber laser system we are constructing is shown in figure 1 below. A 40MHz packaged mode-locked fiber oscillator produces {approx}1nJ pulses which are phase locked to a 10MHz reference clock. These pulses are down selected to 100kHz and then amplified while still compressed. The amplified compressed pulses are sent through a non-linear polarization rotation based pulse cleaner to remove background amplified spontaneous emission (ASE). The pulses are then stretched by a chirped fiber Bragg grating (CFBG) and then sent through a splitter. The splitter splits the signal into two beams. (From this point we follow only one beam as the other follows an identical path.) The pulses are sent through a pulse tweaker that trims dispersion imbalances between the final large optics compressor and the CFBG. The pulse tweaker also permits the dispersion of the system to be adjusted for the purpose of controlling the final pulse width. Fine scale timing between the two beam lines can also be adjusted in the tweaker. A large mode area photonic crystal single polarization fiber is used to transport the pulses from the master oscillator room to the main laser bay. The pulses are then amplified a two stage fiber amplifier to 150mJ. These pulses are then launched into the main amplifier

  12. Ultra-Intense Short-Pulse Pair Creation Using the Texas Petawatt Laser

    NASA Astrophysics Data System (ADS)

    Liang, Edison; Henderson, Alexander; Clarke, Taylor; Taylor, Devin; Chaguine, Petr; Serratto, Kristina; Riley, Nathan; Dyer, Gilliss; Donovan, Michael; Ditmire, Todd

    2013-10-01

    We report results from the 2012 pair creation experiment using the Texas Petawatt Laser. Up to 1011 positrons per steradian were detected using 100 Joule pulses from the Texas Petawatt Laser to irradiate gold targets, with peak laser intensities up to 1.9 × 1021W/cm2 and pulse durations as short as 130 fs. Positron-to-electron ratios exceeding 20% were measured on some shots. The positron energy, positron yield per unit laser energy, and inferred positron density are significantly higher than those reported in previous experiments. This confirms that, for a given laser energy, higher intensity and shorter pulses irradiating thicker targets are more favorable for pair creation. Narrow-band high-energy positrons up to 23 MeV were observed from thin targets. Supported by DOE Grant DE-SC-0001481 and Rice FIF.

  13. Contrast and Intensity upgrades to the Texas Petawatt laser for hadron generation and non-linear QED experiments

    NASA Astrophysics Data System (ADS)

    Hegelich, Bjorn M.; Arefiev, Alexey; Ditmire, Todd; Donovan, Michael E.; Dyer, Gillis; Gaul, Erhard; Labun, Lance; Luedtke, Scott; Martinez, Mikael; McCarry, Edward; Stark, David; Pomerantz, Ishay; Tiwari, Ganesh; Toncian, Toma

    2015-11-01

    Advances in laser-based hadron generation, especially with respect to particle energy, as well as reaching the new regime of radiation dominated plasmas and non-linear QED, require laser fields of Petavolts per meter that preferably interact with very high density, overcritical plasmas. To achieve these conditions we are upgrading the Texas Petawatt Laser both respect to on-target laser intensity and laser-contrast, aiming to reach intensities of ~ 5x1022 W/cm2 and pulse contrast parameters allowing the interaction with overcritical, yet ultrathin, sub-micron targets. We will report on the planned experiments aimed at ion acceleration, neutron generation and the first experimental measurement of radiation reactions to motivate the chosen upgrade parameters. We will further report on the technical changes to the laser and present first measurements of the achieved intensity and contrast parameters. This work was supported by NNSA cooperative agreement DE-NA0002008, the Defense Advanced Research Projects Agency's PULSE program (12-63-PULSE-FP014), the Air Force Office of Scientific Research (FA9550-14-1-0045) and the National Institute of Health SBIR.

  14. A focal-spot diagnostic for on-shot characterization of high-energy petawatt lasers.

    PubMed

    Bromage, J; Bahk, S-W; Irwin, D; Kwiatkowski, J; Pruyne, A; Millecchia, M; Moore, M; Zuegel, J D

    2008-10-13

    An on-shot focal-spot diagnostic for characterizing high-energy, petawatt-class laser systems is presented. Accurate measurements at full energy are demonstrated using high-resolution wavefront sensing in combination with techniques to calibrate on-shot measurements with low-power sample beams. Results are shown for full-energy activation shots of the OMEGA EP Laser System. PMID:18852765

  15. Alignment of a petawatt-class pulse compressor with the third-order dispersion completely compensated

    NASA Astrophysics Data System (ADS)

    Zuo, Yanlei; Zhou, Kainan; Wu, Zhaohui; Wang, Xiao; Xie, Na; Su, Jingqin; Zeng, Xiaoming

    2016-05-01

    It is necessary to eliminate third-order dispersion to acquire an ultrashort pulse of less than 30 fs. We demonstrate for the first time, to the best of our knowledge, the alignment of a petawatt-class laser compressor using the equiphase lines in the spatial and spectral interference patterns. Third-order dispersion has been completely eliminated and a Fourier-transform-limited pulsewidth of 19.6 fs has been approached.

  16. Preparation For Laser Wakefield Experiments Driven by the Texas Petawatt Laser System

    SciTech Connect

    Reed, S. A.; Kalmykov, S.; Gaul, E.; Martinez, M.; Henderson, W.; Dong, P.; Gao, X.; Sanders, J. C.; Wang, X.; Shvets, G.; Ditmire, T.; Downer, M.

    2009-01-22

    Laboratories around the world are planning petawatt laser driven experiments. The Texas petawatt laser offers the ability to demonstrate laser wake field acceleration (LWFA) in a unique regime with pulse duration ({approx}160 fs) shorter than other petawatt scale systems currently in operation or under development. By focusing the 1.25 PW, 200 J, 160 fs pulses to peak intensity {approx}10{sup 19} W/cm{sup 2}, multi-GeV electron bunches can be produced from a low density He gas jet. The rarefied plasma density (5x10{sup 16}-10{sup 17} cm{sup -3}) required for near-resonant LWFA minimizes plasma lensing and offers long dephasing length for electron acceleration over distances ({approx}10 cm) exceeding the Rayleigh range. Because of the high power, the laser can be focused to a spot (r{sub 0}{approx}100 microns) greater than the plasma wavelength (r{sub 0}>{lambda}{sub p}), thus minimizing radial propagation effects. Together these properties enable the laser pulse to self-guide without the use of a preformed channel lending simplicity and stability to the overall acceleration process. Particle-in-cell (PIC) simulations show the laser experiences self-focusing which, because of ultrashort pulse duration, does not lead to a collapse of the wakefield and can generate over 3 GeV electron energy. The presented material will include details of initial measurements of the Texas petawatt laser system, simulations of laser wakefield acceleration for the given laser parameters and the experimental setup currently under construction.

  17. Hot surface ionic line emission and cold K-inner shell emission from petawatt-laser irradiated Cu foil targets

    SciTech Connect

    Theobald, W; Akli, K; Clarke, R; Delettrez, J A; Freeman, R R; Glenzer, S; Green, J; Gregori, G; Heathcote, R; Izumi, N; King, J A; Koch, J A; Kuba, J; Lancaster, K; MacKinnon, A J; Key, M; Mileham, C; Myatt, J; Neely, D; Norreys, P A; Park, H; Pasely, J; Patel, P; Regan, S P; Sawada, H; Shepherd, R; Snavely, R; Stephens, R B; Stoeckl, C; Storm, M; Zhang, B; Sangster, T C

    2005-12-13

    A hot, T{sub e} {approx} 2- to 3-keV surface plasma was observed in the interaction of a 0.7-ps petawatt laser beam with solid copper-foil targets at intensities >10{sup 20} W/cm{sup 2}. Copper K-shell spectra were measured in the range of 8 to 9 keV using a single-photon-counting x-ray CCD camera. In addition to K{sub {alpha}} and K{sub {beta}} inner-shell lines, the emission contained the Cu He{sub {alpha}} and Ly{sub {alpha}} lines, allowing the temperature to be inferred. These lines have not been observed previously with ultrafast laser pulses. For intensities less than 3 x 10{sup 18} W/cm{sup 2}, only the K{sub {alpha}} and K{sub {beta}} inner-shell emissions are detected. Measurements of the absolute K{sub {alpha}} yield as a function of the laser intensity are in agreement with a model that includes refluxing and confinement of the suprathermal electrons in the target volume.

  18. High-Order Harmonic And Fast Ion Generation In High Intensity Laser-Solid Interactions

    SciTech Connect

    Loch, R. A.; Boller, K.-J.; Martin, Ph.; Ceccotti, T.; Monot, P.; Quere, F.; George, H.; Bougeard, M.; Reau, F.; D'Oliveira, P.

    2009-07-25

    Experiments on high-order harmonic generation and ion acceleration are performed with the new installed 100 TW, 25 fs laser in Saclay (UHI100). These experiments require a very high laser pulse contrast. The suppression of prepulse energy is achieved by using a double plasma mirror, which results in a contrast of 10{sup 13}.

  19. Fast ion emission and parametric instabilities in laser-solid target interaction

    NASA Astrophysics Data System (ADS)

    Curcio, A.; Andreoli, P.; Barbarino, M.; Bonasera, A.; Cipriani, M.; Consoli, F.; Cristofari, G.; De Angelis, R.; Di Giorgio, G.; Galletti, M.; Giulietti, D.; Ingenito, F.

    2016-04-01

    The spectrum of the accelerated ions at the laser ABC of ENEA research institute, detected by time of flight measurements, is correlated to the onset of parametric instabilities, evidenced by optical diagnostics. In fact, the emission of the laser harmonics, 2ω and 3/2ω, in the visible spectrum manifests the existence, inside the inhomogeneous plasma, of regions in which electron plasma waves can be generated. These waves are the tool for the production of a supra-thermal electron population, responsible for the creation of an electric potential at the plasma sheath, which drives the ion acceleration.

  20. Injection and transport properties of fast electrons in ultraintense laser-solid interactions

    SciTech Connect

    Coury, M.; Carroll, D. C.; Yuan, X. H.; Gray, R. J.; MacLellan, D. A.; Powell, H.; Quinn, M. N.; Tresca, O.; McKenna, P.; Robinson, A. P. L.; Lancaster, K. L.; Neely, D.; Brenner, C. M.; Burza, M.; Wahlstroem, C.-G.; Li, Y. T.; Lin, X. X.

    2013-04-15

    Fast electron injection and transport in solid foils irradiated by sub-picosecond-duration laser pulses with peak intensity equal to 4 Multiplication-Sign 10{sup 20} W/cm{sup 2} is investigated experimentally and via 3D simulations. The simulations are performed using a hybrid-particle-in-cell (PIC) code for a range of fast electron beam injection conditions, with and without inclusion of self-generated resistive magnetic fields. The resulting fast electron beam transport properties are used in rear-surface plasma expansion calculations to compare with measurements of proton acceleration, as a function of target thickness. An injection half-angle of {approx}50 Degree-Sign -70 Degree-Sign is inferred, which is significantly larger than that derived from previous experiments under similar conditions.

  1. Laser-solid interaction and dynamics of laser-ablated materials

    SciTech Connect

    Chen, K.R.; Neboeuf, J.N.; Wood, R.F.; Geohegan, D.B.; Donato, J.M.; Liu, C.L.; Puretzky, A.A.

    1995-09-01

    An annealing model is extended to treat the vaporization process, and a hydrodynamic model describes the ablated material. We find that dynamic source and ionization effects accelerate the expansion front of the ablated plume with thermal vaporization temperature. The vaporization process and plume propagation in high background gas pressure are studied.

  2. High repetition rate relativistic electron beam generation from intense laser solid interactions

    NASA Astrophysics Data System (ADS)

    Batson, Thomas; Nees, John; Hou, Bixue; Thomas, Alexander; Krushelnick, Karl

    2014-10-01

    Relativistic electron beams have wide-ranging applications in medicine, materials science, and homeland security. Recent advances in short pulse laser technology have enabled the production of very high focused intensities at kHz rep rates. Consequently this has led to the generation of high flux sources of relativistic electrons - which is a necessary characteristic of these laser plasma sources for any potential application. In our experiments, through the generation of a plasma by focusing a 5 × 1018 W/cm2, 500 Hz, Ti:Sapphire laser pulse onto a fused silica target, we have measured electrons ejected from the target surface having energies in excess of an MeV. The spectrum of these electrons, as well as the spatial divergence of the resulting beam, was also measured with respect to incident laser angle, prepulse timing and focusing conditions. The experimental results are compared to particle in cell simulations.

  3. Scaling high-order harmonic generation from laser-solid interactions to ultrahigh intensity.

    PubMed

    Dollar, F; Cummings, P; Chvykov, V; Willingale, L; Vargas, M; Yanovsky, V; Zulick, C; Maksimchuk, A; Thomas, A G R; Krushelnick, K

    2013-04-26

    Coherent x-ray beams with a subfemtosecond (<10(-15)  s) pulse duration will enable measurements of fundamental atomic processes in a completely new regime. High-order harmonic generation (HOHG) using short pulse (<100  fs) infrared lasers focused to intensities surpassing 10(18)  W cm(-2) onto a solid density plasma is a promising means of generating such short pulses. Critical to the relativistic oscillating mirror mechanism is the steepness of the plasma density gradient at the reflection point, characterized by a scale length, which can strongly influence the harmonic generation mechanism. It is shown that for intensities in excess of 10(21)  W cm(-2) an optimum density ramp scale length exists that balances an increase in efficiency with a growth of parametric plasma wave instabilities. We show that for these higher intensities the optimal scale length is c/ω0, for which a variety of HOHG properties are optimized, including total conversion efficiency, HOHG divergence, and their power law scaling. Particle-in-cell simulations show striking evidence of the HOHG loss mechanism through parametric instabilities and relativistic self-phase modulation, which affect the produced spectra and conversion efficiency. PMID:23679739

  4. The Scaling of Positron Production in Intense Laser-Solid Interactions

    NASA Astrophysics Data System (ADS)

    Chen, Hui; Link, A.; Fiuza, F.; Hazi, A.; Nagel, S. R.; Park, J.; Tommasini, R.; Williams, G. J.; Sentoku, Y.; Meyerhofer, D. D.; Myatt, J. F.; Audebert, P.; Fedosejevs, R.; Kerr, S.; Hill, M.; Hoarty, D.; Hobbs, L.; James, S.

    2014-10-01

    The dependence of positron yield on laser energy was observed to be nonlinear through experiments using the laser facilities at Jupiter, OMEGA EP, and ORION for laser energies of 100 - 1500 J and intensities of 1018 -1020 Watts/cm2. The measured yield increases as ~E2, faster than that predicted by simple estimates using GEANT4. This scaling results from a combination of higher energy electrons produced at increased laser intensity and the presence of unexpected recirculation of MeV electrons in the mm-thick target. Experimental results together with analytical and Monte-Carlo simulations of the data will be presented. This work was performed under the auspices of the U.S. DOE by LLNL under Contract DE-AC52-07NA27344, and funded by LDRD (#12-ERD-062).

  5. Longitudinal proton probing of ultrafast and high-contrast laser-solid interactions

    NASA Astrophysics Data System (ADS)

    Albertazzi, B.; Antici, P.; Bocker, J.; Borghesi, M.; Chen, S.; Dervieux, V.; d'Humières, E.; Lancia, L.; Nakatsutsumi, M.; Shepherd, R.; Romagnagni, L.; Sentoku, Y.; Swantusch, M.; Willi, O.; Pépin, H.; Fuchs, J.

    2013-11-01

    We have performed an experiment aimed at measuring self-generated magnetic fields produced in solids by high electron currents following high-intensity and high contrast short-pulse laser irradiation. This was done using longitudinal high resolution proton deflectometry. The experiment was performed at the Titan-JLF laser facility with a high-power short-pulse beam (700 fs, ˜ 110 J) split into two beams irradiating two solid targets. One beam is used for the generation of protons and the other beam for the generation of the ultra-high currents of electrons and of the associated magnetic fields. This capability allows us to study the spatio-temporal evolution of the magnetic fields and its dependence on the laser intensity and target material.

  6. Magnetic reconnection and plasma dynamics in two-beam laser-solid interactions.

    PubMed

    Nilson, P M; Willingale, L; Kaluza, M C; Kamperidis, C; Minardi, S; Wei, M S; Fernandes, P; Notley, M; Bandyopadhyay, S; Sherlock, M; Kingham, R J; Tatarakis, M; Najmudin, Z; Rozmus, W; Evans, R G; Haines, M G; Dangor, A E; Krushelnick, K

    2006-12-22

    We present measurements of a magnetic reconnection in a plasma created by two laser beams (1 ns pulse duration, 1 x 10(15) W cm(-2)) focused in close proximity on a planar solid target. Simultaneous optical probing and proton grid deflectometry reveal two high velocity, collimated outflowing jets and 0.7-1.3 MG magnetic fields at the focal spot edges. Thomson scattering measurements from the reconnection layer are consistent with high electron temperatures in this region. PMID:17280361

  7. Magnetic Reconnection and Plasma Dynamics in Two-Beam Laser-Solid Interactions

    SciTech Connect

    Nilson, P. M.; Willingale, L.; Kaluza, M. C.; Kamperidis, C.; Wei, M. S.; Fernandes, P.; Kingham, R. J.; Najmudin, Z.; Haines, M. G.; Dangor, A. E.; Krushelnick, K.; Minardi, S.; Tatarakis, M.; Notley, M.; Bandyopadhyay, S.; Sherlock, M.; Evans, R. G.; Rozmus, W.

    2006-12-22

    We present measurements of a magnetic reconnection in a plasma created by two laser beams (1 ns pulse duration, 1x10{sup 15} W cm{sup -2}) focused in close proximity on a planar solid target. Simultaneous optical probing and proton grid deflectometry reveal two high velocity, collimated outflowing jets and 0.7--1.3 MG magnetic fields at the focal spot edges. Thomson scattering measurements from the reconnection layer are consistent with high electron temperatures in this region.

  8. Large-scale proton radiography with micrometer spatial resolution using femtosecond petawatt laser system

    NASA Astrophysics Data System (ADS)

    Wang, W. P.; Shen, B. F.; Zhang, H.; Lu, X. M.; Wang, C.; Liu, Y. Q.; Yu, L. H.; Chu, Y. X.; Li, Y. Y.; Xu, T. J.; Zhang, H.; Zhai, S. H.; Leng, Y. X.; Liang, X. Y.; Li, R. X.; Xu, Z. Z.

    2015-10-01

    An image of dragonfly with many details is obtained by the fundamental property of the high-energy proton source on a femtosecond petawatt laser system. Equal imaging of the dragonfly and high spatial resolution on the micrometer scale are simultaneously obtained. The head, wing, leg, tail, and even the internal tissue structures are clearly mapped in detail by the proton beam. Experiments show that image blurring caused by multiple Coulomb scattering can be reduced to a certain extent and the spatial resolution can be increased by attaching the dragonfly to the RCFs, which is consistent with theoretical assumptions.

  9. Production of Gratings for High-Energy Petawatt-Class Lasers

    SciTech Connect

    Nguyen, H T; Carlson, T C; Hoaglan, C R; Nissen, J D; Aasen, M D; Peterson, J E; Jovanovic, I; Brewer, S W; Britten, J A

    2006-06-14

    At the time of this writing, we have manufactured and delivered more than 25 multilayer dielectric diffraction gratings from 470-800 mm in long aperture for pulse compression on Petawatt-class,1-micron laser systems being built at government and university facilities in the U.S and elsewhere. We present statistics of diffraction efficiency and its spatial uniformity, diffracted wavefront, and laser damage results on witness gratings. We also discuss yield, failure modes, and manufacturing improvements necessary to improve upon the current state of the art.

  10. Development of the PETawatt Aquitaine Laser system and new perspectives in physics

    NASA Astrophysics Data System (ADS)

    Batani, D.; Koenig, M.; Miquel, J. L.; Ducret, J. E.; d'Humieres, E.; Hulin, S.; Caron, J.; Feugeas, J. L.; Nicolai, Ph; Tikhonchuk, V.; Serani, L.; Blanchot, N.; Raffestin, D.; Thfoin-Lantuejoul, I.; Rosse, B.; Reverdin, C.; Duval, A.; Laniesse, F.; Chancé, A.; Dubreuil, D.; Gastineau, B.; Guillard, J. C.; Harrault, F.; Lebœuf, D.; Le Ster, J.-M.; Pès, C.; Toussaint, J.-C.; Leboeuf, X.; Lecherbourg, L.; Szabo, C. I.; Dubois, J.-L.; Lubrano-Lavaderci, F.

    2014-05-01

    The paper describes the preparation of the short-pulse high-energy laser PETawatt Aquitaine Laser (PETAL), which will be coupled to the Laser Megajoule (LMJ) laser of CEA. The LMJ/PETAL facility will be opened for the academic access of European researchers. In parallel, diagnostics are being developed within the PETAL + project and many physical problems are being addressed ranging from the study of the problems of radiation generation and activation issues to the problem of generation of large electromagnetic pulses.

  11. Large-scale proton radiography with micrometer spatial resolution using femtosecond petawatt laser system

    SciTech Connect

    Wang, W. P.; Shen, B. F. Zhang, H.; Lu, X. M.; Wang, C.; Liu, Y. Q.; Yu, L. H.; Chu, Y. X.; Li, Y. Y.; Xu, T. J.; Zhang, H.; Zhai, S. H.; Leng, Y. X.; Liang, X. Y.; Li, R. X.; Xu, Z. Z.

    2015-10-15

    An image of dragonfly with many details is obtained by the fundamental property of the high-energy proton source on a femtosecond petawatt laser system. Equal imaging of the dragonfly and high spatial resolution on the micrometer scale are simultaneously obtained. The head, wing, leg, tail, and even the internal tissue structures are clearly mapped in detail by the proton beam. Experiments show that image blurring caused by multiple Coulomb scattering can be reduced to a certain extent and the spatial resolution can be increased by attaching the dragonfly to the RCFs, which is consistent with theoretical assumptions.

  12. Production of picosecond, kilojoule, and petawatt laser pulses via Raman amplification of nanosecond pulses.

    PubMed

    Trines, R M G M; Fiúza, F; Bingham, R; Fonseca, R A; Silva, L O; Cairns, R A; Norreys, P A

    2011-09-01

    Raman amplification in plasma has been promoted as a means of compressing picosecond optical laser pulses to femtosecond duration to explore the intensity frontier. Here we show for the first time that it can be used, with equal success, to compress laser pulses from nanosecond to picosecond duration. Simulations show up to 60% energy transfer from pump pulse to probe pulse, implying that multikilojoule ultraviolet petawatt laser pulses can be produced using this scheme. This has important consequences for the demonstration of fast-ignition inertial confinement fusion. PMID:21981507

  13. OMEGA EP: High-Energy Petawatt Capability for the OMEGA Laser Facility

    SciTech Connect

    Kelly, J.H.; Waxer, L.J.; Bagnoud, V.; Begishev, I.A.; Bromage, J.; Kruschwitz, B.E.; Kessler, T.J.; Loucks, S.J.; Maywar, D.N.; McCrory, R.L.; Meyerhofer, D.D.; Morse, S.F.B.; Oliver, J.B.; Rigatti, A.L.; Schmid, A.W.; Stoeckl, C.; Dalton, S.; Folnsbee, L.; Guardalben, M.J.; Jungquist, R.; Puth, J.; Shoup III, M.J.; Weiner, D.; Zuegel, J.D.

    2006-06-28

    OMEGA EP (Extended Performance) is a petawatt-class addition to the existing 30-kJ, 60-beam OMEGA Laser Facility at the University of Rochester. When completed, it will consist of four beamlines, each capable of producing up to 6.5 kJ at 351 nm in a 1 to 10 ns pulse. Two of the beamlines will produce up to 2.6 kJ in a pulse-width range of 1 to 100 ps at 1053 nm using chirped-pulse amplification (CPA). This paper reviews both the OMEGA EP performance objectives and the enabling technologies required to meet these goals.

  14. Ion acceleration by petawatt class laser pulses and pellet compression in a fast ignition scenario

    NASA Astrophysics Data System (ADS)

    Benedetti, C.; Londrillo, P.; Liseykina, T. V.; Macchi, A.; Sgattoni, A.; Turchetti, G.

    2009-07-01

    Ion drivers based on standard acceleration techniques have faced up to now several difficulties. We consider here a conceptual alternative to more standard schemes, such as HIDIF (Heavy Ion Driven Inertial Fusion), which are still beyond the present state of the art of particle accelerators, even though the requirements on the total beam energy are lowered by fast ignition scenarios. The new generation of petawatt class lasers open new possibilities: acceleration of electrons or protons for the fast ignition and eventually light or heavy ions acceleration for compression. The pulses of chirped pulse amplification (CPA) lasers allow ions acceleration with very high efficiency at reachable intensities ( I˜1021 W/cm2), if circularly polarized light is used since we enter in the radiation pressure acceleration (RPA) regime. We analyze the possibility of accelerating carbon ion bunches by interaction of a circularly polarized pulses with an ultra-thin target. The advantage would be compactness and modularity, due to identical accelerating units. The laser efficiency required to have an acceptable net gain in the inertial fusion process is still far from the presently achievable values both for CPA short pulses and for long pulses used for direct illumination. Conversely the energy conversion efficiency from the laser pulse to the ion bunch is high and grows with the intensity. As a consequence the energy loss is not the major concern. For a preliminary investigation of the ions bunch production we have used the PIC code ALaDyn developed to analyze the results of the INFN-CNR PLASMONX experiment at Frascati National Laboratories (Rome, Italy) where the 0.3 PW laser FLAME will accelerate electrons and protons. We present the results of some 1D simulations and parametric scan concerning the acceleration of carbon ions that we suppose to be fully ionized. Circularly polarized laser pulses of 50 J and 50-100 fs duration, illuminating a 100 μm2 area of a 20 nm thick carbon

  15. 10-kJ Status and 100-kJ Future for NIF PetaWatt Technology

    SciTech Connect

    Siders, C W; Crane, J K; Rushford, M C; Haefner, L C; Hernandez, J E; Dawson, J W; Beach, R J; Clark, W J; Trummer, D J; Tietbohl, G L; Barty, C J

    2007-07-02

    We discuss the status of the NIF ARC, an 8-beam 10-kJ class high-energy petawatt laser, and the future upgrade path of this and similar systems to 100-kJ-class with coherent phasing of multiple apertures.

  16. Characterizing relativistic petawatt-laser-generated particle beams on Orion

    NASA Astrophysics Data System (ADS)

    Hill, Matthew; Allan, Peter; Brown, Colin; Edwards, Ray; Gumbrell, Edward; Hoarty, David; Hobbs, Lauren; James, Steven; Chen, Hui; Hazi, Andy; Marley, Edward; Shepherd, Ronnie; Williams, Jackson

    2014-10-01

    The Orion laser facility at AWE has been used to irradiate a variety of metal and plastic targets with up to 600 J of 1.054 μm laser light at pulse lengths ranging from 0.5 ps to 8 ps and intensities above 1021 W/cm2. The particle beams produced from these targets include considerable numbers of relativistic electrons (up to 250 MeV) as well as positrons, protons and heavy ions (up to 60 MeV). Magnetic spectrometers, radiochromic film stacks and a Thomson parabola suggest strong sheath field acceleration of both positrons and ions, as well as very hot electron distributions (Thot >18 MeV) indicating efficient laser-plasma coupling at high intensities. Simultaneous proton radiography and heating have been accomplished on metal foils and foams, showing promise for diagnosing short-pulse laser-plasma interactions as well as fields within extended target objects. We report on the latest progress in charged particle diagnostics systems and experimental platforms on the Orion facility. Supporting work performed at LLNL under the auspices of the U.S. DoE under Contract DE-AC52-07NA27344.

  17. Blast wave diagnostic for the petawatt laser system

    SciTech Connect

    Budil, K. S., LLNL

    1998-06-03

    We report on a diagnostic to measure the trajectory of a blast wave propagating through a plastic target 400 {micro}m thick. This blast wave is generated by the irradiation of the front surface of the target with {approximately} 400 J of 1 {micro}m laser radiation in a 20 ps pulse focused to a {approximately} 50 {micro}m diameter spot, which produces an intensity in excess of 1O{sup 18} W/cm{sup 2}. These conditions approximate a point explosion and a blast wave is predicted to be generated with an initial pressure nearing 1 Gbar which decays as it travels approximately radially outward from the interaction region We have utilized streaked optical pyrometry of the blast front to determine its time of arrival at the rear surface of the target Applications of a self-similar Taylor-Sedov blast wave solution allows the amount of energy deposited to be estimated The experiment, LASNEX design simulations and initial results are discussed.

  18. High energy mode locked fiber oscillators for high contrast, high energy petawatt laser seed sources

    SciTech Connect

    Dawson, J W; Messerly, M J; An, J; Kim, D; Barty, C J

    2006-06-15

    In a high-energy petawatt laser beam line the ASE pulse contrast is directly related to the total laser gain. Thus a more energetic input pulse will result in increased pulse contrast at the target. We have developed a mode-locked fiber laser with high quality pulses and energies exceeding 25nJ. We believe this 25nJ result is scalable to higher energies. This oscillator has no intra-cavity dispersion compensation, which yields an extremely simple, and elegant laser configuration. We will discuss the design of this laser, our most recent results and characterization of all the key parameters relevant to it use as a seed laser. Our oscillator is a ring cavity mode-locked fiber laser [1]. These lasers operate in a self-similar pulse propagation regime characterized by a spectrum that is almost square. This mode was found theoretically [2] to occur only in the positive dispersion regime. Further increasing positive dispersion should lead to increasing pulse energy [2]. We established that the positive dispersion required for high-energy operation was approximately that of 2m of fiber. To this end, we constructed a laser cavity similar to [1], but with no gratings and only 2m of fiber, which we cladding pumped in order to ensure sufficient pump power was available to achieve mode-locked operation. A schematic of the laser is shown in figure 1 below. This laser produced low noise 25nJ pulses with a broad self similar spectrum (figure 2) and pulses that could be de-chirped to <100fs (figure 3). Pulse contrast is important in peta-watt laser systems. A major contributor to pulse contrast is amplified spontaneous emission (ASE), which is proportional to the gain in the laser chain. As the oscillator strength is increased, the required gain to reach 1PW pulses is decreased, reducing ASE and improving pulse contrast. We believe these lasers can be scaled in a stable fashion to pulse energies as high as 100nJ and have in fact seen 60nJ briefly in our lab, which is work still

  19. Effect of overlap rate on recrystallization behaviors of Laser Solid Formed Inconel 718 superalloy

    NASA Astrophysics Data System (ADS)

    Cao, Jun; Liu, Fencheng; Lin, Xin; Huang, Chunping; Chen, Jing; Huang, Weidong

    2013-02-01

    The effect of overlap rate on the residual stress, recrystallization nucleation location and the distribution of recrystallized grains of LSFed Inconel 718 superalloy were investigated. It is found that the as-deposited microstructures with different overlap rates have the similar characteristics including that columnar grains grow along the deposition direction. The overlap area possesses higher residual stress compared with the inner-pass area, and the position of peak residual stress is closer to previous pass. The increase in the overlap rate will broaden the variation range of the residual stress. During heat treatment, the recrystallization nucleation first occurs in the overlap area with the lower overlap rate, and then expands to both overlap area and inner-pass area paralleling with the increasing of the overlap rate. Although the overlap rate is only one of basic factors in the Laser Solid Forming process, it plays an important role in controlling residual stress distribution, material microstructure and mechanical properties. The higher overlap rate adopted, the finer and the more evenly distributed grains could be obtained through recrystallization for LSFed Inconel 718 superalloy.

  20. Measurements of electron and proton heating temperatures from extreme-ultraviolet light images at 68 eV in petawatt laser experiments

    SciTech Connect

    Gu Peimin; Zhang, B.; Key, M. H.; Hatchett, S. P.; Barbee, T.; Freeman, R. R.; Akli, K.; Hey, D.; King, J. A.; Mackinnon, A. J.; Snavely, R. A.; Stephens, R. B.

    2006-11-15

    A 68 eV extreme-ultraviolet light imaging diagnostic measures short pulse isochoric heating by electrons and protons in petawatt laser experiments. Temperatures are deduced from the absolute intensities and comparison with modeling using a radiation hydrodynamics code.

  1. Petawatt-laser direct heating of uniformly imploded deuterated-polystyrene shell target.

    PubMed

    Kitagawa, Yoneyoshi; Sentoku, Yasuhiko; Akamatsu, Shin; Sakamoto, Wataru; Tanaka, Kazuo A; Kodama, Ryosuke; Nishimura, Hiroaki; Inubushi, Yuichi; Nakai, Mitsuo; Watari, Takeshi; Norimatsu, Takayoshi; Sunahara, Atsushi

    2005-01-01

    A uniformly imploded deuterated polystyrene (CD) shell target is fast-heated by a Petawatt (PW) laser without cone guide. The best illumination timing is found to be in a narrow region around 80+/-20 picoseconds from the onset of the stagnation phase, where thermal neutrons are enhanced four to five times by the PW laser of energy less than 10% of the implosion laser. The timing agrees with the timings of enhancement of the x-ray emission from the core and reduction of the bremsstrahlung radiation from scattered hot electrons. The PW laser, focused to the critical density point, generates the energetic electrons within as narrow an angle as 30 degrees , which then heats the imploded CD shell to enhance thermal neutrons. These results first demonstrate that the PW laser directly heats the imploded core without any conelike laser guide. PMID:15697731

  2. Progress in fast ignitor research with the Nova petawatt laser facility

    SciTech Connect

    Cowan, T E; Hammel , B A; Hatchett, S P; Henry, E A; Key, M H; Kilkenny, J D; Koch, J A; Langdon, A B; Lasinski, B F; Lee, R W; Moody, J D; Mora, M J; Offenberger, A A; Pennington, D M; Perry, M D; Phillips, T J; Sangster, T C; Singh, M S; Stoyer, M A; Tabak, M; Tsukamoto, M; Wharton, K; Wilks, S C

    1998-11-10

    The physics of fast ignition is being studied using a petawatt laser facility at the Lawrence Livermore National Laboratory. Performance of the PW laser with deformable mirror wavefront control giving intensities up to 3x10{sup 20} Wcm{sup {minus}2} is described. Measurements of the efficiency of conversion of laser energy to relativistic electrons and of their energy spectrum and angular distribution including an observed narrow beam angle of {+-}15{degree}, are reported. Heating by the electrons to near 1keV in solid density CD{sub 2} is inferred from the thermo-nuclear neutron yield. Estimates suggest an optimized gain of 300x if the National Ignition Facility were to be adapted for fast ignition.

  3. Production of petawatt laser pulses by backward Raman amplification in plasma

    NASA Astrophysics Data System (ADS)

    Wu, Zhaohui; Zuo, Yanlei; Su, Jingqin; Liu, Lanqin; Jiao, Zhihong; Wei, Xiaofeng

    2015-02-01

    Backward Raman amplification (BRA) in plasma has been demonstrated an effective way to produce high power laser pulses. However, most experiments of BRA are carried out around the pump wavelength of 800 nm. In recent years, the 1053 nm pump pulse becomes more and more essential as the development of the chirped pulse amplification (CPA) around this wavelength. Here we design an experiment of BRA with a 1053 nm, 20 ps pump pulse and a 1200 nm, 50 fs seed pulse based on the facility of XG III. The simulation results obtained by a 1-d particle-in-cell (PIC) code show that the amplified peak seed intensity of ˜ 5 × 1016 W/cm2 is obtained, with an energy transfer up to 16.8%. An output pulse of petawatt power is theoretically demonstrated feasible.

  4. Observation of Synchrotron Radiation from Electrons Accelerated in a Petawatt-Laser-Generated Plasma Cavity

    SciTech Connect

    Kneip, S.; Nagel, S. R.; Bellei, C.; Dangor, A. E.; Mangles, S. P. D.; Nilson, P. M.; Willingale, L.; Najmudin, Z.; Bourgeois, N.; Marques, J. R.; Gopal, A.; Heathcote, R.; Maksimchuk, A.; Reed, S.; Phuoc, K. Ta; Rousse, A.; Tzoufras, M.; Tsung, F. S.; Mori, W. B.; Krushelnick, K.

    2008-03-14

    The dynamics of plasma electrons in the focus of a petawatt laser beam are studied via measurements of their x-ray synchrotron radiation. With increasing laser intensity, a forward directed beam of x rays extending to 50 keV is observed. The measured x rays are well described in the synchrotron asymptotic limit of electrons oscillating in a plasma channel. The critical energy of the measured synchrotron spectrum is found to scale as the Maxwellian temperature of the simultaneously measured electron spectra. At low laser intensity transverse oscillations are negligible as the electrons are predominantly accelerated axially by the laser generated wakefield. At high laser intensity, electrons are directly accelerated by the laser and enter a highly radiative regime with up to 5% of their energy converted into x rays.

  5. Scaling to Ultra-High Intensities by High-Energy Petawatt Beam Combining

    SciTech Connect

    Siders, C W; Jovanovic, I; Crane, J; Rushford, M; Lucianetti, A; Barty, C J

    2006-06-23

    The output pulse energy from a single-aperture high-energy laser amplifier (e.g. fusion lasers such as NIF and LMJ) are critically limited by a number of factors including optical damage, which places an upper bound on the operating fluence; parasitic gain, which limits together with manufacturing costs the maximum aperture size to {approx} 40-cm; and non-linear phase effects which limits the peak intensity. For 20-ns narrow band pulses down to transform-limited sub-picosecond pulses, these limiters combine to yield 10-kJ to 1-kJ maximum pulse energies with up to petawatt peak power. For example, the Advanced Radiographic Capability (ARC) project at NIF is designed to provide kilo-Joule pulses from 0.75-ps to 50-ps, with peak focused intensity above 10{sup 19} W/cm{sup 2}. Using such a high-energy petawatt (HEPW) beamline as a modular unit, they discuss large-scale architectures for coherently combining multiple HEPW pulses from independent apertures, called CAPE (Coherent Addition of Pulses for Energy), to significantly increase the peak achievable focused intensity. Importantly, the maximum intensity achievable with CAPE increases non-linearly. Clearly, the total integrated energy grows linearly with the number of apertures N used. However, as CAPE combines beams in the focal plane by increasing the angular convergence to focus (i.e. the f-number decreases), the foal spot diameter scales inversely with N. Hence the peak intensity scales as N{sup 2}. Using design estimates for the focal spot size and output pulse energy (limited by damage fluence on the final compressor gratings) versus compressed pulse duration in the ARC system, Figure 2 shows the scaled focal spot intensity and total energy for various CAPE configurations from 1,2,4, ..., up to 192 total beams. They see from the fixture that the peak intensity for event modest 8 to 16 beam combinations reaches the 10{sup 21} to 10{sup 22} W/cm{sup 2} regime. With greater number of apertures, or with

  6. Enhancement of electron energy to the multi-GeV regime by a dual-stage laser-wakefield accelerator pumped by petawatt laser pulses.

    PubMed

    Kim, Hyung Taek; Pae, Ki Hong; Cha, Hyuk Jin; Kim, I Jong; Yu, Tae Jun; Sung, Jae Hee; Lee, Seong Ku; Jeong, Tae Moon; Lee, Jongmin

    2013-10-18

    Laser-wakefield acceleration offers the promise of a compact electron accelerator for generating a multi-GeV electron beam using the huge field gradient induced by an intense laser pulse, compared to conventional rf accelerators. However, the energy and quality of the electron beam from the laser-wakefield accelerator have been limited by the power of the driving laser pulses and interaction properties in the target medium. Recent progress in laser technology has resulted in the realization of a petawatt (PW) femtosecond laser, which offers new capabilities for research on laser-wakefield acceleration. Here, we present a significant increase in laser-driven electron energy to the multi-GeV level by utilizing a 30-fs, 1-PW laser system. In particular, a dual-stage laser-wakefield acceleration scheme (injector and accelerator scheme) was applied to boost electron energies to over 3 GeV with a single PW laser pulse. Three-dimensional particle-in-cell simulations corroborate the multi-GeV electron generation from the dual-stage laser-wakefield accelerator driven by PW laser pulses. PMID:24182273

  7. Dense blocks of energetic ions driven by multi-petawatt lasers.

    PubMed

    Weng, S M; Liu, M; Sheng, Z M; Murakami, M; Chen, M; Yu, L L; Zhang, J

    2016-01-01

    Laser-driven ion accelerators have the advantages of compact size, high density, and short bunch duration over conventional accelerators. Nevertheless, it is still challenging to simultaneously enhance the yield and quality of laser-driven ion beams for practical applications. Here we propose a scheme to address this challenge via the use of emerging multi-petawatt lasers and a density-modulated target. The density-modulated target permits its ions to be uniformly accelerated as a dense block by laser radiation pressure. In addition, the beam quality of the accelerated ions is remarkably improved by embedding the target in a thick enough substrate, which suppresses hot electron refluxing and thus alleviates plasma heating. Particle-in-cell simulations demonstrate that almost all ions in a solid-density plasma of a few microns can be uniformly accelerated to about 25% of the speed of light by a laser pulse at an intensity around 10(22) W/cm(2). The resulting dense block of energetic ions may drive fusion ignition and more generally create matter with unprecedented high energy density. PMID:26924793

  8. Dense blocks of energetic ions driven by multi-petawatt lasers

    PubMed Central

    Weng, S. M.; Liu, M.; Sheng, Z. M.; Murakami, M.; Chen, M.; Yu, L. L.; Zhang, J.

    2016-01-01

    Laser-driven ion accelerators have the advantages of compact size, high density, and short bunch duration over conventional accelerators. Nevertheless, it is still challenging to simultaneously enhance the yield and quality of laser-driven ion beams for practical applications. Here we propose a scheme to address this challenge via the use of emerging multi-petawatt lasers and a density-modulated target. The density-modulated target permits its ions to be uniformly accelerated as a dense block by laser radiation pressure. In addition, the beam quality of the accelerated ions is remarkably improved by embedding the target in a thick enough substrate, which suppresses hot electron refluxing and thus alleviates plasma heating. Particle-in-cell simulations demonstrate that almost all ions in a solid-density plasma of a few microns can be uniformly accelerated to about 25% of the speed of light by a laser pulse at an intensity around 1022 W/cm2. The resulting dense block of energetic ions may drive fusion ignition and more generally create matter with unprecedented high energy density. PMID:26924793

  9. Precision damage tests of multilayer dielectric gratings for high-energy petawatt lasers

    SciTech Connect

    Jovanovic, I; Brown, C G; Stuart, B C; Molander, W; Nielsen, N; Wattellier, B; Britten, J; Pennington, D M; Barty, C J

    2004-11-08

    The next generation of high-energy petawatt (HEPW)-class lasers will utilize multilayer dielectric diffraction gratings for pulse compression due to their high efficiency and high damage threshold for picosecond pulses. We have developed a short-pulse damage test station for accurate determination of the damage threshold of the optics used on future HEPW lasers. The design and performance of the damage test laser source, based on a highly stable, high-beam-quality optical parametric chirped-pulse amplifier, is presented. Our short-pulse damage measurement methodology and results are discussed. The damage initiation is attributed to multiphoton-induced avalanche ionization, strongly dependent on the electric field enhancement in the grating groove structure and surface defects. Measurement results of the dependence of damage threshold on the pulse width, angular dependence of damage threshold of diffraction gratings, and an investigation of short-pulse conditioning effects are presented. We report record >4 J/cm{sup 2} right section surface damage thresholds obtained on multilayer dielectric diffraction gratings at 76.5 incidence angles for 10-ps pulses.

  10. All Fiber Technology for High-Energy Petawatt Front End Laser Systems

    SciTech Connect

    Dawson, J W; Liao, Z M; Jovanovic, I; Wattellier, B; Beach, R; Payne, S A; Barty, C P J

    2003-09-05

    We are developing an all fiber front end for the next generation high-energy petawatt (HEPW) laser at Lawrence Livermore National Laboratory (LLNL). The ultimate goal of the LLNL HEPW effort is to generate 5-kJ pulses capable of compression to 5ps at 1053nm, enabling advanced x-ray backlighters and possible demonstration of fast ignition. We discuss the front-end of the laser design from the fiber master oscillator, which generates the mode-locked 20nm bandwidth initial pulses through the 10mJ output of the large flattened mode (LFM) fiber amplifier. Development of an all fiber front end requires technological breakthroughs in the key areas of the master oscillator and fiber amplification. Chirped pulse amplification in optical fibers has been demonstrated to 1mJ. Further increase is limited by the onset of stimulated Raman scattering (SRS). We have recently demonstrated a new flattened mode fiber technology, which reduces peak power for a given energy and thus the onset of SRS. Controlled experiments with 1st generation fibers yielded 0.5mJ of energy while significantly increasing the point at which nonlinear optical effects degrade the amplified pulse. In this paper we will discuss our efforts to extend this work to greater than 20mJ using our large flattened mode fiber amplifier.

  11. Dense blocks of energetic ions driven by multi-petawatt lasers

    NASA Astrophysics Data System (ADS)

    Weng, S. M.; Liu, M.; Sheng, Z. M.; Murakami, M.; Chen, M.; Yu, L. L.; Zhang, J.

    2016-02-01

    Laser-driven ion accelerators have the advantages of compact size, high density, and short bunch duration over conventional accelerators. Nevertheless, it is still challenging to simultaneously enhance the yield and quality of laser-driven ion beams for practical applications. Here we propose a scheme to address this challenge via the use of emerging multi-petawatt lasers and a density-modulated target. The density-modulated target permits its ions to be uniformly accelerated as a dense block by laser radiation pressure. In addition, the beam quality of the accelerated ions is remarkably improved by embedding the target in a thick enough substrate, which suppresses hot electron refluxing and thus alleviates plasma heating. Particle-in-cell simulations demonstrate that almost all ions in a solid-density plasma of a few microns can be uniformly accelerated to about 25% of the speed of light by a laser pulse at an intensity around 1022 W/cm2. The resulting dense block of energetic ions may drive fusion ignition and more generally create matter with unprecedented high energy density.

  12. Envelope Model Simulation of Laser Wakefield Acceleration with Realistic Laser Pulses from the Texas Petawatt

    NASA Astrophysics Data System (ADS)

    Weichman, Kathleen; Higuera, Adam; Abell, Dan; Cowan, Ben; Fazel, Neil; Cary, John; Downer, Michael

    2015-11-01

    In a laser wakefield accelerator (LWFA), diffraction of an over-focused laser pulse can provide localized electron injection, leading to the production of a monoenergetic electron bunch. While electron energies up to several GeV have been reported at the Texas Petawatt Laser facility, near-Gaussian beam simulations predict energies higher than have been observed. Experimentally measured laser profiles are non-Gaussian, indicating that closer agreement with experimental conditions is needed to predictively model this experiment. The implementation of the envelope model in the particle-in-cell code VORPAL lowers the computational cost of capturing injection dynamics during the early evolution of laser wakefields. We compare VORPAL envelope model simulations using laser pulses based on experimentally measured profiles versus a corresponding a two-Gaussian approximation. We acknowledge DOE Grants No. DE-SC0011617 and DE-SC0012444, DOE/NSF Grant No. DE-SC0012584, and the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. KW is supported by the DOE CSGF under Grant No. DE-FG02-97ER25308.

  13. Petawatt laser pulses for proton-boron high gain fusion with avalanche reactions excluding problems of nuclear radiation

    NASA Astrophysics Data System (ADS)

    Hora, Heinrich; Lalousis, Paraskevas; Giuffrida, Lorenzo; Margarone, Daniele; Korn, Georg; Eliezer, Shalom; Miley, George H.; Moustaizis, Stavros; Mourou, Gérard

    2015-05-01

    An alternative way may be possible for igniting solid density hydrogen-11B (HB11) fuel. The use of >petawatt-ps laser pulses from the non-thermal ignition based on ultrahigh acceleration of plasma blocks by the nonlinear (ponderomotive) force, has to be combined with the measured ultrahigh magnetic fields in the 10 kilotesla range for cylindrical trapping. The evaluation of measured alpha particles from HB11 reactions arrives at the conclusion that apart from the usual binary nuclear reactions, secondary reactions by an avalanche multiplication may cause the high gains, even much higher than from deuterium tritium fusion. This may be leading to a concept of clean economic power generation.

  14. Polarization-encoded chirped pulse amplification in Ti:sapphire: a way toward few-cycle petawatt lasers.

    PubMed

    Kalashnikov, Mikhail; Cao, Huabao; Osvay, Károly; Chvykov, Vladimir

    2016-01-01

    The bandwidth of titanium sapphire (Ti:Sa) laser amplifiers can be greatly broadened with shaping the spectral gain via engineering the spectral polarization of amplified pulses and using both π- and σ-cross-sections. In a proof-of-principle experiment, an amplification bandwidth exceeding 85 nm at a gain of 200 was demonstrated. The accompanying computer modeling revealed that a polarization-encoded chirped pulse amplification scheme can be scaled to higher energies and thus can produce multijoule pulses with bandwidth close to 200 nm, making few-cycle petawatt Ti:Sa systems feasible. PMID:26696149

  15. LULI 100-TW Ti:sapphire/Nd:glass laser: a first step toward a high-performance petawatt facility

    NASA Astrophysics Data System (ADS)

    Zou, Jiping; Descamps, Denise; Audebert, Patrick; Baton, S. D.; Paillard, J. L.; Pesme, Denis; Michard, Alain; Sautivet, A. M.; Timsit, H.; Migus, Arnold

    1999-07-01

    We have implemented a Ti:sapphire/mixed Nd:glass laser syste at LULI producing sub-picosecond pulses in the 100 TW power range. Focusing to a 1.5-times diffraction-limited spot results in a peak intensity on target over 1019 W/cm2. Significant experiments in particle acceleration, X-ray laser and other basic plasma physics researchers have been carried out since this implementation. This paper details the characteristics of the present set-up and the main path of progress towards a high performance petawatt facility.

  16. Progress in the growth of large scale Ti:sapphire crystals by the heat exchanger method (HEM) for petawatt class lasers

    NASA Astrophysics Data System (ADS)

    Joyce, David B.; Schmid, Frederick

    2010-04-01

    In modelocked laser systems, the shortest possible pulse width is determined by the Fourier transform of the spectral bandwidth of the pulse; the wider the spectral bandwidth, the shorter the pulse. Titanium-doped sapphire (Ti:sapphire) offers the widest gain bandwidth of any currently available laser gain material, enabling systems to deliver pulse widths shorter than 10 fs (10 -14 s). Because of the short pulse durations, the peak power can be extremely high, and therefore Ti:sapphire lasers have been at the forefront of research into ultrafast, ultrahigh power lasers. These intense ultrashort laser pulses are the light source for fundamental studies of light-matter interactions. Interesting scientific results have been achieved with these lasers in the fields of high order harmonic and short pulse X-ray generations, high density plasmas, relativistic acceleration, relativistic nonlinear optics, time resolved X-ray diffraction with unprecedented time resolution and others. Researchers have recently achieved near petawatt (10 15 W) peak power laser operation using large diameter Ti:sapphire amplifiers, and are developing higher power lasers for research into high energy physics. However, the saturation fluence of the Ti:sapphire gain medium is limited to about 1 J/cm 2. Thus, continued scale up in peak laser energy requires the scale up of high-quality Ti:sapphire crystals for laser amplifiers. Current demand is for 100 mm diameter crystals, and this requirement is projected to grow up to 250 mm diameter crystals in a few years. To address this technological bottleneck, Crystal Systems has upgraded its heat exchanger method (HEM) furnaces and fabrication and metrology to scale up the production of Ti:sapphire crystals. Currently, 175 mm diameter Ti:sapphire amplifier crystals are being fabricated from high-quality 208 mm boules.

  17. Angle-dependent modulated spectral peaks of proton beams generated in ultrashort intense laser-solid interactions

    SciTech Connect

    Su, L. N.; Hu, Z. D.; Zheng, Y.; Liu, M.; Li, Y. T. Wang, W. M.; Shen, Z. W.; Fan, H. T.; Chen, L. M.; Lu, X.; Ma, J. L.; Wang, X.; Wang, Z. H.; Wei, Z. Y.; Sheng, Z. M.; Yuan, X. H.; Zhang, J.; Xu, M. H.

    2014-09-15

    Proton acceleration from 4 μm thick aluminum foils irradiated by 30-TW Ti:sapphire laser pulses is investigated using an angle-resolved proton energy spectrometer. We find that a modulated spectral peak at ∼0.82 MeV is presented at 2.5° off the target normal direction. The divergence angle of the modulated zone is 3.8°. Two-dimensional particle-in-cell simulations reveal that self-generated toroidal magnetic field at the rear surface of the target foil is responsible for the modulated spectral feature. The field deflects the low energy protons, resulting in the modulated energy spectrum with certain peaks.

  18. Study of proton acceleration at the target front surface in laser-solid interactions by neutron spectroscopy

    SciTech Connect

    Youssef, A.; Kodama, R.; Tampo, M.

    2006-03-15

    Proton acceleration inside solid LiF and CH-LiF targets irradiated by a 450-fs, 20-J, 1053-nm laser at an intensity of 3x10{sup 18} W/cm{sup 2} has been studied via neutron spectroscopy. Neutron spectra produced through the {sup 7}Li(p,n){sup 7}Be reaction that occurs between accelerated protons, at the front surface, and background {sup 7}Li ions inside the target. From measured and calculated spectra, by three-dimensional Monte Carlo code, the maximum energy, total number, and slope temperature of the accelerated protons are investigated. The study indicates that protons originate at the front surface and are accelerated to a maximum energy that is reasonably consistent with the calculated one due to the ponderomotive force.

  19. Fast electron heating in ultra-intense laser-solid interaction by shifted Kα line fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Martinolli, E.; Koenig, M.; Santos, J. J.; Amiranoff, F.; Baton, S. D.; Batani, D.; Perelli, E.; Scianitti, F.; Gremillet, L.; Rabec, M.; Rousseaux, C.; Hall, T. A.; Key, M. H.; MacKinnon, A. J.; Koch, J. A.; Freeman, R. R.; Snavely, R. A.; King, J. A.; Andersen, C.; Hill, J. M.; Stephens, R. B.; Cowan, T. E.; Ng, A.; Ao, T.

    2002-11-01

    In the context of the fast ignition studies[1], the heating of the dense fuel by fast electrons appears to be one of the most relevant aspects currently investigated [2]. In order to estimate the energy deposition and the efficiency of the fast electron transport in solid targets, we have performed experiments on LULI and RAL high power lasers, at irradiances up to a few 10^19 W/cm^2. Shifted Kα lines from an aluminum fluorescer layer buried at different depths in multilayered targets were detected using a Bragg conical-crystal spectrograph. The results were used to infer the ionization stage of the Al layer. Monte Carlo and hybrid transport codes[3] were used to study fast electron energy release by collisions and ohmic effect. The energy coupling to the target is described within an ionization model for dense matter[4] and compared to the experimental data. Despite some uncertainties of the modeling, the results give an indication of a deep heating of the target up to 30 eV after propagation in 100 μm Al. [1] M Tabak et al., Phys. of Plasmas 1, 1626 (1994) [2] E Martinolli et al., submitted to PRL, may 2002 [3] L Gremillet et al. Phys. of Plasmas 9, 941, (2002) [4] G Chiu and A Ng, PRE 59, 1024, (1999)

  20. Generation of relativistic ions, electrons and positrons in high-intensity short-pulse laser-solid interactions

    NASA Astrophysics Data System (ADS)

    Hill, Matthew; Allan, Peter; Brown, Colin; Hobbs, Lauren; James, Steven; Oades, Kevin; Hoarty, David; Chen, Hui

    2012-10-01

    The newly-commissioned Orion laser facility at AWE Aldermaston can deliver intense (10^21 W/cm^2), short (0.6 ps) laser pulses at 1φ (1 μ m) and 3x10^20 W/cm^2 at 2φ with pulse contrasts of 10^7 and 10^13, respectively, in addition to ten 3φ, 500 J long-pulse (˜ns) beams. All can be delivered to target synchronized to ˜20 ps. We report on the production and characterization of multi-MeV protons, ions, positrons and electrons at the Orion facility using 500 J, 0.6 ps, 1φ pulses and 100 J, 0.6 ps, 2φ pulses onto both thin (20 μ m) and thick (1 mm) gold targets. Laser intensities were scanned from 10^19 to 10^21 W/cm^2 by altering pulse energy and length while maintaining a consistent focal spot size of 10 μ. Particle energies were recorded by use of a magnetic and a Thomson spectrometer, with X-ray emissions imaged using a time-integrating pinhole camera in addition to time-integrating crystal spectrometers. The implications for future experiments such as investigations into electron transport mechanisms and proton heating are briefly discussed.

  1. Operation of a Single-Photon-Counting X-Ray Charge-Coupled Device Camera Spectrometer in a Petawatt Environment

    SciTech Connect

    Stoeckl, C.; Theobald, W.; Sangster, T.C.; Key, M.H.; Patel, P.; Zhang, B.B.; Clarke, R.; Karsch, S.; Norreys, P.

    2004-10-12

    The use of a single-photon-counting x-ray CCD (charge-coupled device) camera as an x-ray spectrometer is a well-established technique in ultrashort-pulse laser experiments. In single-photon-counting mode, the pixel value of each readout pixel is proportional to the energy deposited from the incident x-ray photon. For photons below 100 keV, a significant fraction of the events deposits all the energy in a single pixel. A histogram of the pixel readout values gives a good approximation of the x-ray spectrum. This technique requires almost no alignment, but it is very sensitive to signal-to-background issues, especially in a high-energy petawatt environment.

  2. Mono-energetic ions emission by nanosecond laser solid target irradiation

    NASA Astrophysics Data System (ADS)

    Muoio, A.; Tudisco, S.; Altana, C.; Lanzalone, G.; Mascali, D.; Cirrone, G. A. P.; Schillaci, F.; Trifirò, A.

    2016-09-01

    An experimental campaign aiming to investigate the acceleration mechanisms through laser-matter interaction in nanosecond domain has been carried out at the LENS (Laser Energy for Nuclear Science) laboratory of INFN-LNS, Catania. Pure Al targets were irradiated by 6 ns laser pulses at different pumping energies, up to 2 J. Advanced diagnostics tools were used to characterize the plasma plume and ion production. We show the preliminary results of this experimental campaign, and especially the ones showing the production of multicharged ions having very narrow energy spreads.

  3. Dynamics of the wakefield of a multi-petawatt, femtosecond laser pulse in a configuration with ultrarelativistic electrons

    NASA Astrophysics Data System (ADS)

    Jovanović, D.; Fedele, R.; Belić, M.

    2014-08-01

    The wakefield excitation in an unmagnetized plasma by a multi-petawatt, femtosecond, pancake-shaped laser pulse is described both analytically and numerically in the regime with ultrarelativistic electron jitter velocities, when the plasma electrons are almost expelled from the pulse region. This is done, for the first time, in fluid theory, using a novel mathematical model that does not break down for very intense pump strengths, in contrast to the standard approach that uses the laser field envelope and the ponderomotive guiding center averaging. A three-timescale description is introduced, with the intermediate scale associated with the nonlinear phase of the electromagnetic wave and with the bending of its wave front. The evolution of the pulse and of its electrostatic wake are studied by the numerical solution in a two-dimensional geometry, with the spot diameter \\gtrsim 100\\ \\mu \\text{m} . It has revealed that the nonlocal plasma response stretches very short pulses and that those with the length of 1-2 laser wavelengths, favored by the analytic estimates obtained in the local limit, are unstable. The optimum initial pulse length exceeds 1.5{\\text{-}}2\\ \\mu \\text{m} .

  4. Compton MeV Gamma-ray Source on Texas Petawatt Laser-Driven GeV Electron Accelerator

    NASA Astrophysics Data System (ADS)

    Shaw, Joseph M.; Tsai, Hai-En; Zgadzaj, Rafal; Wang, Xiaoming; Chang, Vincent; Fazel, Neil; Henderson, Watson; Downer, M. C.; Texas Petawatt Laser Team

    2015-11-01

    Compton Backscatter (CBS) from laser wakefield accelerated (LWFA) electron bunches is a promising compact, femtosecond (fs) source of tunable high-energy photons. CBS x-rays have been produced from LWFAs using two methods: (1) retro-reflection of the LWFA drive pulse via an in-line plasma mirror (PM); (2) scattering of a counter-propagating secondary pulse split from the drive pulse. Previously MeV photons were only demonstrated by the latter method, but the former method is self-aligning. Here, using the Texas Petawatt (TPW) laser and a self-aligned near-retro-reflecting PM, we generate bright CBS γ-rays with central energies higher than 10 MeV. The 100 μm focus of TPW delivers 100 J in 100 fs pulses, with intensity 6x1018 W/cm2 (a0 =1.5), to the entrance of a 6-cm long Helium gas cell. A thin, plastic PM immediately following the gas cell exit retro-reflects the LWFA driving pulse into the oncoming 0.5 - 2 GeV electron beam to produce a directional beam of γ-rays without significant bremsstrahlung background. A Pb-filter pack on a thick, pixelated, CsI(Tl) scintillator is used to estimate the spectrum via differential transmission and to observe the beam profile. Recorded beam profiles indicate a low divergence. Department of Physics, The University of Texas at Austin

  5. Space and Time Resolved Measurements of the Heating of Solids to Ten Million Kelvin by a Petawatt Laser

    SciTech Connect

    Nakatsutsumi, M.; Davies, J.R.; Kodama, R.; Green, J.S.; Lancaster, K.L.; Akli, K.U.; Beg, F.N.; Chen, S.N.; Clark, D.; Freeman, R.R.; Gregory, C.D.; Habara, H.; Heathcote, R.; Hey, D.S.; Highbarger, K.; Jaanimagi, P.; Key, M.H.; Krushelnick, K.; Ma, T.; MacPhee, A.; MacKinnon, A.J.; Nakamura, H.; Stephens, R.B.; Storm, M.; Tampo, M.; Theobald, W.; Van Woerkom, L.; Weber, R.L.; Wei, M.S.; Woolsey, N.C.; Norreys, P.A.

    2008-04-29

    The heating of plane solid targets by the Vulcan petawatt laser at powers of 0.32-0.73 PW and intensities of up to 4 x 10^20 W cm^-2 has been diagnosed with a temporal resolution of 17 ps and a spatial resolution of 30 um, by measuring optical emission from the opposite side of the target to the laser with a streak camera. Second harmonic emission was filtered out and the target viewed at an angle to eliminate optical transition radiation. Spatial resolution was obtained by imaging the emission onto a bundle of fibre optics, arranged into a one-dimensional array at the camera entrance. The results show that a region 160 um in diameter can be heated to a temperature of ~10^7 K (kT/e ~ keV) in solid targets from 10 to 20 um thick and that this temperature is maintained for at least 20 ps, confirming the utility of PW lasers in the study of high energy density physics. Hybrid code modelling shows that magnetic field generation prevents increased target heating by electron refluxing above a certain target thickness and that the absorption of laser energy into electrons entering the solid target was between 15-30%, and tends to increase with laser energy.

  6. Operation of a single-photon-counting x-ray charge-coupled device camera spectrometer in a petawatt environment

    SciTech Connect

    Stoeckl, C.; Theobald, W.; Sangster, T.C.; Key, M.H.; Patel, P.; Zhang, B.B.; Clarke, R.; Karsch, S.; Norreys, P.

    2004-10-01

    The use of a single-photon-counting x-ray charge-coupled device (CCD) camera as an x-ray spectrometer is a well-established technique in ultrashort-pulse laser experiments. In single-photon-counting mode, the pixel value of each readout pixel is proportional to the energy deposited from the incident x-ray photon. For photons below 100 keV, a significant fraction of the events deposits all the energy in a single pixel. A histogram of the pixel readout values gives a good approximation of the x-ray spectrum. This technique requires almost no alignment, but it is very sensitive to signal-to-background issues, especially in a high-energy petawatt environment. Shielding the direct line of sight to the target was not sufficient to obtain a high-quality spectrum, for the experiments reported here the CCD camera had to be shielded from all sides with up to 10 cm of lead.

  7. Fast scaling of energetic protons generated in the interaction of linearly polarized femtosecond petawatt laser pulses with ultrathin targets

    NASA Astrophysics Data System (ADS)

    Kim, I. Jong; Pae, Ki Hong; Kim, Chul Min; Kim, Hyung Taek; Choi, Il Woo; Lee, Chang-Lyoul; Singhal, Himanshu; Sung, Jae Hee; Lee, Seong Ku; Lee, Hwang Woon; Nickles, Peter V.; Jeong, Tae Moon; Nam, Chang Hee

    2015-12-01

    Laser-driven proton/ion acceleration is a rapidly developing research field attractive for both fundamental physics and applications such as hadron therapy, radiography, inertial confinement fusion, and nuclear/particle physics. Laser-driven proton/ion beams, compared to those obtained in conventional accelerators, have outstanding features such as low emittance, small source size, ultra-short duration and huge acceleration gradient of ∼1 MeV μm-1. We report proton acceleration from ultrathin polymer targets irradiated with linearly polarized, 30-fs, 1-PW Ti:sapphire laser pulses. A maximum proton energy of 45 MeV with a broad and modulated profile was obtained when a 10-nm-thick target was irradiated at a laser intensity of 3.3 × 1020 W/cm2. The transition from slow (I1/2) to fast scaling (I) of maximum proton energy with respect to laser intensity I was observed and explained by the hybrid acceleration mechanism including target normal sheath acceleration and radiation pressure acceleration in the acceleration stage and Coulomb-explosion-assisted free expansion in the post acceleration stage.

  8. Laser-induced damage of intrinsic and extrinsic defects by picosecond pulses on multilayer dielectric coatings for petawatt-class lasers

    DOE PAGESBeta

    Negres, Raluca A.; Carr, Christopher W.; Laurence, Ted A.; Stanion, Ken; Guss, Gabe; Cross, David A.; Wegner, Paul J.; Stolz, Christopher J.

    2016-08-01

    Here, we describe a damage testing system and its use in investigating laser-induced optical damage initiated by both intrinsic and extrinsic precursors on multilayer dielectric coatings suitable for use in high-energy, large-aperture petawatt-class lasers. We employ small-area damage test methodologies to evaluate the intrinsic damage resistance of various coatings as a function of deposition methods and coating materials under simulated use conditions. In addition, we demonstrate that damage initiation by raster scanning at lower fluences and growth threshold testing are required to probe the density of extrinsic defects, which will limit large-aperture optics performance.

  9. Radiation Dose Measurement for High-Intensity Laser Interactions with Solid Targets at SLAC

    SciTech Connect

    Liang, Taiee

    2015-09-25

    A systematic study of photon and neutron radiation doses generated in high-intensity laser-solid interactions is underway at SLAC National Accelerator Laboratory. We found that these laser-solid experiments are being performed using a 25 TW (up to 1 J in 40 fs) femtosecond pulsed Ti:sapphire laser at the Linac Coherent Light Source’s (LCLS) Matter in Extreme Conditions (MEC) facility. Additionally, radiation measurements were performed with passive and active detectors deployed at various locations inside and outside the target chamber. Results from radiation dose measurements for laser-solid experiments at SLAC MEC in 2014 with peak intensity between 1018 to 7.1x1019 W/cm2 are presented.

  10. Electron Acceleration in Cavitated Channels Formed by a Petawatt Laser in Low-Density Plasma

    SciTech Connect

    Mangles, S.P.D.; Walton, B.R.; Najmudin, Z.; Dangor, A.E.; Gopal, A.; Rozmus, W.; Tatarakis, M.; Thomas, A.G.R.; Wei, M.S.; Krushelnick, K.; Tzoufras, M.; Mori, W.B.; Tsung, F.S.; Clarke, R.J.; Hernandez-Gomez, C.; Evans, R.G.; Fritzler, S.

    2005-06-24

    The spectra of energetic electrons produced by a laser interaction with underdense plasma have been measured at intensities >3x10{sup 20} W cm{sup -2}. Electron energies in excess of 300 MeV have been observed. Measurements of the transmitted laser spectrum indicate that there is no correlation between the acceleration of electrons and plasma wave production. Particle-in-cell simulations show that the laser ponderomotive force produces an ion channel. The interaction of the laser field with the nonlinear focusing force of the channel leads to electron acceleration. The majority of the electrons never reach the betatron resonance but those which gain the highest energies do so. The acceleration process exhibits a strong sensitivity to initial conditions with particles that start within a fraction of a laser wavelength following completely different trajectories and gaining markedly different energies.

  11. Three dimensional finite element modeling of laser solid freeform fabrication of cobalt alloy stellite 21 with 1.5% nanoCeO2 on the low carbon steel 1015

    NASA Astrophysics Data System (ADS)

    Fayaz, G. R.; Ebrahimi, A.; Zakeri, S. S.

    Our purpose is to model the multilayer laser solid freeform fabrication (LSFF) process for the material properties of low carbon steel 1015 for workpiece and cobalt alloy stellite 21 with 1.5 wt.% nano CeO2 as the powder particles. In this paper, transient heat transfer and mass transfer equations in laser solid freeform fabrication process are solved by Finite Element Method (FEM). In this approach, the geometry of the deposited material, temperature and thermal stress fields across the process area are predicted. For each layer the clad height is computed and computations are done by the use of MATLAB and COMSOL software.

  12. Multi-layer laser solid forming of Zr65Al7.5Ni10Cu17.5 amorphous coating: Microstructure and corrosion resistance

    NASA Astrophysics Data System (ADS)

    Gan, Yu; Wang, Wenxian; Guan, Zhuosen; Cui, Zeqin

    2015-06-01

    Multi-layer Zr65Al7.5Ni10Cu17.5 amorphous coatings were produced by laser solid forming on A283 substrate. The coatings with few pores and free of cracks had good metallurgical bonding with the substrate. The microstructural characterization, phase composition, chemical component distribution and corrosion behavior of the coatings were investigated. The results revealed that the amorphization degree increased from the substrate to the coating surface mainly due to the dilution and stir influence from the melted substrate. In the five layers coating, the volume fraction of amorphous phase in the 5th layer, 3rd layer and 1st layer was about 77%, 64% and 49% respectively. With regard to corrosion property, potentiodynamic polarization plots, Nyquist plots and the equivalent circuits were employed in 3.5 wt% sodium chloride solution. Attributing to the presence of amorphous phase and passivation, the LSF coatings exhibit excellent corrosion resistance.

  13. X-ray backlight measurement of preformed plasma by kJ-class petawatt LFEX laser

    SciTech Connect

    Ohira, Shinji; Fujioka, Shinsuke; Nagatomo, Hideo; Matsuo, Satoshi; Morio, Noboru; Kawanaka, Jyunji; Nakata, Yoshiki; Miyanaga, Noriaki; Shiraga, Hiroyuki; Nishimura, Hiroaki; Azechi, Hiroshi; Sunahara, Atsushi; Johzaki, Tomoyuki

    2012-09-15

    Foot and pedestal pulses that precede the main pulse from a high-intensity laser greatly affect laser-plasma interactions. Especially in fast ignition schemes, preceding pulses generate a plasma prior to irradiation by the main pulse. This results in a too energetic and divergent electron beam being generated in the preformed plasma, which reduces the energy coupling efficiency from the heating laser to the dense fuel core. A preformed plasma with a density scale length of 40-60 {mu}m was observed by a time- and space-resolved x-ray backlight technique using the LFEX laser system at the Institute of Laser Engineering, Osaka University. Preceding pulses (i.e., the foot and pedestal) of the LFEX were characterized by comparing observations with calculations results obtained using a two-dimension (2D) radiation-hydrodynamic simulation code. In a separate experiment, the 2D code was benchmarked with the experimentally observed hydrodynamic behavior of a gold plasma produced by a nanosecond laser pulse that mimicked foot and pedestal pulses (intensity: 1 Multiplication-Sign 10{sup 11}-1 Multiplication-Sign 10{sup 12}W/cm{sup 2}). The preceding pulses were estimated to have an intensity of 1 Multiplication-Sign 10{sup 12}-10{sup 13}W/cm{sup 2}, a duration of 2.0 ns, and a spot diameter at the target of 200-600 {mu}m by comparing the measured hydrodynamics of the preformed plasma with that calculated by the 2D hydrodynamic simulation code.

  14. Demonstration of a double chirped-pulse-amplification front-end system to improve the temporal contrast at a sub-petawatt laser

    NASA Astrophysics Data System (ADS)

    Xie, Na; Zhou, Kainan; Huang, Wanqing; Wang, Xiaodong; Sun, Li; Guo, Yi; Li, Qing

    2012-02-01

    The temporal contrast is an important factor affecting the application of ultra-intense and ultra-short lasers. In this paper, we develop a double chirped-pulse-amplification (CPA) front-end system with an intermediate nonlinear temporal pulse filter to improve the temporal contrast at a sub-petawatt Ti:sapphire laser facility, i.e. the super intense laser for experiment on the extremes (SILEX-I). The temporal pulse filter employs cross-polarized wave (XPW) generation to suppress the amplified spontaneous emission (ASE). The design output energy is 320 mJ for the front-end system. The experimental results show that the output energy of the double CPA system is 360 mJ. The ASE pedestal is suppressed significantly and the temporal contrast is improved by around three orders of magnitude.

  15. Petawatt laser-driven wakefield accelerator: All-optical electron injection via collision of laser pulses and radiation cooling of accelerated electron bunches.

    NASA Astrophysics Data System (ADS)

    Kalmykov, Serguei; Avitzour, Yoav; Yi, S. Austin; Shvets, Gennady

    2007-11-01

    We explore an electron injection into the laser wakefield accelerator (LWFA) using nearly head-on collision of the petawatt ultrashort (˜30 fs) laser pulse (driver) with a low- amplitude laser (seed) beam of the same duration and polarization. To eliminate the threat to the main laser amplifier we consider two options: (i) a frequency-shifted seed and (ii) a seed pulse propagating at a small angle to the axis. We show that the emission of synchrotron radiation due to betatron oscillations of trapped and accelerated electrons results in significant transverse cooling of quasi- monoenergetic accelerated electrons (with energies above 1 GeV). At the same time, the energy losses due to the synchrotron emission preserve the final energy spread of the electron beam. The ``dark current'' due to the electron trapping in multiple wake buckets and the effect of beam loading (wake destruction at the instant of beams collision) are discussed.

  16. Conceptual designs of two petawatt-class pulsed-power accelerators for high-energy-density-physics experiments

    SciTech Connect

    Stygar, W. A.; Awe, T. J.; Bennett, N L; Breden, E. W.; Campbell, E. M.; Clark, R. E.; Cooper, R. A.; Cuneo, M. E.; Ennis, J. B.; Fehl, D. L.; Genoni, T. C.; Gomez, M. R.; Greiser, G. W.; Gruner, F. R.; Herrmann, M. C.; Hutsel, B. T.; Jennings, C. A.; Jobe, D. O.; Jones, B. M.; Jones, M. C.; Jones, P. A.; Knapp, P. F.; Lash, J. S.; LeChien, K. R.; Leckbee, J. J.; Leeper, R. J.; Lewis, S. A.; Long, F. W.; Lucero, D. J.; Madrid, E. A.; Martin, M. R.; Matzen, M. K.; Mazarakis, M. G.; McBride, R. D.; McKee, G. R.; Miller, C. L.; Moore, J. K.; Mostrom, C. B.; Mulville, T. D.; Peterson, K. J.; Porter, J. L.; Reisman, D. B.; Rochau, G. A.; Rochau, G. E.; Rose, D. V.; Savage, M. E.; Sceiford, M. E.; Schmit, P. F.; Schneider, R. F.; Schwarz, J.; Sefkow, A. B.; Sinars, D. B.; Slutz, S. A.; Spielman, R. B.; Stoltzfus, B. S.; Thoma, C.; Vesey, R. A.; Wakeland, P. E.; Welch, D. R.; Wisher, M. L.; Woodworth, J. R.; Bailey, J. E.; Rovang, D. C.

    2015-11-30

    Here, we have developed conceptual designs of two petawatt-class pulsed-power accelerators: Z 300 and Z 800. The designs are based on an accelerator architecture that is founded on two concepts: single-stage electrical-pulse compression and impedance matching [Phys. Rev. ST Accel. Beams 10, 030401 (2007)]. The prime power source of each machine consists of 90 linear-transformer-driver (LTD) modules. Each module comprises LTD cavities connected electrically in series, each of which is powered by 5-GW LTD bricks connected electrically in parallel. (A brick comprises a single switch and two capacitors in series.) Six water-insulated radial-transmission-line impedance transformers transport the power generated by the modules to a six-level vacuum-insulator stack. The stack serves as the accelerator’s water-vacuum interface. The stack is connected to six conical outer magnetically insulated vacuum transmission lines (MITLs), which are joined in parallel at a 10-cm radius by a triple-post-hole vacuum convolute. The convolute sums the electrical currents at the outputs of the six outer MITLs, and delivers the combined current to a single short inner MITL. The inner MITL transmits the combined current to the accelerator’s physics-package load. Z 300 is 35 m in diameter and stores 48 MJ of electrical energy in its LTD capacitors. The accelerator generates 320 TW of electrical power at the output of the LTD system, and delivers 48 MA in 154 ns to a magnetized-liner inertial-fusion (MagLIF) target [Phys. Plasmas 17, 056303 (2010)]. The peak electrical power at the MagLIF target is 870 TW, which is the highest power throughout the accelerator. Power amplification is accomplished by the centrally located vacuum section, which serves as an intermediate inductive-energy-storage device. The principal goal of Z 300 is to achieve thermonuclear ignition; i.e., a fusion yield that exceeds the energy transmitted by the accelerator to the liner. 2D magnetohydrodynamic (MHD

  17. Conceptual designs of two petawatt-class pulsed-power accelerators for high-energy-density-physics experiments

    NASA Astrophysics Data System (ADS)

    Stygar, W. A.; Awe, T. J.; Bailey, J. E.; Bennett, N. L.; Breden, E. W.; Campbell, E. M.; Clark, R. E.; Cooper, R. A.; Cuneo, M. E.; Ennis, J. B.; Fehl, D. L.; Genoni, T. C.; Gomez, M. R.; Greiser, G. W.; Gruner, F. R.; Herrmann, M. C.; Hutsel, B. T.; Jennings, C. A.; Jobe, D. O.; Jones, B. M.; Jones, M. C.; Jones, P. A.; Knapp, P. F.; Lash, J. S.; LeChien, K. R.; Leckbee, J. J.; Leeper, R. J.; Lewis, S. A.; Long, F. W.; Lucero, D. J.; Madrid, E. A.; Martin, M. R.; Matzen, M. K.; Mazarakis, M. G.; McBride, R. D.; McKee, G. R.; Miller, C. L.; Moore, J. K.; Mostrom, C. B.; Mulville, T. D.; Peterson, K. J.; Porter, J. L.; Reisman, D. B.; Rochau, G. A.; Rochau, G. E.; Rose, D. V.; Rovang, D. C.; Savage, M. E.; Sceiford, M. E.; Schmit, P. F.; Schneider, R. F.; Schwarz, J.; Sefkow, A. B.; Sinars, D. B.; Slutz, S. A.; Spielman, R. B.; Stoltzfus, B. S.; Thoma, C.; Vesey, R. A.; Wakeland, P. E.; Welch, D. R.; Wisher, M. L.; Woodworth, J. R.

    2015-11-01

    We have developed conceptual designs of two petawatt-class pulsed-power accelerators: Z 300 and Z 800. The designs are based on an accelerator architecture that is founded on two concepts: single-stage electrical-pulse compression and impedance matching [Phys. Rev. ST Accel. Beams 10, 030401 (2007)]. The prime power source of each machine consists of 90 linear-transformer-driver (LTD) modules. Each module comprises LTD cavities connected electrically in series, each of which is powered by 5-GW LTD bricks connected electrically in parallel. (A brick comprises a single switch and two capacitors in series.) Six water-insulated radial-transmission-line impedance transformers transport the power generated by the modules to a six-level vacuum-insulator stack. The stack serves as the accelerator's water-vacuum interface. The stack is connected to six conical outer magnetically insulated vacuum transmission lines (MITLs), which are joined in parallel at a 10-cm radius by a triple-post-hole vacuum convolute. The convolute sums the electrical currents at the outputs of the six outer MITLs, and delivers the combined current to a single short inner MITL. The inner MITL transmits the combined current to the accelerator's physics-package load. Z 300 is 35 m in diameter and stores 48 MJ of electrical energy in its LTD capacitors. The accelerator generates 320 TW of electrical power at the output of the LTD system, and delivers 48 MA in 154 ns to a magnetized-liner inertial-fusion (MagLIF) target [Phys. Plasmas 17, 056303 (2010)]. The peak electrical power at the MagLIF target is 870 TW, which is the highest power throughout the accelerator. Power amplification is accomplished by the centrally located vacuum section, which serves as an intermediate inductive-energy-storage device. The principal goal of Z 300 is to achieve thermonuclear ignition; i.e., a fusion yield that exceeds the energy transmitted by the accelerator to the liner. 2D magnetohydrodynamic (MHD) simulations

  18. Conceptual designs of two petawatt-class pulsed-power accelerators for high-energy-density-physics experiments

    DOE PAGESBeta

    Stygar, W. A.; Awe, T. J.; Bennett, N L; Breden, E. W.; Campbell, E. M.; Clark, R. E.; Cooper, R. A.; Cuneo, M. E.; Ennis, J. B.; Fehl, D. L.; et al

    2015-11-30

    Here, we have developed conceptual designs of two petawatt-class pulsed-power accelerators: Z 300 and Z 800. The designs are based on an accelerator architecture that is founded on two concepts: single-stage electrical-pulse compression and impedance matching [Phys. Rev. ST Accel. Beams 10, 030401 (2007)]. The prime power source of each machine consists of 90 linear-transformer-driver (LTD) modules. Each module comprises LTD cavities connected electrically in series, each of which is powered by 5-GW LTD bricks connected electrically in parallel. (A brick comprises a single switch and two capacitors in series.) Six water-insulated radial-transmission-line impedance transformers transport the power generated bymore » the modules to a six-level vacuum-insulator stack. The stack serves as the accelerator’s water-vacuum interface. The stack is connected to six conical outer magnetically insulated vacuum transmission lines (MITLs), which are joined in parallel at a 10-cm radius by a triple-post-hole vacuum convolute. The convolute sums the electrical currents at the outputs of the six outer MITLs, and delivers the combined current to a single short inner MITL. The inner MITL transmits the combined current to the accelerator’s physics-package load. Z 300 is 35 m in diameter and stores 48 MJ of electrical energy in its LTD capacitors. The accelerator generates 320 TW of electrical power at the output of the LTD system, and delivers 48 MA in 154 ns to a magnetized-liner inertial-fusion (MagLIF) target [Phys. Plasmas 17, 056303 (2010)]. The peak electrical power at the MagLIF target is 870 TW, which is the highest power throughout the accelerator. Power amplification is accomplished by the centrally located vacuum section, which serves as an intermediate inductive-energy-storage device. The principal goal of Z 300 is to achieve thermonuclear ignition; i.e., a fusion yield that exceeds the energy transmitted by the accelerator to the liner. 2D magnetohydrodynamic (MHD

  19. Copper fine-structure K-shell electron impact ionization cross sections for fast-electron diagnostic in laser-solid experiments

    SciTech Connect

    Palmeri, P.; Quinet, P.; Batani, D.

    2015-03-15

    The K-shell electron impact ionization (EII) cross section, along with the K-shell fluorescence yield, is one of the key atomic parameters for fast-electron diagnostic in laser-solid experiments through the K-shell emission cross section. In addition, copper is a material that has been often used in those experiments because it has a maximum total K-shell emission yield. Furthermore, in a campaign dedicated to the modeling of the K lines of astrophysical interest (Palmeri et al., 2012), the K-shell fluorescence yields for the K-vacancy fine-structure atomic levels of all the copper isonuclear ions have been calculated. In this study, the K-shell EII cross sections connecting the ground and the metastable levels of the parent copper ions to the daughter ions K-vacancy levels considered in Palmeri et al. (2012) have been determined. The relativistic distorted-wave (DW) approximation implemented in the FAC atomic code has been used for the incident electron kinetic energies up to 10 times the K-shell threshold energies. Moreover, the resulting DW cross sections have been extrapolated at higher energies using the asymptotic form proposed by Davies et al. (2013)

  20. Copper fine-structure K-shell electron impact ionization cross sections for fast-electron diagnostic in laser-solid experiments

    NASA Astrophysics Data System (ADS)

    Palmeri, P.; Quinet, P.; Batani, D.

    2015-03-01

    The K-shell electron impact ionization (EII) cross section, along with the K-shell fluorescence yield, is one of the key atomic parameters for fast-electron diagnostic in laser-solid experiments through the K-shell emission cross section. In addition, copper is a material that has been often used in those experiments because it has a maximum total K-shell emission yield. Furthermore, in a campaign dedicated to the modeling of the K lines of astrophysical interest (Palmeri et al., 2012), the K-shell fluorescence yields for the K-vacancy fine-structure atomic levels of all the copper isonuclear ions have been calculated. In this study, the K-shell EII cross sections connecting the ground and the metastable levels of the parent copper ions to the daughter ions K-vacancy levels considered in Palmeri et al. (2012) have been determined. The relativistic distorted-wave (DW) approximation implemented in the FAC atomic code has been used for the incident electron kinetic energies up to 10 times the K-shell threshold energies. Moreover, the resulting DW cross sections have been extrapolated at higher energies using the asymptotic form proposed by Davies et al. (2013).

  1. Topology of megagauss magnetic fields and of heat-carrying electrons produced in a high-power laser-solid interaction.

    PubMed

    Lancia, L; Albertazzi, B; Boniface, C; Grisollet, A; Riquier, R; Chaland, F; Le Thanh, K-C; Mellor, Ph; Antici, P; Buffechoux, S; Chen, S N; Doria, D; Nakatsutsumi, M; Peth, C; Swantusch, M; Stardubtsev, M; Palumbo, L; Borghesi, M; Willi, O; Pépin, H; Fuchs, J

    2014-12-01

    The intricate spatial and energy distribution of magnetic fields, self-generated during high power laser irradiation (at Iλ^{2}∼10^{13}-10^{14}  W.cm^{-2}.μm^{2}) of a solid target, and of the heat-carrying electron currents, is studied in inertial confinement fusion (ICF) relevant conditions. This is done by comparing proton radiography measurements of the fields to an improved magnetohydrodynamic description that fully takes into account the nonlocality of the heat transport. We show that, in these conditions, magnetic fields are rapidly advected radially along the target surface and compressed over long time scales into the dense parts of the target. As a consequence, the electrons are weakly magnetized in most parts of the plasma flow, and we observe a reemergence of nonlocality which is a crucial effect for a correct description of the energetics of ICF experiments. PMID:25526131

  2. Fast ignition realization experiment with high-contrast kilo-joule peta-watt LFEX laser and strong external magnetic field

    NASA Astrophysics Data System (ADS)

    Fujioka, Shinsuke; Arikawa, Yasunobu; Kojima, Sadaoki; Johzaki, Tomoyuki; Nagatomo, Hideo; Sawada, Hiroshi; Lee, Seung Ho; Shiroto, Takashi; Ohnishi, Naofumi; Morace, Alessio; Vaisseau, Xavier; Sakata, Shohei; Abe, Yuki; Matsuo, Kazuki; Farley Law, King Fai; Tosaki, Shota; Yogo, Akifumi; Shigemori, Keisuke; Hironaka, Yoichiro; Zhang, Zhe; Sunahara, Atsushi; Ozaki, Tetsuo; Sakagami, Hitoshi; Mima, Kunioki; Fujimoto, Yasushi; Yamanoi, Kohei; Norimatsu, Takayoshi; Tokita, Shigeki; Nakata, Yoshiki; Kawanaka, Junji; Jitsuno, Takahisa; Miyanaga, Noriaki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Kondo, Kotaro; Bailly-Grandvaux, Mathieu; Bellei, Claudio; Santos, João Jorge; Azechi, Hiroshi

    2016-05-01

    A petawatt laser for fast ignition experiments (LFEX) laser system [N. Miyanaga et al., J. Phys. IV France 133, 81 (2006)], which is currently capable of delivering 2 kJ in a 1.5 ps pulse using 4 laser beams, has been constructed beside the GEKKO-XII laser facility for demonstrating efficient fast heating of a dense plasma up to the ignition temperature under the auspices of the Fast Ignition Realization EXperiment (FIREX) project [H. Azechi et al., Nucl. Fusion 49, 104024 (2009)]. In the FIREX experiment, a cone is attached to a spherical target containing a fuel to prevent a corona plasma from entering the path of the intense heating LFEX laser beams. The LFEX laser beams are focused at the tip of the cone to generate a relativistic electron beam (REB), which heats a dense fuel core generated by compression of a spherical deuterized plastic target induced by the GEKKO-XII laser beams. Recent studies indicate that the current heating efficiency is only 0.4%, and three requirements to achieve higher efficiency of the fast ignition (FI) scheme with the current GEKKO and LFEX systems have been identified: (i) reduction of the high energy tail of the REB; (ii) formation of a fuel core with high areal density using a limited number (twelve) of GEKKO-XII laser beams as well as a limited energy (4 kJ of 0.53-μm light in a 1.3 ns pulse); (iii) guiding and focusing of the REB to the fuel core. Laser-plasma interactions in a long-scale plasma generate electrons that are too energetic to efficiently heat the fuel core. Three actions were taken to meet the first requirement. First, the intensity contrast of the foot pulses to the main pulses of the LFEX was improved to >109. Second, a 5.5-mm-long cone was introduced to reduce pre-heating of the inner cone wall caused by illumination of the unconverted 1.053-μm light of implosion beam (GEKKO-XII). Third, the outside of the cone wall was coated with a 40-μm plastic layer to protect it from the pressure caused by imploding

  3. Multi-GeV electron beams from capillary discharge guided sub-petawatt class laser pulses in the self-trapping regime

    NASA Astrophysics Data System (ADS)

    Leemans, Wim

    2014-10-01

    Laser plasma accelerators (LPAs) can produce acceleration gradients on the order of tens to hundreds of GV/m, making them attractive as compact particle accelerators. During the past decade, quasi-monochromatic electron beams at the 1 GeV energy level have been produced using laser pulses at the 40-50 TW peak power level. With the availability of petawatt class lasers, beams up to 2 GeV have been produced from 7 cm long gas cells at UT Austin using 150 J laser pulses and at the 1 GeV level with tails extending to 3 GeV at the GIST facility in Korea. In this talk we present experimental results using the 1 Hz petawatt class BELLA laser at LBNL of the generation of multi-GeV electron beams with center energy up to 4.2 GeV, 6% rms energy spread, charge approximately 10 pC and an rms divergence around 0.3 mrad. The beams were produced from 9 cm long capillary discharge waveguide structure with a plasma density of ~ 7 ×1017cm-3 , powered by laser pulses with peak power up to 0.3 PW. Preformed plasma waveguides allow the use of lower laser power compared to unguided plasma structures to achieve the same beam energy. Detailed comparison between experiment and simulation indicates the importance of the near-field laser transverse mode quality on guiding and acceleration in the LPA. By tuning the plasma density, regimes were found where laser beams with a top hat near-field profile were guided well, and where high energy electron beams can be produced, with narrow divergence [ <0.8 mrad (FWHM)], and relatively small integrated energy spread (<10%). Provided that the slice energy spread and emittance are sufficiently low, electron beams with this energy could power x-ray free electron lasers. Future experiments will aim at increasing the beam energy to the 10 GeV level. Work supported by Office of Science, Office of HEP, US DOE Contract DE-AC02-05CH11231.

  4. Validation of modelled imaging plates sensitivity to 1-100 keV x-rays and spatial resolution characterisation for diagnostics for the "PETawatt Aquitaine Laser"

    NASA Astrophysics Data System (ADS)

    Boutoux, G.; Batani, D.; Burgy, F.; Ducret, J.-E.; Forestier-Colleoni, P.; Hulin, S.; Rabhi, N.; Duval, A.; Lecherbourg, L.; Reverdin, C.; Jakubowska, K.; Szabo, C. I.; Bastiani-Ceccotti, S.; Consoli, F.; Curcio, A.; De Angelis, R.; Ingenito, F.; Baggio, J.; Raffestin, D.

    2016-04-01

    Thanks to their high dynamic range and ability to withstand electromagnetic pulse, imaging plates (IPs) are commonly used as passive detectors in laser-plasma experiments. In the framework of the development of the diagnostics for the Petawatt Aquitaine Laser facility, we present an absolute calibration and spatial resolution study of five different available types of IP (namely, MS-SR-TR-MP-ND) performed by using laser-induced K-shell X-rays emitted by a solid silver target irradiated by the laser ECLIPSE at CEntre Lasers Intenses et Applications. In addition, IP sensitivity measurements were performed with a 160 kV X-ray generator at CEA DAM DIF, where the absolute response of IP SR and TR has been calibrated to X-rays in the energy range 8-75 keV with uncertainties of about 15%. Finally, the response functions have been modeled in Monte Carlo GEANT4 simulations in order to reproduce experimental data. Simulations enable extrapolation of the IP response functions to photon energies from 1 keV to 1 GeV, of interest, e.g., for laser-driven radiography.

  5. Validation of modelled imaging plates sensitivity to 1-100 keV x-rays and spatial resolution characterisation for diagnostics for the "PETawatt Aquitaine Laser".

    PubMed

    Boutoux, G; Batani, D; Burgy, F; Ducret, J-E; Forestier-Colleoni, P; Hulin, S; Rabhi, N; Duval, A; Lecherbourg, L; Reverdin, C; Jakubowska, K; Szabo, C I; Bastiani-Ceccotti, S; Consoli, F; Curcio, A; De Angelis, R; Ingenito, F; Baggio, J; Raffestin, D

    2016-04-01

    Thanks to their high dynamic range and ability to withstand electromagnetic pulse, imaging plates (IPs) are commonly used as passive detectors in laser-plasma experiments. In the framework of the development of the diagnostics for the Petawatt Aquitaine Laser facility, we present an absolute calibration and spatial resolution study of five different available types of IP (namely, MS-SR-TR-MP-ND) performed by using laser-induced K-shell X-rays emitted by a solid silver target irradiated by the laser ECLIPSE at CEntre Lasers Intenses et Applications. In addition, IP sensitivity measurements were performed with a 160 kV X-ray generator at CEA DAM DIF, where the absolute response of IP SR and TR has been calibrated to X-rays in the energy range 8-75 keV with uncertainties of about 15%. Finally, the response functions have been modeled in Monte Carlo GEANT4 simulations in order to reproduce experimental data. Simulations enable extrapolation of the IP response functions to photon energies from 1 keV to 1 GeV, of interest, e.g., for laser-driven radiography. PMID:27131655

  6. Electron-Heated Target Temperature Measurements in Petawatt Laser Experiments Based on Extreme Ultraviolet Imaging and Spectroscopy

    SciTech Connect

    Ma, T; Beg, F; Macphee, A; Chung, H; Key, M; Mackinnon, A; Patel, P; Hatchett, S; Akli, K; Stephens, R; Chen, C; Freeman, R; Link, A; Offermann, D; Ovchinnikov, V; VanWoerkom, L; Zhang, B

    2008-05-02

    Three independent methods (XUV spectroscopy, imaging at 68 eV and 256 eV) have been used to measure planar target rear surface plasma temperature due to heating by hot electrons. The hot electrons are produced by ultra-intense laser plasma interactions using the 150 J, 0.5 ps Titan laser. Soft x-ray spectroscopy in the 50-400 eV region and imaging at the 68 eV and 256 eV photon energies were used to determine the rear surface temperature of planar CD targets. Temperatures were found to be in the 60-150 eV range, with good agreement between the three diagnostics.

  7. Fast Ignition Realization Experiment with High-Contrast Kilo-Joule Peta-Watt Laser ``LFEX'' and Strong External Magnetic Field

    NASA Astrophysics Data System (ADS)

    Fujioka, Shinsuke

    2015-11-01

    We report on progresses of the Fast Ignition Realization Experiment (FIREX) project that has been curried out at the Institute of Laser Engineering to assess the feasibility of high density core heating with a high-power, short-pulse laser including the construction of the Kilo-Joule, Petawatt class LFEX laser system. Our recent studies identify three scientific challenges to achieve high heating efficiency in the fast ignition (FI) scheme with the current GEKKO and LFEX laser systems: (i) control of energy distribution of relativistic electron beam (REB), (ii) guiding and focusing of REB to a fuel core, and (iii) formation of a high areal-density core. The control of the electron energy distribution has been experimentally confirmed by improving the intensity contrast of the LFEX laser up to >109 and an ultra-high contrast of 1011 with a plasma mirror. After the contrast improvement, 50% of the total REB energy is carried by a low energy component of the REB, which slope temperature is close to the ponderomotive scaling value (~ 1 MeV). To guide the electron beam, we apply strong external magnetic field to the REB transport region. Guiding of the REB by 0.6 kT field in a planar geometry has already been demonstrated at LULI 2000 laser facility in a collaborative experiment lead by CELIA-Univ. Bordeaux. Considering more realistic FI scenario, we have performed a similar experiment using the Kilo-Joule LFEX laser to study the effect of guiding and magnetic mirror on the electron beam. A high density core of a laser-imploded 200 μm-diameter solid CD ball was radiographed with picosecond LFEX-produced K-alpha backlighter. Comparisons of the experimental results and integrated simulations using hydrodynamic and electron transport codes suggest that 10% of the efficiency can be achievable with the current GEKKO and LFEX laser system with the success of the above challenges. This work is supported by NIFS (Japan), MEXT/JSPS KAKENHI (Japan), JSPS Fellowship (Japan), ANR

  8. Petawatt Laser - Physics Today article

    SciTech Connect

    Perry, M.D.

    1997-07-02

    The development of small scale multiterawatt and now pentawatt lasers is described. The intent was to develop a laser capable of producing pentawatt pulses in order to examine the fast ignitor concept for inertial confinement fusion. This application requires high pulse energy in addition to the short pulse duration. The essential idea is to pre-implode a deuterium-tritium capsule to an isochoric condition.

  9. Neutron production by fast protons from ultraintense laser-plasma interactions

    SciTech Connect

    Yang, J.M.; McKenna, P.; Ledingham, K.W.D.; McCanny, T.; Robson, L.; Shimizu, S.; Singhal, R.P.; Wei, M.S.; Krushelnick, K.; Clarke, R.J.; Neely, D.; Norreys, P.A.

    2004-12-01

    Tens of MeV proton beams have been generated by interactions of the VULCAN petawatt laser with foil targets and used to induce nuclear reactions in zinc and boron samples. The numbers of {sup 11}C, {sup 66}Ga, {sup 67}Ga, {sup 68}Ga, {sup 61}Cu, {sup 62}Zn, {sup 63}Zn, and {sup 69m}Zn nuclei have been measured and used to determine the proton energy spectrum. It is known that (p,n) reactions provide an important method for producing neutron sources and in the present experiment up to {approx}10{sup 9} neutrons sr{sup -1} have been generated via {sup 11}B(p,n){sup 11}C reactions. Using experimentally determined proton energy spectra, the production of neutrons via (p,n) reactions in various targets has been simulated, to quantify neutron pulse intensities and energy spectra. It has been shown that as high as 4x10{sup 9} neutrons sr{sup -1} per laser pulse can be generated via {sup 7}Li(p,n){sup 7}B reactions using the present VULCAN petawatt laser-pulse conditions.

  10. Optimum laser intensity for the production of energetic deuterium ions from laser-cluster interaction

    NASA Astrophysics Data System (ADS)

    Bang, W.; Dyer, G.; Quevedo, H. J.; Bernstein, A. C.; Gaul, E.; Rougk, J.; Aymond, F.; Donovan, M. E.; Ditmire, T.

    2013-09-01

    We measured, using Petawatt-level pulses, the average ion energy and neutron yield in high-intensity laser interactions with molecular clusters as a function of laser intensity. The interaction volume over which fusion occurred (1-10 mm3) was larger than previous investigations, owing to the high laser power. Possible effects of prepulses were examined by implementing a pair of plasma mirrors. Our results show an optimum laser intensity for the production of energetic deuterium ions both with and without the use of the plasma mirrors. We measured deuterium plasmas with 14 keV average ion energies, which produced 7.2 × 106 and 1.6 × 107 neutrons in a single shot with and without plasma mirrors, respectively. The measured neutron yields qualitatively matched the expected yields calculated using a cylindrical plasma model.

  11. Optimum laser intensity for the production of energetic deuterium ions from laser-cluster interaction

    SciTech Connect

    Bang, W.; Dyer, G.; Quevedo, H. J.; Bernstein, A. C.; Gaul, E.; Rougk, J.; Aymond, F.; Donovan, M. E.; Ditmire, T.

    2013-09-15

    We measured, using Petawatt-level pulses, the average ion energy and neutron yield in high-intensity laser interactions with molecular clusters as a function of laser intensity. The interaction volume over which fusion occurred (1–10 mm{sup 3}) was larger than previous investigations, owing to the high laser power. Possible effects of prepulses were examined by implementing a pair of plasma mirrors. Our results show an optimum laser intensity for the production of energetic deuterium ions both with and without the use of the plasma mirrors. We measured deuterium plasmas with 14 keV average ion energies, which produced 7.2 × 10{sup 6} and 1.6 × 10{sup 7} neutrons in a single shot with and without plasma mirrors, respectively. The measured neutron yields qualitatively matched the expected yields calculated using a cylindrical plasma model.

  12. Laser-plasma interactions for fast ignition

    NASA Astrophysics Data System (ADS)

    Kemp, A. J.; Fiuza, F.; Debayle, A.; Johzaki, T.; Mori, W. B.; Patel, P. K.; Sentoku, Y.; Silva, L. O.

    2014-05-01

    In the electron-driven fast-ignition (FI) approach to inertial confinement fusion, petawatt laser pulses are required to generate MeV electrons that deposit several tens of kilojoules in the compressed core of an imploded DT shell. We review recent progress in the understanding of intense laser-plasma interactions (LPI) relevant to FI. Increases in computational and modelling capabilities, as well as algorithmic developments have led to enhancement in our ability to perform multi-dimensional particle-in-cell simulations of LPI at relevant scales. We discuss the physics of the interaction in terms of laser absorption fraction, the laser-generated electron spectra, divergence, and their temporal evolution. Scaling with irradiation conditions such as laser intensity are considered, as well as the dependence on plasma parameters. Different numerical modelling approaches and configurations are addressed, providing an overview of the modelling capabilities and limitations. In addition, we discuss the comparison of simulation results with experimental observables. In particular, we address the question of surrogacy of today's experiments for the full-scale FI problem.

  13. Laser–plasma interactions for fast ignition

    SciTech Connect

    Kemp, A. J.; Fiuza, F.; Debayle, A.; Johzaki, T.; Mori, W. B.; Patel, P. K.; Sentoku, Y.; Silva, L. O.

    2014-04-17

    In the electron-driven fast-ignition approach to inertial confinement fusion, petawatt laser pulses are required to generate MeV electrons that deposit several tens of kilojoules in the compressed core of an imploded DT shell. We review recent progress in the understanding of intense laser- plasma interactions (LPI) relevant to fast ignition. Increases in computational and modeling capabilities, as well as algorithmic developments have led to enhancement in our ability to perform multidimensional particle-in-cell (PIC) simulations of LPI at relevant scales. We discuss the physics of the interaction in terms of laser absorption fraction, the laser-generated electron spectra, divergence, and their temporal evolution. Scaling with irradiation conditions such as laser intensity, f-number and wavelength are considered, as well as the dependence on plasma parameters. Different numerical modeling approaches and configurations are addressed, providing an overview of the modeling capabilities and limitations. In addition, we discuss the comparison of simulation results with experimental observables. In particular, we address the question of surrogacy of today's experiments for the full-scale fast ignition problem.

  14. Laser–plasma interactions for fast ignition

    DOE PAGESBeta

    Kemp, A. J.; Fiuza, F.; Debayle, A.; Johzaki, T.; Mori, W. B.; Patel, P. K.; Sentoku, Y.; Silva, L. O.

    2014-04-17

    In the electron-driven fast-ignition approach to inertial confinement fusion, petawatt laser pulses are required to generate MeV electrons that deposit several tens of kilojoules in the compressed core of an imploded DT shell. We review recent progress in the understanding of intense laser- plasma interactions (LPI) relevant to fast ignition. Increases in computational and modeling capabilities, as well as algorithmic developments have led to enhancement in our ability to perform multidimensional particle-in-cell (PIC) simulations of LPI at relevant scales. We discuss the physics of the interaction in terms of laser absorption fraction, the laser-generated electron spectra, divergence, and their temporalmore » evolution. Scaling with irradiation conditions such as laser intensity, f-number and wavelength are considered, as well as the dependence on plasma parameters. Different numerical modeling approaches and configurations are addressed, providing an overview of the modeling capabilities and limitations. In addition, we discuss the comparison of simulation results with experimental observables. In particular, we address the question of surrogacy of today's experiments for the full-scale fast ignition problem.« less

  15. TOPICAL REVIEW: Relativistic laser-plasma interactions

    NASA Astrophysics Data System (ADS)

    Umstadter, Donald

    2003-04-01

    By focusing petawatt peak power laser light to intensities up to 1021 W cm-2, highly relativistic plasmas can now be studied. The force exerted by light pulses with this extreme intensity has been used to accelerate beams of electrons and protons to energies of a million volts in distances of only microns. This acceleration gradient is a thousand times greater than in radio-frequency-based accelerators. Such novel compact laser-based radiation sources have been demonstrated to have parameters that are useful for research in medicine, physics and engineering. They might also someday be used to ignite controlled thermonuclear fusion. Ultrashort pulse duration particles and x-rays that are produced can resolve chemical, biological or physical reactions on ultrafast (femtosecond) timescales and on atomic spatial scales. These energetic beams have produced an array of nuclear reactions, resulting in neutrons, positrons and radioactive isotopes. As laser intensities increase further and laser-accelerated protons become relativistic, exotic plasmas, such as dense electron-positron plasmas, which are of astrophysical interest, can be created in the laboratory. This paper reviews many of the recent advances in relativistic laser-plasma interactions.

  16. Dense electron-positron plasmas and gamma-ray bursts generation by counter-propagating quantum electrodynamics-strong laser interaction with solid targets

    SciTech Connect

    Luo, Wen; Zhu, Yi-Bo; Song, Ying-Ming; Zhu, Zhi-Chao; Wang, Xiao-Dong; Zhuo, Hong-Bin; Ma, Yan-Yun; Li, Xing-Huo; Turcu, I. C. E.; Chen, Min

    2015-06-15

    We use quantum electrodynamics (QED) particle-in-cell simulations to investigate and compare the generation of dense electron-positron plasmas and intense γ-ray bursts in the case of counter-propagating laser solid interaction (two-side irradiation) and single laser solid interaction (one-side irradiation). In the case of counter-propagating linearly polarized laser pulses irradiating a thin aluminum foil with each pulse peak power of 12.5 PW (I = 4 × 10{sup 23 }W/cm{sup 2}), we calculate that about 20% of the laser energy is converted into a burst of γ-rays with flux exceeding 10{sup 14 }s.{sup −1} This would be one of the most intense γ-ray sources among those currently available in laboratories. The γ-ray conversion efficiency in the case of two-side irradiation is three times higher than in the case of one-side irradiation using a single 12.5 PW laser. Dense electron-positron plasma with a maximum density of 6 × 10{sup 27 }m{sup −3} are generated simultaneously during the two-side irradiation which is eightfold denser compared to the one-side irradiation. The enhancement of the effects in the case of counter-propagating lasers are the results of the symmetrical compression of the foil target and the formation of electric potential and standing wave around the target. Realizing experimentally the proposed counter-propagating QED-strong laser-solid interaction to produce dense electron-positron pairs and prolific γ-rays will be made possible by the Extreme Light Infrastructure-Nuclear Physics facility under construction.

  17. A diagnostic for micrometer sensitive positioning of solid targets in intense laser-matter interaction

    NASA Astrophysics Data System (ADS)

    Singh, Prashant Kumar; Kakolee, K. F.; Jeong, T. W.; Ter-Avetisyan, Sargis

    2016-09-01

    A target position monitoring diagnostic, relevant to intense laser-solid interaction, is presented. The alignment system, having a sensitivity of few micrometers, consist of an infinity corrected long working distance objective, a broadband illuminating source and a CCD camera. The imaging system, placed along the axis of incident laser pulse, serves the dual purpose of laser focus diagnosis and precise positioning of the target in three dimension axis. By employing this technique, solid targets with thickness varying from opaque micrometer thick foils to few nanometer thin transparent foils can be aligned precisely. The effectiveness of the entire alignment system is demonstrated in enhanced acceleration of ions in intense laser-matter interaction, with very high reproducibility.

  18. Nonlinear interactions between electromagnetic waves and electron plasma oscillations in quantum plasmas.

    PubMed

    Shukla, P K; Eliasson, B

    2007-08-31

    We consider nonlinear interactions between intense circularly polarized electromagnetic (CPEM) waves and electron plasma oscillations (EPOs) in a dense quantum plasma, taking into account the electron density response in the presence of the relativistic ponderomotive force and mass increase in the CPEM wave fields. The dynamics of the CPEM waves and EPOs is governed by the two coupled nonlinear Schrödinger equations and Poisson's equation. The nonlinear equations admit the modulational instability of an intense CPEM pump wave against EPOs, leading to the formation and trapping of localized CPEM wave pipes in the electron density hole that is associated with a positive potential distribution in our dense plasma. The relevance of our investigation to the next generation intense laser-solid density plasma interaction experiments is discussed. PMID:17931024

  19. Nonlinear Interactions between Electromagnetic Waves and Electron Plasma Oscillations in Quantum Plasmas

    SciTech Connect

    Shukla, P. K.; Eliasson, B.

    2007-08-31

    We consider nonlinear interactions between intense circularly polarized electromagnetic (CPEM) waves and electron plasma oscillations (EPOs) in a dense quantum plasma, taking into account the electron density response in the presence of the relativistic ponderomotive force and mass increase in the CPEM wave fields. The dynamics of the CPEM waves and EPOs is governed by the two coupled nonlinear Schroedinger equations and Poisson's equation. The nonlinear equations admit the modulational instability of an intense CPEM pump wave against EPOs, leading to the formation and trapping of localized CPEM wave pipes in the electron density hole that is associated with a positive potential distribution in our dense plasma. The relevance of our investigation to the next generation intense laser-solid density plasma interaction experiments is discussed.

  20. Generation of high-quality petawatt pulses

    SciTech Connect

    Mourou, G; Bado, Philippe

    1991-01-01

    CPA sources need a front-end capable of generating very short seed pulses. To meet this requirement, present CPA sources rely on actively modelocked solid-state oscillators used in conjunction with non-linear fiber stages. This approach generates pulses with a residual frequency chirp, resulting in a limited peak-to-background intensity contrast ratio. The availability of an oscillator capable of producing directly (i.e. without fiber stage) picosecond or sub-picosecond pulses would significantly improve the quality of CPA sources. We have pursued different approaches to replace the standard modelocked oscillator front-end. In an initial phase, we investigated the possible use of Additive Pulse Modelocking (APM) color-center lasers as oscillators for CPA Nd:glass sources. Lately we have developed a Ti:Sapphire modelocked oscillator operating in the one-micron range. In order to generate pulses with very high peak to background contrast ratio, we have built a non-linear coupled-cavity oscillator generating 200-fs pulses. This color-center laser operates in the 1.5--1.6 micron range. A diagram of the oscillator is shown in Fig. 1. The laser is pumped with a modelocked Nd:YAG source. Both KCl and NaCl crystals were tested as gain media. NaCl was found to have a larger tuning range and to generate a higher average power (up to 150 mW). When synchronously mode-locked, the color-center generates pulses in the 10--20 ps range. Once interferometrically coupled to non-linear external-cavity, this oscillator produces very short pulses (85 to 260 fs). This oscillator was first operated with a 2 mm birefringent plate. 85 fs, near transform-limited pulses were generated at 1.54 micron. As the laser was tuned to longer wavelength, the pulse duration increased, as well as the bandwidth-duration product. With a 4 mm birefringent plate, 125 fs, transform-limited pulses were generated over the full tuning range.

  1. Laser-generated proton bunches from chirped laser-plasma interaction

    NASA Astrophysics Data System (ADS)

    Galow, Benjamin; Salamin, Yousef; Liseykina, Tatyana; Harman, Zoltan; Li, Jian-Xing; Keitel, Christoph

    2012-06-01

    Detailed single- and many-particle calculations are carried out for the acceleration of protons employing linearly-polarized plane-wave and tightly-focused chirped laser pulses of several ten to several hundred femtosecond durations, petawatt peak powers and relativistic peak intensities of the order of 10^21-10^22 W/cm^2 [1,2]. Analytic and numerical methods of calculation are used in the single-particle cases (in vacuum), and particle-in-cell (pic) simulations (under-dense plasma) are employed in the many-particle investigations, without and with electromagnetic particle-particle interactions, respectively. Feasibility of generating ultra-intense (10^7 particles per bunch) and phase-space collimated beams of protons is demonstrated. Interaction of the protons with the quasi-static part of the laser pulse allows the particles to gain sufficient kinetic energy (around 250 MeV) required for such applications as hadron cancer therapy.[4pt] [1] B. J. Galow, Y. I. Salamin, T. V. Liseykina, Z. Harman, and C. H. Keitel, Phys. Rev. Lett. 107, 185002 (2011)[0pt] [2] Y. I. Salamin, J.-X. Li, B. J. Galow, Z. Harman, and C. H. Keitel, submitted (2012)

  2. Measurement of electromagnetic pulses generated during interactions of high power lasers with solid targets

    NASA Astrophysics Data System (ADS)

    De Marco, M.; Krása, J.; Cikhardt, J.; Pfeifer, M.; Krouský, E.; Margarone, D.; Ahmed, H.; Borghesi, M.; Kar, S.; Giuffrida, L.; Vrana, R.; Velyhan, A.; Limpouch, J.; Korn, G.; Weber, S.; Velardi, L.; Delle Side, D.; Nassisi, V.; Ullschmied, J.

    2016-06-01

    A target irradiated with a high power laser pulse, blows off a large amount of charge and as a consequence the target itself becomes a generator of electromagnetic pulses (EMP) owing to high return current flowing to the ground through the target holder. The first measurement of the magnetic field induced by the neutralizing current reaching a value of a few kA was performed with the use of an inductive target probe at the PALS Laser Facility (Cikhardt et al. Rev. Sci. Instrum. 85 (2014) 103507). A full description of EMP generation should contain information on the spatial distribution and temporal variation of the electromagnetic field inside and outside of the interaction chamber. For this reason, we consider the interaction chamber as a resonant cavity in which different modes of EMP oscillate for hundreds of nanoseconds, until the EMP is transmitted outside through the glass windows and EM waves are attenuated. Since the experimental determination of the electromagnetic field distribution is limited by the number of employed antennas, a mapping of the electromagnetic field has to be integrated with numerical simulations. Thus, this work reports on a detailed numerical mapping of the electromagnetic field inside the interaction chamber at the PALS Laser Facility (covering a frequency spectrum from 100 MHz to 3 GHz) using the commercial code COMSOL Multiphysics 5.2. Moreover we carried out a comparison of the EMP generated in the parallelepiped-like interaction chamber used in the Vulcan Petawatt Laser Facility at the Rutherford Appleton Laboratory, against that produced in the spherical interaction chamber of PALS.

  3. An empirical model for the interaction of ultraintense laser pulses with fully ionized plasmas including electrostatic effects

    NASA Astrophysics Data System (ADS)

    Yang, Jeong-Hoon

    The fast ignitor approach to inertial confinement fusion offers an efficient route to produce higher energy gain for less driver energy and compressed fuel density than the conventional hydrodynamic ignition scheme. Over the last decade, serious efforts have been expended towards the goal of achieving controlled fusion using this new approach. However, until now no simple physical plasma model for this idea has been available and the feasibility of the fast ignition project by petawatt laser pulses is not yet clear. We have investigated the capability of ultrafast lasers with irradiance I > 1018 W cm-2 to produce highly energetic electron beams both in a planar wave and in a Gaussian focus in a low-density plasma and within a physical model of electrostatic effects in relativistic plasmas. The trajectory of a free electron in a plane wave with arbitrary initial conditions has been derived. From the complete solutions for the particle trajectory, we have also determined the initial velocities required to produce figure-of-eight motions for arbitrary initial particle positions. A new expression for the relativistic ponderomotive force has been developed. It compares very well with earlier work by Quesnel and Mora. The new expression promises to speed up particle-in-cell simulations. It has been found that free electrons escape from the Gaussian focal region of a 10-ps petawatt laser pulse very quickly before the field reaches its maximum amplitude. In this case very small net energy transfer occurs during the complete interaction of the electrons with the laser beam, indicating that (in the absence of collective electrostatic effects) free electrons cannot extract enough energy from the ignition laser pulse for ignition. This thesis presents a novel simulation model for predicting the large-scale dynamic behavior of the high intensity laser-plasma interaction. We have developed a simple particle simulation code to explore collective electrostatic effects in plasmas

  4. Integration of the Lorentz-Dirac equation: Interaction of an intense laser pulse with high-energy electrons.

    PubMed

    Koga, James

    2004-10-01

    Usually the motion of an electron under the influence of electromagnetic fields is influenced to a small extent by radiation damping. With the advent of high power high irradiance lasers it has become possible to generate focused laser irradiances where electrons interacting with the laser become highly relativistic over very short time and spatial scales. By focusing petawatt class lasers to very small spot sizes the amount of radiation emitted by electrons can become very large. Resultingly, the damping of the electron motion by the emission of this radiation can become large. In order to study this problem a code is written to solve a set of equations describing the evolution of a strong electromagnetic wave interacting with a single electron. Usually the equation of motion of an electron including radiation damping under the influence of electromagnetic fields is derived from the Lorentz-Dirac equation treating the damping as a perturbation. We use this equation to integrate forward in time and use the Lorentz-Dirac equation to integrate backward in time. We show that for very short wavelength electromagnetic radiation deep in the quantum regime at high irradiances differences between the perturbation equation and Lorentz-Dirac can be seen. However, for electron motion in the classical regime the differences are negligible. For electron motion in the classical regime the first order damping equation is found to be very adequate. PMID:15600540

  5. Powerful Interactions

    ERIC Educational Resources Information Center

    Dombro, Amy Laura; Jablon, Judy R.; Stetson, Charlotte

    2011-01-01

    Interactions are the daily exchanges in words and gestures one has with others. As a teacher, the interactions he/she has with young children can make a positive difference in their lives. A teacher's powerful interactions with children play an important role in their emotional well-being and learning. Powerful interactions are not the same as…

  6. Laser Ion Acceleration from the Interaction of Ultra-Intense laser Pulse with thi foils

    SciTech Connect

    Allen, M

    2004-03-12

    The discovery that ultra-intense laser pulses (I > 10{sup 18} W/cm{sup 2}) can produce short pulse, high energy proton beams has renewed interest in the fundamental mechanisms that govern particle acceleration from laser-solid interactions. Experiments have shown that protons present as hydrocarbon contaminants on laser targets can be accelerated up to energies > 50 MeV. Different theoretical models that explain the observed results have been proposed. One model describes a front-surface acceleration mechanism based on the ponderomotive potential of the laser pulse. At high intensities (I > 10{sup 18} W/cm{sup 2}), the quiver energy of an electron oscillating in the electric field of the laser pulse exceeds the electron rest mass, requiring the consideration of relativistic effects. The relativistically correct ponderomotive potential is given by U{sub p} = ([1 + I{lambda}{sup 2}/1.3 x 10{sup 18}]{sup 1/2} - 1) m{sub o}c{sup 2}, where I{lambda}{sup 2} is the irradiance in W{micro}m{sup 2}/cm{sup 2} and m{sub o}c{sup 2} is the electron rest mass.At laser irradiance of I{lambda}{sup 2} {approx} 10{sup 20} W{micro}m{sup 2}/cm{sup 2}, the ponderomotive potential can be of order several MeV. A few recent experiments--discussed in Chapter 3 of this thesis--consider this ponderomotive potential sufficiently strong to accelerate protons from the front surface of the target to energies up to tens of MeV. Another model, known as Target Normal Sheath Acceleration (TNSA), describes the mechanism as an electrostatic sheath on the back surface of the laser target. According to the TNSA model, relativistic hot electrons created at the laser-solid interaction penetrate the foil where a few escape to infinity. The remaining hot electrons are retained by the target potential and establish an electrostatic sheath on the back surface of the target.

  7. Drug Interactions

    PubMed Central

    Tong Logan, Angela; Silverman, Andrew

    2012-01-01

    One of the most clinically significant complications related to the use of pharmacotherapy is the potential for drug-drug or drug-disease interactions. The gastrointestinal system plays a large role in the pharmacokinetic profile of most medications, and many medications utilized in gastroenterology have clinically significant drug interactions. This review will discuss the impact of alterations of intestinal pH, interactions mediated by phase I hepatic metabolism enzymes and P-glycoprotein, the impact of liver disease on drug metabolism, and interactions seen with commonly utilized gastrointestinal medications. PMID:22933873

  8. Imagined Interactions

    ERIC Educational Resources Information Center

    Honeycutt, James M.

    2010-01-01

    Social scientists have been studying imagined interactions since the mid-1980s and have measured numerous physiological correlates (Honeycutt, 2010). In this commentary I assess the research reported in Crisp and Turner (May-June 2009) and highlight the underlying mechanisms of imagined interactions that have empirically been laid out across…

  9. Interacting parasites

    USGS Publications Warehouse

    Lafferty, Kevin D.

    2010-01-01

    Parasitism is the most popular life-style on Earth, and many vertebrates host more than one kind of parasite at a time. A common assumption is that parasite species rarely interact, because they often exploit different tissues in a host, and this use of discrete resources limits competition (1). On page 243 of this issue, however, Telfer et al. (2) provide a convincing case of a highly interactive parasite community in voles, and show how infection with one parasite can affect susceptibility to others. If some human parasites are equally interactive, our current, disease-by-disease approach to modeling and treating infectious diseases is inadequate (3).

  10. Drug Interactions

    MedlinePlus

    ... not be taken at the same time as antacids. WHAT CAUSES THE MOST INTERACTIONS WITH HIV MEDICATIONS? ... azole” Some antibiotics (names end in “mycin”) The antacid cimetidine (Tagamet) Some drugs that prevent convulsions, including ...

  11. Magnetic collimation of relativistic positrons and electrons from high intensity laser–matter interactions

    SciTech Connect

    Chen, Hui; Heeter, R. F.; Link, A.; Fiksel, G.; Barnak, D.; Chang, P.-Y.; Meyerhofer, D. D.

    2014-04-15

    Collimation of positrons produced by laser-solid interactions has been observed using an externally applied axial magnetic field. The collimation leads to a narrow divergence positron beam, with an equivalent full width at half maximum beam divergence angle of 4° vs the un-collimated divergence of about 20°. A fraction of the laser-produced relativistic electrons with energies close to those of the positrons is collimated, so the charge imbalance ratio (n{sub e−}/n{sub e+}) in the co-propagating collimated electron-positron jet is reduced from ∼100 (no collimation) to ∼2.5 (with collimation). The positron density in the collimated beam increased from 5 × 10{sup 7} cm{sup −3} to 1.9 × 10{sup 9} cm{sup −3}, measured at the 0.6 m from the source. This is a significant step towards the grand challenge of making a charge neutral electron-positron pair plasma jet in the laboratory.

  12. Parametric study of transport beam lines for electron beams accelerated by laser-plasma interaction

    NASA Astrophysics Data System (ADS)

    Scisciò, M.; Lancia, L.; Migliorati, M.; Mostacci, A.; Palumbo, L.; Papaphilippou, Y.; Antici, P.

    2016-03-01

    In the last decade, laser-plasma acceleration of high-energy electrons has attracted strong attention in different fields. Electrons with maximum energies in the GeV range can be laser-accelerated within a few cm using multi-hundreds terawatt (TW) lasers, yielding to very high beam currents at the source (electron bunches with up to tens-hundreds of pC in a few fs). While initially the challenge was to increase the maximum achievable electron energy, today strong effort is put in the control and usability of these laser-generated beams that still lack of some features in order to be used for applications where currently conventional, radio-frequency (RF) based, electron beam lines represent the most common and efficient solution. Several improvements have been suggested for this purpose, some of them acting directly on the plasma source, some using beam shaping tools located downstream. Concerning the latter, several studies have suggested the use of conventional accelerator magnetic devices (such as quadrupoles and solenoids) as an easy implementable solution when the laser-plasma accelerated beam requires optimization. In this paper, we report on a parametric study related to the transport of electron beams accelerated by laser-plasma interaction, using conventional accelerator elements and tools. We focus on both, high energy electron beams in the GeV range, as produced on petawatt (PW) class laser systems, and on lower energy electron beams in the hundreds of MeV range, as nowadays routinely obtained on commercially available multi-hundred TW laser systems. For both scenarios, our study allows understanding what are the crucial parameters that enable laser-plasma accelerators to compete with conventional ones and allow for a beam transport. We show that suitable working points require a tradeoff-combination between low beam divergence and narrow energy spread.

  13. Advanced Compressor Designs for High Energy Petawatt Pulse Generation

    SciTech Connect

    Fittinghoff, D N; Wattellier, B; Barty, C P J

    2003-09-09

    We discuss compressor designs for a proposed multikilojoule, sub-picosecond beamline at the National Ignition Facility. A novel grating configuration reduces the size of the compressor chamber. Optimization of the design leads to a 4.7 x 1.4 x 0.4 m{sup 3} minimum compressor volume.

  14. SPECTRAL AMPLITUDE AND PHASE EVOLUTION IN PETAWATT LASER PULSES

    SciTech Connect

    Filip, C V

    2010-11-22

    The influence of the active gain medium on the spectral amplitude and phase of amplified pulses in a CPA system is studied. Results from a 10-PW example based on Nd-doped mixed glasses are presented. In conclusion, this study shows that, by using spectral shaping and gain saturation in a mixed-glass amplifier, it is possible to produce 124 fs, 1.4 kJ laser pulses. One detrimental effect, the pulse distortion due to resonant amplification medium, has been investigated and its magnitude as well as its compensation calculated.

  15. Strong Interaction

    SciTech Connect

    Karsch, F.; Vogelsang, V.

    2009-09-29

    We will give here an overview of our theory of the strong interactions, Quantum Chromo Dynamics (QCD) and its properties. We will also briefly review the history of the study of the strong interactions, and the discoveries that ultimately led to the formulation of QCD. The strong force is one of the four known fundamental forces in nature, the others being the electromagnetic, the weak and the gravitational force. The strong force, usually referred to by scientists as the 'strong interaction', is relevant at the subatomic level, where it is responsible for the binding of protons and neutrons to atomic nuclei. To do this, it must overcome the electric repulsion between the protons in an atomic nucleus and be the most powerful force over distances of a few fm (1fm=1 femtometer=1 fermi=10{sup -15}m), the typical size of a nucleus. This property gave the strong force its name.

  16. A study of fast electron energy transport in relativistically intense laser-plasma interactions with large density scalelengths

    SciTech Connect

    Scott, R. H. H.; Norreys, P. A.; Perez, F.; Baton, S. D.; Davies, J. R.; Lancaster, K. L.; Trines, R. M. G. M.; Bell, A. R.; Tzoufras, M.; Rose, S. J.

    2012-05-15

    A systematic experimental and computational investigation of the effects of three well characterized density scalelengths on fast electron energy transport in ultra-intense laser-solid interactions has been performed. Experimental evidence is presented which shows that, when the density scalelength is sufficiently large, the fast electron beam entering the solid-density plasma is best described by two distinct populations: those accelerated within the coronal plasma (the fast electron pre-beam) and those accelerated near or at the critical density surface (the fast electron main-beam). The former has considerably lower divergence and higher temperature than that of the main-beam with a half-angle of {approx}20 Degree-Sign . It contains up to 30% of the total fast electron energy absorbed into the target. The number, kinetic energy, and total energy of the fast electrons in the pre-beam are increased by an increase in density scalelength. With larger density scalelengths, the fast electrons heat a smaller cross sectional area of the target, causing the thinnest targets to reach significantly higher rear surface temperatures. Modelling indicates that the enhanced fast electron pre-beam associated with the large density scalelength interaction generates a magnetic field within the target of sufficient magnitude to partially collimate the subsequent, more divergent, fast electron main-beam.

  17. Weak Interactions

    DOE R&D Accomplishments Database

    Lee, T. D.

    1957-06-01

    Experimental results on the non-conservation of parity and charge conservation in weak interactions are reviewed. The two-component theory of the neutrino is discussed. Lepton reactions are examined under the assumption of the law of conservation of leptons and that the neutrino is described by a two- component theory. From the results of this examination, the universal Fermi interactions are analyzed. Although reactions involving the neutrino can be described, the same is not true of reactions which do not involve the lepton, as the discussion of the decay of K mesons and hyperons shows. The question of the invariance of time reversal is next examined. (J.S.R.)

  18. Ultrabroadband Relay Imaged GRENOUILLE as a Time-Resolved Diagnostic for Relativistic Hole Boring

    NASA Astrophysics Data System (ADS)

    Wagner, Craig; Bernstein, Aaron; Dyer, Gilliss; Ditmire, Todd

    2015-11-01

    In a highly intense laser-solid interaction, the surface of the resultant plasma is pushed into the interior of the target at a significant fraction of the speed of light as a result of the intense radiation pressure from the focused laser beam. This is known as hole boring. During the hole boring process laser interactions with electrons at the receding target surface generate light at frequency harmonics of the incident laser. The frequency shift of these harmonics is proportional to the velocity of the target surface. In previous experiments at the Texas Petawatt we observed red-shifts in the 351nm harmonic up to 513nm, corresponding to a recession velocity of 0.18c. We designed an ultra-broadband GRENOUILLE to conduct time resolved measurements of spectral shifting of second harmonic light over the duration of the incident laser pulse. This GRENOUILLE is relay imaged from the target plane to prevent spectral splitting, and is an all reflective design to reduce pulse broadening and chromatic aberrations. With an f/3.15 optic focusing into a thick BBO crystal, the system accepts wavelengths from 526nm to 766nm with 4.8nm spectral resolution and 5.6fs temporal resolution. This work was supported by NNSA cooperative agreement DE-NA0002008.

  19. Interactive Video.

    ERIC Educational Resources Information Center

    Boyce, Carol

    1992-01-01

    A workshop on interactive video was designed for fourth and fifth grade students, with the goals of familiarizing students with laser disc technology, developing a cadre of trained students to train other students and staff, and challenging able learners to utilize higher level thinking skills while conducting a research project. (JDD)

  20. Interacting Compasses

    ERIC Educational Resources Information Center

    Riveros, Hector G.; Betancourt, Julian

    2009-01-01

    The use of multiple compasses to map and visualize magnetic fields is well-known. The magnetic field exerts a torque on the compasses aligning them along the lines of force. Some science museums show the field of a magnet using a table with many compasses in a closely packed arrangement. However, the very interesting interactions that occur…

  1. Interactive Astronomy.

    ERIC Educational Resources Information Center

    Martin, Jean K.

    1997-01-01

    Presents guiding principles for developing interactive lessons for the World Wide Web. Describes "Amazing Space: Education Online from the Hubble Space Telescope", a program where students study spectacular Hubble Space Telescope images of stars and star-forming regions to learn about the life cycle of stars and the creation of atoms. (JRH)

  2. Putting Interaction into Interactive Television.

    ERIC Educational Resources Information Center

    Wolfe, Thomas E.

    Current technology provides many new ideas and alternatives to traditional education and training practices. From the experience of the U.S. Air Force (USAF) Academic Instructor School (AIS) and current research in the field, teaching via interactive television (teleseminar/video teletraining) requires new teaching skills and new ways of thinking…

  3. Argentophilic interactions.

    PubMed

    Schmidbaur, Hubert; Schier, Annette

    2015-01-12

    The decade 1990-2000 saw a growing interest in aurophilic interactions in gold chemistry. These interactions were found to influence significantly a variety of structural and other physical characteristics of gold(I) compounds. The attention paid to this unusual and counterintuitive type of intra- and intermolecular bonding between seemingly closed-shell metal centers has rapidly been extended to also include silver chemistry. Hundreds of experimental and computational studies have since been dedicated to the argentophilicity phenomenon. The results of this development are reviewed herein focusing on molecular systems where two or more silver(I) centers are in close contact leading to specific structural characteristics and a variety of novel physical properties. These include strongly modified ligand-to-metal charge-transfer processes observed in absorption and emission spectroscopy, but also colossal positive and negative thermal expansion on the one hand and unprecedented negative linear compressibility of crystal parameters on the other. PMID:25393553

  4. Electroweak interactions

    SciTech Connect

    Renton, P.

    1990-01-01

    The central part of the book consists of a comprehensive discussion of many scattering and decay processes involving electromagnetic, weak and strong interactions. A list of topics includes electron-proton scattering, Compton scattering, muon decay, electron-positron annihilation, photon and hadron structure functions, neutrino-nucleus scattering, Cabibbo theory, tau-lepton decays, W and Z boson decays, mixing phenomena and many others. For most processes, the author presents the appropriate Feynman diagrams, first-order matrix elements and the resulting cross sections or decay rates. The last section of Electroweak Interactions discusses some of the open or unanswered questions in the standard model, including the undiscovered top quark, the Higgs mechanism of electroweak symmetry breaking and detailed tests involving radiative effects. The book concludes with a brief account of ideas that extend beyond the standard model, such as left-right symmetric models, grand unified theories, compositeness, supersymmetry and string theory.

  5. Cosmic Interactions

    NASA Astrophysics Data System (ADS)

    2008-01-01

    An image based on data taken with ESO's Very Large Telescope reveals a triplet of galaxies intertwined in a cosmic dance. ESO PR Photo 02/08 ESO PR Photo 02/08 NGC 7173, 7174, and 7176 The three galaxies, catalogued as NGC 7173 (top), 7174 (bottom right) and 7176 (bottom left), are located 106 million light-years away towards the constellation of Piscis Austrinus (the 'Southern Fish'). NGC 7173 and 7176 are elliptical galaxies, while NGC 7174 is a spiral galaxy with quite disturbed dust lanes and a long, twisted tail. This seems to indicate that the two bottom galaxies - whose combined shape bears some resemblance to that of a sleeping baby - are currently interacting, with NGC 7176 providing fresh material to NGC 7174. Matter present in great quantity around the triplet's members also points to the fact that NGC 7176 and NGC 7173 have interacted in the past. Astronomers have suggested that the three galaxies will finally merge into a giant 'island universe', tens to hundreds of times as massive as our own Milky Way. ESO PR Photo 02/08 ESO PR Photo 02b/08 NGC 7173, 7174, and 7176 The triplet is part of a so-called 'Compact Group', as compiled by Canadian astronomer Paul Hickson in the early 1980s. The group, which is the 90th entry in the catalogue and is therefore known as HCG 90, actually contains four major members. One of them - NGC 7192 - lies above the trio, outside of this image, and is another peculiar spiral galaxy. Compact groups are small, relatively isolated, systems of typically four to ten galaxies in close proximity to one another. Another striking example is Robert's Quartet. Compact groups are excellent laboratories for the study of galaxy interactions and their effects, in particular the formation of stars. As the striking image reveals, there are many other galaxies in the field. Some are distant ones, while others seem to be part of the family. Studies made with other telescopes have indeed revealed that the HCG 90 group contains 16 members

  6. Designing "Interaction": How Do Interaction Design Students Address Interaction?

    ERIC Educational Resources Information Center

    Karlgren, Klas; Ramberg, Robert; Artman, Henrik

    2016-01-01

    Interaction design is usually described as being concerned with interactions with and through artifacts but independent of a specific implementation. Design work has been characterized as a conversation between the designer and the situation and this conversation poses a particular challenge for interaction design as interactions can be elusive…

  7. Cloud Interactions

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 1 July 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth.

    Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms.

    This image was acquired during mid-spring near the North Pole. The linear water-ice clouds are now regional in extent and often interact with neighboring cloud system, as seen in this image. The bottom of the image shows how the interaction can destroy the linear nature. While the surface is still visible through most of the clouds, there is evidence that dust is also starting to enter the atmosphere.

    Image information: VIS instrument. Latitude 68.4, Longitude 258.8 East (101.2 West). 38 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration

  8. Electron dynamics controlled via self-interaction.

    PubMed

    Tamburini, Matteo; Keitel, Christoph H; Di Piazza, Antonino

    2014-02-01

    The dynamics of an electron in a strong laser field can be significantly altered by radiation reaction. This usually results in a strongly damped motion, with the electron losing a large fraction of its initial energy. Here we show that the electron dynamics in a bichromatic laser pulse can be indirectly controlled by a comparatively small radiation reaction force through its interplay with the Lorentz force. By changing the relative phase between the two frequency components of the bichromatic laser field, an ultrarelativistic electron bunch colliding head-on with the laser pulse can be deflected in a controlled way, with the deflection angle being independent of the initial electron energy. The effect is predicted to be observable with laser powers and intensities close to those of current state-of-the-art petawatt laser systems. PMID:25353414

  9. Colloquium: Nonlinear collective interactions in quantum plasmas with degenerate electron fluids

    SciTech Connect

    Shukla, P. K.; Eliasson, B.

    2011-07-01

    The current understanding of some important nonlinear collective processes in quantum plasmas with degenerate electrons is presented. After reviewing the basic properties of quantum plasmas, model equations (e.g., the quantum hydrodynamic and effective nonlinear Schroedinger-Poisson equations) are presented that describe collective nonlinear phenomena at nanoscales. The effects of the electron degeneracy arise due to Heisenberg's uncertainty principle and Pauli's exclusion principle for overlapping electron wave functions that result in tunneling of electrons and the electron degeneracy pressure. Since electrons are Fermions (spin-1/2 quantum particles), there also appears an electron spin current and a spin force acting on electrons due to the Bohr magnetization. The quantum effects produce new aspects of electrostatic (ES) and electromagnetic (EM) waves in a quantum plasma that are summarized in here. Furthermore, nonlinear features of ES ion waves and electron plasma oscillations are discussed, as well as the trapping of intense EM waves in quantum electron-density cavities. Specifically, simulation studies of the coupled nonlinear Schroedinger and Poisson equations reveal the formation and dynamics of localized ES structures at nanoscales in a quantum plasma. The effect of an external magnetic field on the plasma wave spectra and develop quantum magnetohydrodynamic equations are also discussed. The results are useful for understanding numerous collective phenomena in quantum plasmas, such as those in compact astrophysical objects (e.g., the cores of white dwarf stars and giant planets), as well as in plasma-assisted nanotechnology (e.g., quantum diodes, quantum free-electron lasers, nanophotonics and nanoplasmonics, metallic nanostructures, thin metal films, semiconductor quantum wells, and quantum dots, etc.), and in the next generation of intense laser-solid density plasma interaction experiments relevant for fast ignition in inertial confinement fusion

  10. PIC: Protein Interactions Calculator.

    PubMed

    Tina, K G; Bhadra, R; Srinivasan, N

    2007-07-01

    Interactions within a protein structure and interactions between proteins in an assembly are essential considerations in understanding molecular basis of stability and functions of proteins and their complexes. There are several weak and strong interactions that render stability to a protein structure or an assembly. Protein Interactions Calculator (PIC) is a server which, given the coordinate set of 3D structure of a protein or an assembly, computes various interactions such as disulphide bonds, interactions between hydrophobic residues, ionic interactions, hydrogen bonds, aromatic-aromatic interactions, aromatic-sulphur interactions and cation-pi interactions within a protein or between proteins in a complex. Interactions are calculated on the basis of standard, published criteria. The identified interactions between residues can be visualized using a RasMol and Jmol interface. The advantage with PIC server is the easy availability of inter-residue interaction calculations in a single site. It also determines the accessible surface area and residue-depth, which is the distance of a residue from the surface of the protein. User can also recognize specific kind of interactions, such as apolar-apolar residue interactions or ionic interactions, that are formed between buried or exposed residues or near the surface or deep inside. PMID:17584791

  11. Interacting dark sector with transversal interaction

    SciTech Connect

    Chimento, Luis P.; Richarte, Martín G.

    2015-03-26

    We investigate the interacting dark sector composed of dark matter, dark energy, and dark radiation for a spatially flat Friedmann-Robertson-Walker (FRW) background by introducing a three-dimensional internal space spanned by the interaction vector Q and solve the source equation for a linear transversal interaction. Then, we explore a realistic model with dark matter coupled to a scalar field plus a decoupled radiation term, analyze the amount of dark energy in the radiation era and find that our model is consistent with the recent measurements of cosmic microwave background anisotropy coming from Planck along with the future constraints achievable by CMBPol experiment.

  12. Interactivity: A Forgotten Art?

    ERIC Educational Resources Information Center

    Sims, Rod

    1997-01-01

    This paper promotes further discussion and analysis of interactivity in learning environments and contains a classification of interaction types appropriate for consideration in multimedia settings. Through an examination of related factors associated with navigation and control, a matrix of interactive dimensions is proposed. (Author)

  13. Global Interaction in Design

    ERIC Educational Resources Information Center

    Bennett, Audrey Grace

    2010-01-01

    Based on a virtual conference, Glide'08 (Global Interaction in Design Education), that brought international design scholars together online, this special issue expands on the topics of cross-cultural communication and design and the technological affordances that support such interaction. The author discusses the need for global interaction in…

  14. Evolving synergetic interactions

    PubMed Central

    Wu, Bin; Arranz, Jordi; Du, Jinming; Zhou, Da; Traulsen, Arne

    2016-01-01

    Cooperators forgo their own interests to benefit others. This reduces their fitness and thus cooperators are not likely to spread based on natural selection. Nonetheless, cooperation is widespread on every level of biological organization ranging from bacterial communities to human society. Mathematical models can help to explain under which circumstances cooperation evolves. Evolutionary game theory is a powerful mathematical tool to depict the interactions between cooperators and defectors. Classical models typically involve either pairwise interactions between individuals or a linear superposition of these interactions. For interactions within groups, however, synergetic effects may arise: their outcome is not just the sum of its parts. This is because the payoffs via a single group interaction can be different from the sum of any collection of two-player interactions. Assuming that all interactions start from pairs, how can such synergetic multiplayer games emerge from simpler pairwise interactions? Here, we present a mathematical model that captures the transition from pairwise interactions to synergetic multiplayer ones. We assume that different social groups have different breaking rates. We show that non-uniform breaking rates do foster the emergence of synergy, even though individuals always interact in pairs. Our work sheds new light on the mechanisms underlying such synergetic interactions. PMID:27466437

  15. Evolving synergetic interactions.

    PubMed

    Wu, Bin; Arranz, Jordi; Du, Jinming; Zhou, Da; Traulsen, Arne

    2016-07-01

    Cooperators forgo their own interests to benefit others. This reduces their fitness and thus cooperators are not likely to spread based on natural selection. Nonetheless, cooperation is widespread on every level of biological organization ranging from bacterial communities to human society. Mathematical models can help to explain under which circumstances cooperation evolves. Evolutionary game theory is a powerful mathematical tool to depict the interactions between cooperators and defectors. Classical models typically involve either pairwise interactions between individuals or a linear superposition of these interactions. For interactions within groups, however, synergetic effects may arise: their outcome is not just the sum of its parts. This is because the payoffs via a single group interaction can be different from the sum of any collection of two-player interactions. Assuming that all interactions start from pairs, how can such synergetic multiplayer games emerge from simpler pairwise interactions? Here, we present a mathematical model that captures the transition from pairwise interactions to synergetic multiplayer ones. We assume that different social groups have different breaking rates. We show that non-uniform breaking rates do foster the emergence of synergy, even though individuals always interact in pairs. Our work sheds new light on the mechanisms underlying such synergetic interactions. PMID:27466437

  16. Convergence in Multispecies Interactions.

    PubMed

    Bittleston, Leonora S; Pierce, Naomi E; Ellison, Aaron M; Pringle, Anne

    2016-04-01

    The concepts of convergent evolution and community convergence highlight how selective pressures can shape unrelated organisms or communities in similar ways. We propose a related concept, convergent interactions, to describe the independent evolution of multispecies interactions with similar physiological or ecological functions. A focus on convergent interactions clarifies how natural selection repeatedly favors particular kinds of associations among species. Characterizing convergent interactions in a comparative context is likely to facilitate prediction of the ecological roles of organisms (including microbes) in multispecies interactions and selective pressures acting in poorly understood or newly discovered multispecies systems. We illustrate the concept of convergent interactions with examples: vertebrates and their gut bacteria; ectomycorrhizae; insect-fungal-bacterial interactions; pitcher-plant food webs; and ants and ant-plants. PMID:26858111

  17. The Interactive Learning Toolkit: supporting interactive classrooms

    NASA Astrophysics Data System (ADS)

    Dutta, S.; McCauley, V.; Mazur, E.

    2004-05-01

    Research-based interactive learning techniques have dramatically improved student understanding. We have created the 'Interactive Learning Toolkit' (ILT), a web-based learning management system, to help implement two such pedagogies: Just in Time Teaching and Peer Instruction. Our main goal in developing this toolkit is to save the instructor time and effort and to use technology to facilitate the interaction between the students and the instructor (and between students themselves). After a brief review of both pedagogies, we will demonstrate the many exciting new features of the ILT. We will show how technology can not only implement, but also supplement and improve these pedagogies. We would like acknowdge grants from NSF and DEAS, Harvard University

  18. Antiplatelet drug interactions.

    PubMed

    Mackenzie, I S; Coughtrie, M W H; MacDonald, T M; Wei, L

    2010-12-01

    Both laboratory studies in healthy volunteers and clinical studies have suggested adverse interactions between antiplatelet drugs and other commonly used medications. Interactions described include those between aspirin and ibuprofen, aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), and the thienopyridine, clopidogrel, and drugs inhibiting CYP2C19, notably the proton pump inhibitors (PPI) omeprazole and esomeprazole. Other interactions between thienopyridines and CYP3A4/5 have also been reported for statins and calcium channel blockers. The ibuprofen/aspirin interaction is thought to be caused by ibuprofen blocking the access of aspirin to platelet cyclo-oxygenase. The thienopyridine interactions are caused by inhibition of microsomal enzymes that metabolize these pro-drugs to their active metabolites. We review the evidence for these interactions, assess their clinical importance and suggest strategies of how to deal with them in clinical practice. We conclude that ibuprofen is likely to interact with aspirin and reduce its anti-platelet action particularly in those patients who take ibuprofen chronically. This interaction is of greater relevance to those patients at high cardiovascular risk. A sensible strategy is to advise users of aspirin to avoid chronic ibuprofen or to ingest aspirin at least 2 h prior to ibuprofen. Clearly the use of NSAIDs that do not interact in this way is preferred. For the clopidogrel CYP2C19 and CYP3A4/5 interactions, there is good evidence that these interactions occur. However, there is less good evidence to support the clinical importance of these interactions. Again, a reasonable strategy is to avoid the chronic use of drugs that inhibit CYP2C19, notably PPIs, in subjects taking clopidogrel and use high dose H2 antagonists instead. Finally, anti-platelet agents probably interact with other drugs that affect platelet function such as selective serotonin reuptake inhibitors, and clinicians should probably judge

  19. The interactive brain hypothesis

    PubMed Central

    Di Paolo, Ezequiel; De Jaegher, Hanne

    2012-01-01

    Enactive approaches foreground the role of interpersonal interaction in explanations of social understanding. This motivates, in combination with a recent interest in neuroscientific studies involving actual interactions, the question of how interactive processes relate to neural mechanisms involved in social understanding. We introduce the Interactive Brain Hypothesis (IBH) in order to help map the spectrum of possible relations between social interaction and neural processes. The hypothesis states that interactive experience and skills play enabling roles in both the development and current function of social brain mechanisms, even in cases where social understanding happens in the absence of immediate interaction. We examine the plausibility of this hypothesis against developmental and neurobiological evidence and contrast it with the widespread assumption that mindreading is crucial to all social cognition. We describe the elements of social interaction that bear most directly on this hypothesis and discuss the empirical possibilities open to social neuroscience. We propose that the link between coordination dynamics and social understanding can be best grasped by studying transitions between states of coordination. These transitions form part of the self-organization of interaction processes that characterize the dynamics of social engagement. The patterns and synergies of this self-organization help explain how individuals understand each other. Various possibilities for role-taking emerge during interaction, determining a spectrum of participation. This view contrasts sharply with the observational stance that has guided research in social neuroscience until recently. We also introduce the concept of readiness to interact to describe the practices and dispositions that are summoned in situations of social significance (even if not interactive). This latter idea links interactive factors to more classical observational scenarios. PMID:22701412

  20. Food-Drug Interactions

    PubMed Central

    Bushra, Rabia; Aslam, Nousheen; Khan, Arshad Yar

    2011-01-01

    The effect of drug on a person may be different than expected because that drug interacts with another drug the person is taking (drug-drug interaction), food, beverages, dietary supplements the person is consuming (drug-nutrient/food interaction) or another disease the person has (drug-disease interaction). A drug interaction is a situation in which a substance affects the activity of a drug, i.e. the effects are increased or decreased, or they produce a new effect that neither produces on its own. These interactions may occur out of accidental misuse or due to lack of knowledge about the active ingredients involved in the relevant substances. Regarding food-drug interactions physicians and pharmacists recognize that some foods and drugs, when taken simultaneously, can alter the body's ability to utilize a particular food or drug, or cause serious side effects. Clinically significant drug interactions, which pose potential harm to the patient, may result from changes in pharmaceutical, pharmacokinetic, or pharmacodynamic properties. Some may be taken advantage of, to the benefit of patients, but more commonly drug interactions result in adverse drug events. Therefore it is advisable for patients to follow the physician and doctors instructions to obtain maximum benefits with least food-drug interactions. The literature survey was conducted by extracting data from different review and original articles on general or specific drug interactions with food. This review gives information about various interactions between different foods and drugs and will help physicians and pharmacists prescribe drugs cautiously with only suitable food supplement to get maximum benefit for the patient. PMID:22043389

  1. Beam-Bem interactions

    SciTech Connect

    Kim, Hyung Jin; /Fermilab

    2011-12-01

    In high energy storage-ring colliders, the nonlinear effect arising from beam-beam interactions is a major source that leads to the emittance growth, the reduction of beam life time, and limits the collider luminosity. In this paper, two models of beam-beam interactions are introduced, which are weak-strong and strong-strong beam-beam interactions. In addition, space-charge model is introduced.

  2. Interactive brains, social minds

    PubMed Central

    Lindenberger, Ulman

    2011-01-01

    To reveal the neural and behavioral dynamics of social interaction, single-person studies are increasingly complemented by research designs that simultaneously assess two or more interacting individuals. In this article, we review studies on neural mechanisms and markers of social interactions that use multi-person functional magnetic resonance imaging and electrophysiological recordings. We propose a terminology for investigating social interaction dynamics, show how forward models of action regulation may serve as a framework for investigating interpersonal action coordination and discuss different methodological approaches to studying functional brain connectivity. PMID:22448303

  3. Nerve-pulse interactions

    SciTech Connect

    Scott, A.C.

    1982-01-01

    Some recent experimental and theoretical results on mechanisms through which individual nerve pulses can interact are reviewed. Three modes of interactions are considered: (1) interaction of pulses as they travel along a single fiber which leads to velocity dispersion; (2) propagation of pairs of pulses through a branching region leading to quantum pulse code transformations; and (3) interaction of pulses on parallel fibers through which they may form a pulse assembly. This notion is analogous to Hebb's concept of a cell assembly, but on a lower level of the neural hierarchy.

  4. Interactive brains, social minds.

    PubMed

    Sänger, Johanna; Lindenberger, Ulman; Müller, Viktor

    2011-11-01

    To reveal the neural and behavioral dynamics of social interaction, single-person studies are increasingly complemented by research designs that simultaneously assess two or more interacting individuals. In this article, we review studies on neural mechanisms and markers of social interactions that use multi-person functional magnetic resonance imaging and electrophysiological recordings. We propose a terminology for investigating social interaction dynamics, show how forward models of action regulation may serve as a framework for investigating interpersonal action coordination and discuss different methodological approaches to studying functional brain connectivity. PMID:22448303

  5. Two interacting Hofstadter butterflies

    SciTech Connect

    Barelli, A.; Bellissard, J.; Jacquod, P.; Shepelyansky, D.L.

    1997-04-01

    The problem of two interacting particles in a quasiperiodic potential is addressed. Using analytical and numerical methods, we explore the spectral properties and eigenstates structure from the weak to the strong interaction case. More precisely, a semiclassical approach based on noncommutative geometry techniques is used to understand the intricate structure of such a spectrum. An interaction induced localization effect is furthermore emphasized. We discuss the application of our results on a two-dimensional model of two particles in a uniform magnetic field with on-site interaction. {copyright} {ital 1997} {ital The American Physical Society}

  6. The Science of Interaction

    SciTech Connect

    Pike, William A.; Stasko, John T.; Chang, Remco; O'Connell, Theresa

    2009-09-23

    There is a growing recognition with the visual analytics community that interaction and inquiry are inextricable. It is through the interactive manipulation of a visual interface – the analytic discourse – that knowledge is constructed, tested, refined, and shared. This paper reflects on the interaction challenges raised in the original visual analytics research and development agenda and further explores the relationship between interaction and cognition. It identifies recent exemplars of visual analytics research that have made substantive progress toward the goals of a true science of interaction, which must include theories and testable premises about the most appropriate mechanisms for human-information interaction. Six areas for further work are highlighted as those among the highest priorities for the next five years of visual analytics research: ubiquitous, embodied interaction; capturing user intentionality; knowledge-based interfaces; principles of design and perception; collaboration; and interoperability. Ultimately, the goal of a science of interaction is to support the visual analytics community through the recognition and implementation of best practices in the representation of and interaction with visual displays.

  7. Reconceptualizing sex, brain and psychopathology: interaction, interaction, interaction

    PubMed Central

    Joel, D; Yankelevitch-Yahav, R

    2014-01-01

    In recent years there has been a growing recognition of the influence of sex on brain structure and function, and in relation, on the susceptibility, prevalence and response to treatment of psychiatric disorders. Most theories and descriptions of the effects of sex on the brain are dominated by an analogy to the current interpretation of the effects of sex on the reproductive system, according to which sex is a divergence system that exerts a unitary, overriding and serial effect on the form of other systems. We shortly summarize different lines of evidence that contradict aspects of this analogy. The new view that emerges from these data is of sex as a complex system whose different components interact with one another and with other systems to affect body and brain. The paradigm shift that this understanding calls for is from thinking of sex in terms of sexual dimorphism and sex differences, to thinking of sex in terms of its interactions with other factors and processes. Our review of data obtained from animal models of psychopathology clearly reveals the need for such a paradigmatic shift, because in the field of animal behaviour whether a sex difference exists and its direction depend on the interaction of many factors including, species, strain, age, specific test employed and a multitude of environmental factors. We conclude by explaining how the new conceptualization can account for sex differences in psychopathology. Linked Articles This article is part of a themed section on Animal Models in Psychiatry Research. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-20 PMID:24758640

  8. Parallel PIC Simulations of Ultra-High Intensity Laser Plasma Interactions.

    NASA Astrophysics Data System (ADS)

    Lasinski, B. F.; Still, C. H.; Langdon, A. B.; Wilks, S. C.; Hatchett, S. P.; Hinkel, D. E.

    1999-11-01

    We extend our previous simulations of high intensity short pulse laser plasma interactionsfootnote B. F. Lasinski, A. B. Langdon, S. P. Hatchett, M. H. Key, and M. Tabak, Phys. Plasmas 6, 2041 (1999); S. C. Wilks and W. L. Kruer, IEEE Journal of Quantum Electronics 11, 1954 (1997). to 3D and to much larger systems in 2D using our new, modern, 3D, electromagnetic, fully relativistic, massively parallel PIC code. Our simulation parameters are guided by the recent Petawatt experiments at Livermore. We study the generation of hot electrons and energetic ions and the associated complex phenomena. Laser light filamentation and the formation of high static magnetic fields are described.

  9. Interactive Visualization of Dependencies

    ERIC Educational Resources Information Center

    Moreno, Camilo Arango; Bischof, Walter F.; Hoover, H. James

    2012-01-01

    We present an interactive tool for browsing course requisites as a case study of dependency visualization. This tool uses multiple interactive visualizations to allow the user to explore the dependencies between courses. A usability study revealed that the proposed browser provides significant advantages over traditional methods, in terms of…

  10. University-industry interaction

    NASA Technical Reports Server (NTRS)

    Hastings, Daniel E.

    1990-01-01

    It is posited that university industry interaction is highly desirable from the viewpoint of the long term economic development of the country as well as being desirable for the Space Grant Programs. The present and future possible interactions are reviewed for the three university levels namely, undergraduate, graduate, and faculty research.

  11. Interactive Videodisc Learning Systems.

    ERIC Educational Resources Information Center

    Currier, Richard L.

    1983-01-01

    Interactive videodisc makes possible a powerful educational experience in which computer-based educational systems can display video imagery, real-time action, and stereo sound. Interactivity, teaching with videodisc, electronic tutors, videodisc technologies, and costs are among the topics discussed. Use of videodisc for games and simulating…

  12. Oral contraceptive drug interactions.

    PubMed

    Baciewicz, A M

    1985-01-01

    Approximately 50 million women use oral contraceptives (OC). Studies and case reports demonstrate that OC failure may be caused by rifampin, anticonvulsant drugs, and possibly some antibiotics. Contraceptive steroids may interfere with the metabolism of the benzodiazepines, theophylline, and the glucocorticoids. Future investigation will document the clinical significance of other OC interactions as well as give rise to new interactions. PMID:2859674

  13. What Is Interactivity?

    ERIC Educational Resources Information Center

    Smuts, Aaron

    2009-01-01

    In this article, the author attempts to develop a definition of "interactivity" that meets two sometimes incompatible goals: the definition should be in accord with the best intuitions on how the term should be used, and it should usefully differentiate interactivity from related but incompatible concepts with which it is often confused. The…

  14. Visualizing Dispersion Interactions

    ERIC Educational Resources Information Center

    Gottschalk, Elinor; Venkataraman, Bhawani

    2014-01-01

    An animation and accompanying activity has been developed to help students visualize how dispersion interactions arise. The animation uses the gecko's ability to walk on vertical surfaces to illustrate how dispersion interactions play a role in macroscale outcomes. Assessment of student learning reveals that students were able to develop…

  15. The Interaction Equivalency Theorem

    ERIC Educational Resources Information Center

    Miyazoe, Terumi; Anderson, Terry

    2010-01-01

    This paper examines the key issues regarding The Interaction Equivalency Theorem posited by Anderson (2003a), which consists of the three interaction elements found in formal education courses among teacher, student, and content. It first examines the core concepts of the theorem and argues that two theses of different dimensions can be…

  16. Interactive TV: The Sequel.

    ERIC Educational Resources Information Center

    Brown, Eric

    1998-01-01

    Examines the future of interactive TV where consumers navigate the Internet on their TVs with WebTV set-top boxes. Focuses on competition between cable companies and computer and consumer electronics companies. Highlights nine companies and partnerships developing interactive hardware and services. (PEN)

  17. Newseum: Open for Interaction.

    ERIC Educational Resources Information Center

    Luck, Brad

    1998-01-01

    Describes a teenage journalist's visit to the Newseum in Washington, DC, the world's only interactive museum dedicated to news. Describes visiting the Interactive Newsroom, the huge News Globe, the News History Gallery, and the Broadcast Studio. Describes also a brief visit to Freedom Park and the Newseum Education Center. Notes the enthusiasm of…

  18. Interactive Presentation of Content

    ERIC Educational Resources Information Center

    Magdin, Martin; Turcáni, Milan; Vrábel, Marek

    2009-01-01

    In the paper we discus about design of universal environment for solution of creating effective multimedia applications with accent on the implementation of interactive elements with the possibility of using the adaptive systems (AS). We also discuss about possibilities of offline presentation of this interactive multimedia adaptive animations…

  19. LIA: LWS Interactive Analysis

    NASA Astrophysics Data System (ADS)

    Infrared Space Observatory (ISO) Development Team

    2014-08-01

    The Long Wavelength Spectrometer (LWS) was one of two complementary spectrometers on the Infrared Space Observatory (ISO). LIA (LWS Interactive Analysis) is used for processing data from the LWS. It provides access to the different processing steps, including visualization of intermediate products and interactive manipulation of the data at each stage.

  20. Media Embedded Interactions.

    ERIC Educational Resources Information Center

    Johnson, J. David

    A review of literature and two surveys, one of college students and one of a random sample of adults, were used to examine four aspects of media embedded interactions (social behavior in front of a TV or radio): their functions, their environment, their effects, and the reactions of the interactants to them. Television is seen as performing a…

  1. Let Social Interaction Flourish

    ERIC Educational Resources Information Center

    Case, Anny Fritzen

    2016-01-01

    The author describes lessons learned--through a high school project that grouped English language learners with native speakers to create a video--about ways to foster respectful, productive interaction among English learners and peers who are native speakers. The potential benefits of students who are just learning English interacting socially…

  2. Return current and proton emission from wire targets interacting with an intense short pulse laser

    NASA Astrophysics Data System (ADS)

    Beg, Farhat

    2004-05-01

    One of the important characteristics of short pulse high intensity laser-solid interactions is the generation of energetic charged particles, which result from the very efficient conversion of laser energy into hot electrons. Since the electrons in the electric field of the laser have relativistic quiver motions, the temperature of the hot electron distribution of the plasma produced at such extreme intensities can become very high. A large number of hot electrons (1013-1014) having an average energy of the order of 1-2 MeV can be generated as intensities exceed 1019 Wcm-2. Since the resulting beam current exceeds the Alfvén limit, a neutralizing return current of cold plasma electrons moving in the opposite direction is produced. Another source of return current is that due to the escape of very energetic electrons from the target, which then creates a large electrostatic potential due to charge separation. These return currents can cause significant ohmic heating. In addition escaping electrons establish the large electrostatic fields, accelerating a large number of protons from the target with energies of 10's of MeV. The experiments reported here were performed at the Rutherford Appleton Laboratory with the VULCAN laser facility at intensity greater than 5 x1019 Wcm-2 on wire targets. In some shots an additional wire or foil was placed nearby. The laser was blocked by the main wire target so that no laser light reached the additional wire or foil. Three main observations were made: (i) a Z-pinch was driven in the wire due to the return current, (ii) optical transition radiation (OTR) at 2w was generated and (iii) energetic proton emission was observed. The wire targets were observed to be ohmically heated and were m=0 unstable. The OTR emission is likely due to electron bunches accelerated by the ponderomotive force of the laser. The proton emission was in a form of thin disk perpendicular to the wire and centered on the wire at the laser focus. Proton

  3. Spacelab user interaction

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The results of the third and final phase of a study undertaken to define means of optimizing the Spacelab experiment data system by interactively manipulating the flow of data were presented. A number of payload applicable interactive techniques and an integrated interaction system for each of two possible payloads are described. These interaction systems have been functionally defined and are accompanied with block diagrams, hardware specifications, software sizing and speed requirements, operational procedures and cost/benefits analysis data for both onboard and ground based system elements. It is shown that accrued benefits are attributable to a reduction in data processing costs obtained by, generally, a considerable reduction in the quantity of data that might otherwise be generated without interaction. One other additional anticipated benefit includes the increased scientific value obtained by the quicker return of all useful data.

  4. Legacy Systems Interaction Reengineering

    NASA Astrophysics Data System (ADS)

    El-Ramly, Mohammad; Stroulia, Eleni; Samir, Hani

    We present a lightweight approach for reengineering the human computer interaction (HCI) and/or interaction with other software systems. While interaction reengineering can be achieved by changing the source code and design (e.g., library replacement, refactoring, etc.) resulting in a different user interface (UI), we limit the discussion to interaction reengineering methods that do not involve changing the source code or internal design of the system. Instead, we focus on methods and techniques for wrapping and packaging the existing interaction layer to reproduce it in a different format, e.g., on a different platform or to integrate the legacy system services in another application possibly under a different architecture paradigm, e.g., service-oriented architectures (SOA).

  5. Leo space plasma interactions

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.

    1991-01-01

    Photovoltaic arrays interact with the low earth orbit (LEO) space plasma in two fundamentally different ways. One way is the steady collection of current from the plasma onto exposed conductors and semiconductors. The relative currents collected by different parts of the array will then determine the floating potential of the spacecraft. In addition, these steady state collected currents may lead to sputtering or heating of the array by the ions or electrons collected, respectively. The second kind of interaction is the short time scale arc into the space plasma, which may deplete the array and/or spacecraft of stored charge, damage solar cells, and produce EMI. Such arcs only occur at high negative potentials relative to the space plasma potential, and depend on the steady state ion currents being collected. New high voltage solar arrays being incorporated into advanced spacecraft and space platforms may be endangered by these plasma interactions. Recent advances in laboratory testing and current collection modeling promise the capability of controlling, and perhaps even using, these space plasma interactions to enable design of reliable high voltage space power systems. Some of the new results may have an impact on solar cell spacing and/or coverslide design. Planned space flight experiments are necessary to confirm the models of high voltage solar array plasma interactions. Finally, computerized, integrated plasma interactions design tools are being constructed to place plasma interactions models into the hands of the spacecraft designer.

  6. The ADAMS interactive interpreter

    SciTech Connect

    Rietscha, E.R.

    1990-12-17

    The ADAMS (Advanced DAta Management System) project is exploring next generation database technology. Database management does not follow the usual programming paradigm. Instead, the database dictionary provides an additional name space environment that should be interactively created and tested before writing application code. This document describes the implementation and operation of the ADAMS Interpreter, an interactive interface to the ADAMS data dictionary and runtime system. The Interpreter executes individual statements of the ADAMS Interface Language, providing a fast, interactive mechanism to define and access persistent databases. 5 refs.

  7. Adverse Drug Interactions

    PubMed Central

    Becker, Daniel E.

    2011-01-01

    The potential for interactions with current medications should always be considered when administering or prescribing any drug. Considering the staggering number of drugs patients may be taking, this task can be daunting. Fortunately, drug classes employed in dental practice are relatively few in number and therapy is generally brief in duration. While this reduces the volume of potential interactions, there are still a significant number to be considered. This article will review basic principles of drug interactions and highlight those of greatest concern in dental practice. PMID:21410363

  8. Atomic & Molecular Interactions

    SciTech Connect

    2002-07-12

    The Gordon Research Conference (GRC) on Atomic & Molecular Interactions was held at Roger Williams University, Bristol, RI. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  9. Interactive Office user's manual

    NASA Technical Reports Server (NTRS)

    Montgomery, Edward E.; Lowers, Benjamin; Nabors, Terri L.

    1990-01-01

    Given here is a user's manual for Interactive Office (IO), an executive office tool for organization and planning, written specifically for Macintosh. IO is a paperless management tool to automate a related group of individuals into one productive system.

  10. Neutrino self-interactions

    NASA Astrophysics Data System (ADS)

    Hasenkamp, Jasper

    2016-03-01

    We propose a theory that equips the active neutrinos with interactions among themselves that are at least 3 orders of magnitude stronger than the weak interaction. We introduce an Abelian gauge group U (1 )X with vacuum expectation value vx≲O (100 MeV ) . An asymmetric mass matrix implements the active neutrinos as massless mass eigenstates carrying "effective" charges. To stabilize vx, supersymmetry breaking is mediated via loops to the additional sector with the only exception of xHiggs terms. No Standard Model interaction eigenstate carries U (1 )X charge. Thus, the dark photon's kinetic mixing is two-loop suppressed. With only simple and generic values of dimensionless parameters, our theory might explain the high-energy neutrino spectrum observed by IceCube including the PeV neutrinos. We comment on the imposing opportunity to incorporate a self-interacting dark matter candidate.