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Sample records for laser-driven nonlinear cluster

  1. Laser-driven nonlinear cluster dynamics

    SciTech Connect

    Fennel, Th.; Meiwes-Broer, K.-H.; Tiggesbaeumker, J.; Reinhard, P.-G.; Dinh, P. M.; Suraud, E.

    2010-04-15

    Laser excitation of nanometer-sized atomic and molecular clusters offers various opportunities to explore and control ultrafast many-particle dynamics. Whereas weak laser fields allow the analysis of photoionization, excited-state relaxation, and structural modifications on these finite quantum systems, large-amplitude collective electron motion and Coulomb explosion can be induced with intense laser pulses. This review provides an overview of key phenomena arising from laser-cluster interactions with focus on nonlinear optical excitations and discusses the underlying processes according to the current understanding. A general survey covers basic cluster properties and excitation mechanisms relevant for laser-driven cluster dynamics. Then, after an excursion in theoretical and experimental methods, results for single-photon and multiphoton excitations are reviewed with emphasis on signatures from time- and angular-resolved photoemission. A key issue of this review is the broad spectrum of phenomena arising from clusters exposed to strong fields, where the interaction with the laser pulse creates short-lived and dense nanoplasmas. The implications for technical developments such as the controlled generation of ion, electron, and radiation pulses will be addressed along with corresponding examples. Finally, future prospects of laser-cluster research as well as experimental and theoretical challenges are discussed.

  2. Laser-driven Acceleration in Clustered Plasmas

    SciTech Connect

    Gao, X.; Wang, X.; Shim, B.; Downer, M. C.

    2009-01-22

    We propose a new approach to avoid dephasing limitation of laser wakefield acceleration by manipulating the group velocity of the driving pulse using clustered plasmas. We demonstrated the control of phase velocity in clustered plasmas by third harmonic generation and frequency domain interferometry experiments. The results agree with a numerical model. Based on this model, the group velocity of the driving pulse in clustered plasmas was calculated and the result shows the group velocity can approach the speed of light c in clustered plasmas.

  3. Nonlinear Laser Driven Donut Wakefields for Positron and Electron Acceleration

    NASA Astrophysics Data System (ADS)

    Vieira, J.; Mendonça, J. T.

    2014-05-01

    We show analytically and through three-dimensional particle-in-cell simulations that nonlinear wakefields driven by Laguerre-Gaussian laser pulses can lead to hollow electron self-injection and positron acceleration. We find that higher order lasers can drive donut shaped blowout wakefields with strong positron accelerating gradients comparable to those of a spherical bubble. Corresponding positron focusing forces can be more than an order of magnitude stronger than electron focusing forces in a spherical bubble. Required laser intensities and energies to reach the nonlinear donut shaped blowout are within state-of-the-art experimental conditions.

  4. Femtosecond-Laser-Driven Cluster-Based Plasma Source for High-Resolution Ionography

    NASA Astrophysics Data System (ADS)

    Faenov, A. Ya.; Pikuz, T. A.; Fukuda, Y.; Kando, M.; Kotaki, H.; Homma, T.; Kawase, K.; Kameshima, T.; Pirozhkov, A.; Yogo, A.; Tampo, M.; Mori, M.; Sakaki, H.; Hayashi, Y.; Nakamura, T.; Pikuz, S. A.; Kartashev, V.; Skobelev, I. Yu.; Gasilov, S. V.; Giulietti, A.; Cecchetti, C. A.; Boldarev, A. S.; Gasilov, V. A.; Magunov, A.; Kar, S.; Borghesi, M.; Bolton, P.; Daido, H.; Tajima, T.; Kato, Y.; Bulanov, S. V.

    2009-07-01

    The intense isotropic source of multicharged ions, with energy above 300 keV, was produced by femtosecond Ti:Sa laser pulses irradiation (intensity of ˜4×1017 W/cm2) of the He and CO2 gases mixture expanded in supersonic jet. High contrast ionography images have been obtained for 2000 dpi metal mesh, 1 μm polypropylene and 100 nm Zr foils, as well as for different biological objects. Images were recorded on 1 mm thick CR-39 ion detector placed in contact with back surface of the imaged samples, at the distances 140-160 mm from the plasma source. The obtained spatial resolution of the image was ˜600 nm. A 100 nm object thickness difference was resolved very well for both Zr and polymer foils. The multicharged ion energy for Carbon and Oxygen ions passing through the 1 μm polypropylene foil is estimated to give the energy of more than 300 keV. An almost equal number of ions were measured with total number of about 108 per shot at a different direction from plasma source. Easy production of different sub-MeV ions in wide space angle, recognizes femtosecond-laser-driven-cluster-based plasma as a well-suited bright source for novel type of submicron ionography to image different media, including nanofoils, membranes, and other low-contrast objects.

  5. Revealing the second harmonic generation in a femtosecond laser-driven cluster-based plasma by analyzing shapes of Ar XVII spectral lines.

    PubMed

    Oks, Eugene; Dalimier, Elisabeth; Faenov, Anatoly; Pikuz, Tatiana; Fukuda, Yuji; Andreev, Alexander; Koga, James; Sakaki, Hironao; Kotaki, Hideyuki; Pirozhkov, Alexander; Hayashi, Yukio; Skobelev, Igor; Pikuz, Sergei; Kawachi, Tetsuya; Kando, Masaki; Kondo, Kiminori; Zhidkov, Alexei; Kodama, Ryosuke

    2015-12-14

    We present experiments dealing with a femtosecond laser-driven cluster-based plasma, where by analyzing the nonlinear phenomenon of satellites of spectral lines of Ar XVII, we revealed the nonlinear phenomenon of the generation of the second harmonic of the laser frequency. For performing this analysis we developed new results in the theory of satellites of spectral lines. From such lineshape analysis we found, in particular, that the efficiency of converting the short (40 fs) intense (3x10¹⁸ W/cm²) incident laser light into the second harmonic was 2%. This result is in the excellent agreement with the 2-Dimensional Particle-In-Cell (2D PIC) simulation that we also performed. There is also an order of magnitude agreement between the thresholds for the SHG found from the line shape analysis and from the 2D PIC simulations. PMID:26698990

  6. Magnetic Field Generation by the Nonlinear Rayleigh--Taylor Instability in Laser-Driven Planar Plastic Targets

    NASA Astrophysics Data System (ADS)

    Gao, L.; Igumenshchev, I. V.; Hu, S. X.; Stoeckl, C.; Froula, D. H.; Nilson, P. M.; Davies, J. R.; Betti, R.; Meyerhofer, D. D.; Haines, M. G.

    2012-10-01

    Magnetic field generation during the nonlinear phase of the Rayleigh--Taylor (RT) instability in an ablatively driven plasma using ultrafast laser-driven proton radiography has been measured. Thin plastic foils were irradiated with ˜4-kJ, 2.5-ns laser pulses focused to an intensity of ˜10^14 W/cm^2 on the OMEGA EP Laser System. Target modulations were seeded by laser nonuniformities and amplified during target acceleration by the RT instability. The experimental data show the hydrodynamic evolution of the target and MG-level magnetic fields generated in the broken foil. The experimental data are in good agreement with predictions from 2-D magnetohydrodynamic simulations. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302.

  7. Relativistic warm plasma theory of nonlinear laser-driven electron plasma waves.

    PubMed

    Schroeder, C B; Esarey, E

    2010-05-01

    A relativistic, warm fluid model of a nonequilibrium, collisionless plasma is developed and applied to examine nonlinear Langmuir waves excited by relativistically intense, short-pulse lasers. Closure of the covariant fluid theory is obtained via an asymptotic expansion assuming a nonrelativistic plasma temperature. The momentum spread is calculated in the presence of an intense laser field and shown to be intrinsically anisotropic. Coupling between the transverse and longitudinal momentum variances is enabled by the laser field. A generalized dispersion relation is derived for Langmuir waves in a thermal plasma in the presence of an intense laser field. Including thermal fluctuations in three-velocity-space dimensions, the properties of the nonlinear electron plasma wave, such as the plasma temperature evolution and nonlinear wavelength, are examined and the maximum amplitude of the nonlinear oscillation is derived. The presence of a relativistically intense laser pulse is shown to strongly influence the maximum plasma wave amplitude for nonrelativistic phase velocities owing to the coupling between the longitudinal and transverse momentum variances. PMID:20866340

  8. Relativistic warm plasma theory of nonlinear laser-driven electron plasma waves

    SciTech Connect

    Schroeder, Carl B.; Esarey, Eric

    2010-06-30

    A relativistic, warm fluid model of a nonequilibrium, collisionless plasma is developed and applied to examine nonlinear Langmuir waves excited by relativistically-intense, short-pulse lasers. Closure of the covariant fluid theory is obtained via an asymptotic expansion assuming a non-relativistic plasma temperature. The momentum spread is calculated in the presence of an intense laser field and shown to be intrinsically anisotropic. Coupling between the transverse and longitudinal momentum variances is enabled by the laser field. A generalized dispersion relation is derived for langmuir waves in a thermal plasma in the presence of an intense laser field. Including thermal fluctuations in three velocity-space dimensions, the properties of the nonlinear electron plasma wave, such as the plasma temperature evolution and nonlinear wavelength, are examined, and the maximum amplitude of the nonlinear oscillation is derived. The presence of a relativistically intense laser pulse is shown to strongly influence the maximum plasma wave amplitude for non-relativistic phase velocities owing to the coupling between the longitudinal and transverse momentum variances.

  9. Nonlinear pulse propagation and phase velocity of laser-driven plasma waves

    SciTech Connect

    Schroeder, Carl B.; Benedetti, Carlo; Esarey, Eric; Leemans, Wim

    2011-03-25

    Laser evolution and plasma wave excitation by a relativistically-intense short-pulse laser in underdense plasma are investigated in the broad pulse limit, including the effects of pulse steepening, frequency red-shifting, and energy depletion. The nonlinear plasma wave phase velocity is shown to be significantly lower than the laser group velocity and further decreases as the pulse propagates owing to laser evolution. This lowers the thresholds for trapping and wavebreaking, and reduces the energy gain and efficiency of laser-plasma accelerators that use a uniform plasma profile.

  10. Electronic excitation as a mode of heat dissipation in laser-driven cluster plasmas

    SciTech Connect

    Rajeev, R.; Rishad, K. P. M.; Madhu Trivikram, T.; Krishnamurthy, M.

    2013-12-15

    Electrons streaming out of laser plasma are known for non-local heat transport and energy deposition by the ionization wave. At 100 eV electron temperature, since the electronic excitation cross section is comparable to that of ionization for Ar and CO{sub 2}, a non-local excitation wave akin to the ionization wave is envisaged where energy deposition in excitations forms a excited cluster sheath beyond the laser focus. Here, we show that nano-cluster systems have the right parameters to form such an exciton sheath and experimentally demonstrate this via charge transfer reactions.

  11. Expansion of nanoplasmas and laser-driven nuclear fusion in single exploding clusters

    SciTech Connect

    Peano, F.; Martins, J. L.; Silva, L. O.; Peinetti, F.; Mulas, R.; Coppa, G.

    2008-09-07

    The expansion of laser-irradiated clusters can be controlled by acting on the amount of energy delivered to the electrons. When increasing the electron energy, the expansion regime varies smoothly from a quasineutral, hydrodinamic-like to a Coulomb explosion (CE), as revealed by self-consistent kinetic analysis. A double-pump irradiation scheme can produce hybrid expansion regimes wherein a slow hydrodynamic expansion is followed by a fast CE, leading to ion overtaking and producing multiple ion flows expanding with different velocities, which can lead to intracluster fusion reactions in homonuclear deuterium clusters.

  12. Steplike Intensity Threshold Behavior of Extreme Ionization in Laser-Driven Xenon Clusters

    SciTech Connect

    Doeppner, T.; Mueller, J. P.; Przystawik, A.; Goede, S.; Tiggesbaeumker, J.; Meiwes-Broer, K.-H.; Varin, C.; Ramunno, L.; Brabec, T.; Fennel, T.

    2010-07-30

    The generation of highly charged Xe{sup q+} ions up to q=24 is observed in Xe clusters embedded in helium nanodroplets and exposed to intense femtosecond laser pulses ({lambda}=800 nm). Laser intensity resolved measurements show that the high-q ion generation starts at an unexpectedly low threshold intensity of about 10{sup 14} W/cm{sup 2}. Above threshold, the Xe ion charge spectrum saturates quickly and changes only weakly for higher laser intensities. Good agreement between these observations and a molecular dynamics analysis allows us to identify the mechanisms responsible for the highly charged ion production and the surprising intensity threshold behavior of the ionization process.

  13. Bright betatron X-ray radiation from a laser-driven-clustering gas target.

    PubMed

    Chen, L M; Yan, W C; Li, D Z; Hu, Z D; Zhang, L; Wang, W M; Hafz, N; Mao, J Y; Huang, K; Ma, Y; Zhao, J R; Ma, J L; Li, Y T; Lu, X; Sheng, Z M; Wei, Z Y; Gao, J; Zhang, J

    2013-01-01

    Hard X-ray sources from femtosecond (fs) laser-produced plasmas, including the betatron X-rays from laser wakefield-accelerated electrons, have compact sizes, fs pulse duration and fs pump-probe capability, making it promising for wide use in material and biological sciences. Currently the main problem with such betatron X-ray sources is the limited average flux even with ultra-intense laser pulses. Here, we report ultra-bright betatron X-rays can be generated using a clustering gas jet target irradiated with a small size laser, where a ten-fold enhancement of the X-ray yield is achieved compared to the results obtained using a gas target. We suggest the increased X-ray photon is due to the existence of clusters in the gas, which results in increased total electron charge trapped for acceleration and larger wiggling amplitudes during the acceleration. This observation opens a route to produce high betatron average flux using small but high repetition rate laser facilities for applications. PMID:23715033

  14. Bright betatron X-ray radiation from a laser-driven-clustering gas target

    PubMed Central

    Chen, L. M.; Yan, W. C.; Li, D. Z.; Hu, Z. D.; Zhang, L.; Wang, W. M.; Hafz, N.; Mao, J. Y.; Huang, K.; Ma, Y.; Zhao, J. R.; Ma, J. L.; Li, Y. T.; Lu, X.; Sheng, Z. M.; Wei, Z. Y.; Gao, J.; Zhang, J.

    2013-01-01

    Hard X-ray sources from femtosecond (fs) laser-produced plasmas, including the betatron X-rays from laser wakefield-accelerated electrons, have compact sizes, fs pulse duration and fs pump-probe capability, making it promising for wide use in material and biological sciences. Currently the main problem with such betatron X-ray sources is the limited average flux even with ultra-intense laser pulses. Here, we report ultra-bright betatron X-rays can be generated using a clustering gas jet target irradiated with a small size laser, where a ten-fold enhancement of the X-ray yield is achieved compared to the results obtained using a gas target. We suggest the increased X-ray photon is due to the existence of clusters in the gas, which results in increased total electron charge trapped for acceleration and larger wiggling amplitudes during the acceleration. This observation opens a route to produce high betatron average flux using small but high repetition rate laser facilities for applications. PMID:23715033

  15. Laser driven high energy density radiative blast waves launched in clustered gases

    NASA Astrophysics Data System (ADS)

    Olsson-Robbie, Stefan; Doyle, Hugo; Lowe, Hazel; Price, Chris; Bigourd, Damien; Patankar, Siddharth; Mecseki, Katalin; Booth, Nicola; Scott, Robbie; Moore, Alastair; Hohenberger, Matthias; Rodriguez, Rafael; Gumbrell, Edward; Symes, Daniel; Smith, Roland

    2012-10-01

    Intense lasers deposit energy efficiently in clustered gases creating hot plasma with low density, conditions ideal for launching radiative blast waves (BWs) of interest for laboratory astrophysics (LA). We report measurements in a range of gases irradiated by the Astra-Gemini laser with energies >10J. Optical imaging, self emission and temporally resolved x-ray spectra are used to characterise BW evolution. The high repetition rate of the laser allows us to explore the influence of atomic number and density on the BW dynamics. Altering the emitted radiation and opacity of the medium has a strong effect on the BW profile and energy loss. Strongly radiative BWs exhibit shell thinning, increasing their susceptibility to instabilities. We have demonstrated the onset of a velocity instability, driven by the exchange of energy between the shock and precursor in krypton BWs. We discuss the threshold conditions for this behaviour and the potential to study spatial shock front instabilities. Our results will be compared to simulations and analytical calculations with a view to designing scalable LA experiments.

  16. Laser-Driven Fusion.

    ERIC Educational Resources Information Center

    Gibson, A. F.

    1980-01-01

    Discusses the present status and future prospects of laser-driven fusion. Current research (which is classified under three main headings: laser-matter interaction processes, compression, and laser development) is also presented. (HM)

  17. Electron spectra of xenon clusters irradiated with a laser-driven plasma soft-x-ray laser pulse

    SciTech Connect

    Namba, S.; Takiyama, K.; Hasegawa, N.; Kishimoto, M.; Nishikino, M.; Kawachi, T.

    2011-11-15

    Xenon clusters were irradiated with plasma soft-x-ray laser pulses (having a wavelength of 13.9 nm, time duration of 7 ps, and intensities of up to 10 GW/cm{sup 2}). The laser photon energy was high enough to photoionize 4d core electrons. The cross section is large due to a giant resonance. The interaction was investigated by measuring the electron energy spectra. The photoelectron spectra for small clusters indicate that the spectral width due to the 4d hole significantly broadens with increasing cluster size. For larger clusters, the electron energy spectra evolve into a Maxwell-Boltzmann distribution, as a strongly coupled cluster nanoplasma is generated.

  18. Laser driven radiography

    SciTech Connect

    Perry, M.D.; Sefcik, J.; Cowan, T.

    1997-12-20

    Intense laser (> 1021 W/cm{sup 3}) 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 potential cost advantage for multiple axis views. High spatial and temporal resolution is achievable as a result of the very small source size (<100 um) and short-duration of the laser pulse. We have begun a series of experiments with the Petawatt laser at LLNL to determine the photon flux achievable with these sources and assess their potential for Stewardship applications. Additionally, we are developing a conceptual design and cost estimate of a multi-pulse, multi-axis (up to five) radiographic facility utilizing the Contained Firing Facility at site 300 and existing laser hardware.

  19. Laser-driven fusion reactor

    DOEpatents

    Hedstrom, J.C.

    1973-10-01

    A laser-driven fusion reactor consisting of concentric spherical vessels in which the thermonuclear energy is derived from a deuterium-tritium (D + T) burn within a pellet'', located at the center of the vessels and initiated by a laser pulse. The resulting alpha -particle energy and a small fraction of the neutron energy are deposited within the pellet; this pellet energy is eventually transformed into sensible heat of lithium in a condenser outside the vessels. The remaining neutron energy is dissipated in a lithium blanket, located within the concentric vessels, where the fuel ingredient, tritium, is also produced. The heat content of the blanket and of the condenser lithium is eventually transferred to a conventional thermodynamic plant where the thermal energy is converted to electrical energy in a steam Rankine cycle. (Official Gazette)

  20. Non-linear dark energy clustering

    SciTech Connect

    Anselmi, Stefano; Ballesteros, Guillermo; Pietroni, Massimo E-mail: ballesteros@pd.infn.it

    2011-11-01

    We consider a dark energy fluid with arbitrary sound speed and equation of state and discuss the effect of its clustering on the cold dark matter distribution at the non-linear level. We write the continuity, Euler and Poisson equations for the system in the Newtonian approximation. Then, using the time renormalization group method to resum perturbative corrections at all orders, we compute the total clustering power spectrum and matter power spectrum. At the linear level, a sound speed of dark energy different from that of light modifies the power spectrum on observationally interesting scales, such as those relevant for baryonic acoustic oscillations. We show that the effect of varying the sound speed of dark energy on the non-linear corrections to the matter power spectrum is below the per cent level, and therefore these corrections can be well modelled by their counterpart in cosmological scenarios with smooth dark energy. We also show that the non-linear effects on the matter growth index can be as large as 10–15 per cent for small scales.

  1. Laser driven electron acceleration in vacuum, gases and plasmas

    SciTech Connect

    Sprangle, P.; Esarey, E.; Krall, J.

    1996-04-19

    This paper discusses some of the important issues pertaining to laser acceleration in vacuum, neutral gases and plasmas. The limitations of laser vacuum acceleration as they relate to electron slippage, laser diffraction, material damage and electron aperture effects, are discussed. An inverse Cherenkov laser acceleration configuration is presented in which a laser beam is self guided in a partially ionized gas. Optical self guiding is the result of a balance between the nonlinear self focusing properties of neutral gases and the diffraction effects of ionization. The stability of self guided beams is analyzed and discussed. In addition, aspects of the laser wakefield accelerator are presented and laser driven accelerator experiments are briefly discussed.

  2. Electron Weibel Instability Mediated Laser Driven Electromagnetic Collisionless Shock

    NASA Astrophysics Data System (ADS)

    Jia, Qing; Mima, Kunioki; Cai, Hong-Bo; Taguchi, Toshihiro; Nagatomo, Hideo; He, X. T.

    2015-11-01

    As a fundamental nonlinear structure, collisionless shock is widely studied in astrophysics. Recently, the rapidly-developing laser technology provides a good test-bed to study such shock physics in laboratory. In addition, the laser driven shock ion acceleration is also interested due to its potential applications. We explore the effect of external parallel magnetic field on the collisionless shock formation and resultant particle acceleration by using the 2D3V PIC simulations. We show that unlike the electrostatic shock generated in the unmagnetized plasma, the shock generated in the weakly-magnetized laser-driven plasma is mostly electromagnetic (EM)-like with higher Mach number. The generation mechanism is due to the stronger transverse magnetic field self-generated at the nonlinear stage of the electron Weibel instability which drastically scatters particles and leads to higher energy dissipation. Simulation results also suggest more ions are reflected by this EM shock and results in larger energy transfer rate from the laser to ions, which is of advantage for applications such as neutron production and ion fast ignition.

  3. Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect

    Cowan, B.; /SLAC

    2005-09-19

    We discuss simulated photonic crystal structure designs for laser-driven particle acceleration, focusing on three-dimensional planar structures based on the so-called ''woodpile'' lattice. We demonstrate guiding of a speed-of-light accelerating mode by a defect in the photonic crystal lattice and discuss the properties of this mode. We also discuss particle beam dynamics in the structure, presenting a novel method for focusing the beam. In addition we describe some potential coupling methods for the structure.

  4. Fiber optic mounted laser driven flyer plates

    SciTech Connect

    Paisley, D.L.

    1990-12-31

    This invention is comprised of a laser driven flyer plate where the flyer plate is deposited directly onto the squared end of an optical fiber. The plasma generated by a laser pulse drives the flyer plate toward a target. In another embodiment, a first metal layer is deposited onto the squared end of an optical fiber, followed by a layer of a dielectric material and a second metal layer. The laser pulse generates a plasma in the first metal layer, but the plasma is kept away from the second metal layer by the dielectric layer until the pressure reaches the point where shearing occurs. 2 figs.

  5. Visualization of high-dimensional clusters using nonlinear magnification

    SciTech Connect

    Keahey, T.A.

    1998-12-31

    This paper describes a cluster visualization system used for data-mining fraud detection. The system can simultaneously show 6 dimensions of data, and a unique technique of 3D nonlinear magnification allows individual clusters of data points to be magnified while still maintaining a view of the global context. The author first describes the fraud detection problem, along with the data which is to be visualized. Then he describes general characteristics of the visualization system, and shows how nonlinear magnification can be used in this system. Finally he concludes and describes options for further work.

  6. Stop motion microphotography of laser driven plates

    SciTech Connect

    Frank, A.M.; Trott, W.M.

    1994-09-01

    Laser driven plates have been used for several years for high velocity shock wave and impact studies. Recent questions about the integrity and ablation rates of these plates coupled with an improved capability for microscopic stop motion photography led to this study. For these experiments, the plates were aluminum, coated on the ends of optical fibers. A high power laser pulse in the fiber ionizes the aluminum at the fiber/coating interface. The plasma thus created accelerates the remaining aluminum to high velocities, several kilometers per second. We defined {open_quotes}thick{close_quotes} or {open_quotes}thin{close_quotes} coatings as those where a flying plate (flyer) was launched vs. the material being completely ionized. Here we were specifically interested in the thick/thin boundary to develop data for the numerical models attempting to predict flyer behavior.

  7. Laser-driven fusion etching process

    DOEpatents

    Ashby, C.I.H.; Brannon, P.J.; Gerardo, J.B.

    1987-08-25

    The surfaces of solids are etched by a radiation-driven chemical reaction. The process involves exposing a substrate coated with a layer of a reactant material on its surface to radiation, e.g., a laser, to induce localized melting of the substrate which results in the occurrence of a fusion reaction between the substrate and coating material. The resultant reaction product and excess reactant salt are then removed from the surface of the substrate with a solvent which is relatively inert towards the substrate. The laser-driven chemical etching process is especially suitable for etching ionic substrates, e.g., LiNbO/sub 3/, such as used in electro-optical/acousto-optic devices. It is also suitable for applications wherein the etching process is required to produce an etched ionic substrate having a smooth surface morphology or when a very rapid etching rate is desired.

  8. Laser-Driven Mini-Thrusters

    NASA Astrophysics Data System (ADS)

    Sterling, Enrique; Lin, Jun; Sinko, John; Kodgis, Lisa; Porter, Simon; Pakhomov, Andrew V.; Larson, C. William; Mead, Franklin B.

    2006-05-01

    Laser-driven mini-thrusters were studied using Delrin® and PVC (Delrin® is a registered trademark of DuPont) as propellants. TEA CO2 laser (λ = 10.6 μm) was used as a driving laser. Coupling coefficients were deduced from two independent techniques: force-time curves measured with a piezoelectric sensor and ballistic pendulum. Time-resolved ICCD images of the expanding plasma and combustion products were analyzed in order to determine the main process that generates the thrust. The measurements were also performed in a nitrogen atmosphere in order to test the combustion effects on thrust. A pinhole transmission experiment was performed for the study of the cut-off time when the ablation/air breakdown plasma becomes opaque to the incoming laser pulse.

  9. Laser-driven fusion etching process

    DOEpatents

    Ashby, Carol I. H.; Brannon, Paul J.; Gerardo, James B.

    1989-01-01

    The surfaces of solid ionic substrates are etched by a radiation-driven chemical reaction. The process involves exposing an ionic substrate coated with a layer of a reactant material on its surface to radiation, e.g. a laser, to induce localized melting of the substrate which results in the occurrance of a fusion reaction between the substrate and coating material. The resultant reaction product and excess reactant salt are then removed from the surface of the substrate with a solvent which is relatively inert towards the substrate. The laser-driven chemical etching process is especially suitable for etching ionic salt substrates, e.g., a solid inorganic salt such as LiNbO.sub.3, such as used in electro-optical/acousto-optic devices. It is also suitable for applications wherein the etching process is required to produce an etched ionic substrate having a smooth surface morphology or when a very rapid etching rate is desired.

  10. Laser-Driven Mini-Thrusters

    SciTech Connect

    Sterling, Enrique; Lin Jun; Sinko, John; Kodgis, Lisa; Porter, Simon; Pakhomov, Andrew V.; Larson, C. William; Mead, Franklin B. Jr.

    2006-05-02

    Laser-driven mini-thrusters were studied using Delrin registered and PVC (Delrin registered is a registered trademark of DuPont) as propellants. TEA CO2 laser ({lambda} = 10.6 {mu}m) was used as a driving laser. Coupling coefficients were deduced from two independent techniques: force-time curves measured with a piezoelectric sensor and ballistic pendulum. Time-resolved ICCD images of the expanding plasma and combustion products were analyzed in order to determine the main process that generates the thrust. The measurements were also performed in a nitrogen atmosphere in order to test the combustion effects on thrust. A pinhole transmission experiment was performed for the study of the cut-off time when the ablation/air breakdown plasma becomes opaque to the incoming laser pulse.

  11. Physics of laser-driven plasma-based electron accelerators

    SciTech Connect

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

    2009-07-15

    Laser-driven plasma-based accelerators, which are capable of supporting fields in excess of 100 GV/m, are reviewed. This includes the laser wakefield accelerator, the plasma beat wave accelerator, the self-modulated laser wakefield accelerator, plasma waves driven by multiple laser pulses, and highly nonlinear regimes. The properties of linear and nonlinear plasma waves are discussed, as well as electron acceleration in plasma waves. Methods for injecting and trapping plasma electrons in plasma waves are also discussed. Limits to the electron energy gain are summarized, including laser pulse diffraction, electron dephasing, laser pulse energy depletion, and beam loading limitations. The basic physics of laser pulse evolution in underdense plasmas is also reviewed. This includes the propagation, self-focusing, and guiding of laser pulses in uniform plasmas and with preformed density channels. Instabilities relevant to intense short-pulse laser-plasma interactions, such as Raman, self-modulation, and hose instabilities, are discussed. Experiments demonstrating key physics, such as the production of high-quality electron bunches at energies of 0.1-1 GeV, are summarized.

  12. Limit cycles in nonlinear excitation of clusters of classical oscillators

    NASA Astrophysics Data System (ADS)

    De Lauro, E.; De Martino, S.; Falanga, M.; Ixaru, L. Gr.

    2009-10-01

    In this paper we develop a numerical procedure for detecting the existence of limit cycles in nonlinear excitation of clusters of classical harmonic oscillators. Our technique is able to compute also the main parameters of a limit cycle, that is the amplitudes and the period. The numerical method, based on the propagation matrix formalism, is transparent and easy to apply. It may find application in various areas where nonlinear excitations are involved, e.g., sound and mechanic vibrations in musical instruments, ground vibrations in volcanic areas, and sea tides.

  13. Dynamic x-ray imaging of laser-driven nanoplasmas

    NASA Astrophysics Data System (ADS)

    Fennel, Thomas

    2016-05-01

    A major promise of current x-ray science at free electron lasers is the realization of unprecedented imaging capabilities for resolving the structure and ultrafast dynamics of matter with nanometer spatial and femtosecond temporal resolution or even below via single-shot x-ray diffraction. Laser-driven atomic clusters and nanoparticles provide an ideal platform for developing and demonstrating the required technology to extract the ultrafast transient spatiotemporal dynamics from the diffraction images. In this talk, the perspectives and challenges of dynamic x-ray imaging will be discussed using complete self-consistent microscopic electromagnetic simulations of IR pump x-ray probe imaging for the example of clusters. The results of the microscopic particle-in-cell simulations (MicPIC) enable the simulation-assisted reconstruction of corresponding experimental data. This capability is demonstrated by converting recently measured LCLS data into a ultrahigh resolution movie of laser-induced plasma expansion. Finally, routes towards reaching attosecond time resolution in the visualization of complex dynamical processes in matter by x-ray diffraction will be discussed.

  14. Distribution of Ions in Laser-Driven Fusion Reactions

    NASA Astrophysics Data System (ADS)

    Warrens, Mackenzie; Barbarino, Matteo; Bonasera, Aldo; Lattuada, Dario; Group Bonasera Team

    2015-10-01

    Experiments of laser-driven fusion reactions are important for many aspects, such as measuring the cross section of plasma. In the experiments at University of Texas using the Texas Petawatt laser, deuterium clusters of various sizes suspended in 3He gas absorb the laser's energy and are irradiated. The clusters undergo a Coulomb explosion, forming a hot plasma which initiates the reactions. This analysis studies two possible fusions: D(d, 3He)n and 3He(d,p)4He. Signals are recorded using a Faraday cup detector, then transformed and analyzed in energy space. In this work, we investigate if the log-normal distribution is an appropriate description of the energy distribution of the ions. If the log-normal distribution is a good fit, the energy distribution can be thought of as chaotic enough to appear thermalized. The chaos may be due to many-body interactions over long distances, as well as the different charges and masses of the particles involved. Using the well-known S-factor for the two reactions and the extrapolated fits, the number of fusions is calculated and compared with experimental data. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. 1263281.

  15. Progress of Laser-Driven Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Nakajima, Kazuhisa

    2007-07-01

    There is a great interest worldwide in plasma accelerators driven by ultra-intense lasers which make it possible to generate ultra-high gradient acceleration and high quality particle beams in a much more compact size compared with conventional accelerators. A frontier research on laser and plasma accelerators is focused on high energy electron acceleration and ultra-short X-ray and Tera Hertz radiations as their applications. These achievements will provide not only a wide range of sciences with benefits of a table-top accelerator but also a basic science with a tool of ultrahigh energy accelerators probing an unknown extremely microscopic world. Harnessing the recent advance of ultra-intense ultra-short pulse lasers, the worldwide research has made a tremendous breakthrough in demonstrating high-energy high-quality particle beams in a compact scale, so called "dream beams on a table top", which represents monoenergetic electron beams from laser wakefield accelerators and GeV acceleration by capillary plasma-channel laser wakefield accelerators. This lecture reviews recent progress of results on laser-driven plasma based accelerator experiments to quest for particle acceleration physics in intense laser-plasma interactions and to present new outlook for the GeV-range high-energy laser plasma accelerators.

  16. Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect

    Cowan, Benjamin M.

    2007-08-22

    Laser-driven acceleration holds great promise for significantly improving accelerating gradient. However, scaling the conventional process of structure-based acceleration in vacuum down to optical wavelengths requires a substantially different kind of structure. We require an optical waveguide that (1) is constructed out of dielectric materials, (2) has transverse size on the order of a wavelength, and (3) supports a mode with speed-of-light phase velocity in vacuum. Photonic crystals---structures whose electromagnetic properties are spatially periodic---can meet these requirements. We discuss simulated photonic crystal accelerator structures and describe their properties. We begin with a class of two-dimensional structures which serves to illustrate the design considerations and trade-offs involved. We then present a three-dimensional structure, and describe its performance in terms of accelerating gradient and efficiency. We discuss particle beam dynamics in this structure, demonstrating a method for keeping a beam confined to the waveguide. We also discuss material and fabrication considerations. Since accelerating gradient is limited by optical damage to the structure, the damage threshold of the dielectric is a critical parameter. We experimentally measure the damage threshold of silicon for picosecond pulses in the infrared, and determine that our structure is capable of sustaining an accelerating gradient of 300 MV/m at 1550 nm. Finally, we discuss possibilities for manufacturing these structures using common microfabrication techniques.

  17. Progress of Laser-Driven Plasma Accelerators

    SciTech Connect

    Nakajima, Kazuhisa

    2007-07-11

    There is a great interest worldwide in plasma accelerators driven by ultra-intense lasers which make it possible to generate ultra-high gradient acceleration and high quality particle beams in a much more compact size compared with conventional accelerators. A frontier research on laser and plasma accelerators is focused on high energy electron acceleration and ultra-short X-ray and Tera Hertz radiations as their applications. These achievements will provide not only a wide range of sciences with benefits of a table-top accelerator but also a basic science with a tool of ultrahigh energy accelerators probing an unknown extremely microscopic world.Harnessing the recent advance of ultra-intense ultra-short pulse lasers, the worldwide research has made a tremendous breakthrough in demonstrating high-energy high-quality particle beams in a compact scale, so called ''dream beams on a table top'', which represents monoenergetic electron beams from laser wakefield accelerators and GeV acceleration by capillary plasma-channel laser wakefield accelerators. This lecture reviews recent progress of results on laser-driven plasma based accelerator experiments to quest for particle acceleration physics in intense laser-plasma interactions and to present new outlook for the GeV-range high-energy laser plasma accelerators.

  18. Visualization of high-dimensional clusters using nonlinear magnification

    NASA Astrophysics Data System (ADS)

    Keahey, T. A.

    1999-03-01

    This paper describes a visualization system which has been used as part of a data-mining effort to detect fraud and abuse within state medicare programs. The data-mining process generates a set of N attributes for each medicare provider and beneficiary in the state; these attributes can be numeric, categorical, or derived from the scoring proces of the data- mining routines. The attribute list can be considered as an N- dimensional space, which is subsequently partitioned into some fixed number of cluster partitions. The sparse nature of the clustered space provides room for the simultaneous visualization of more than 3 dimensions; examples in the paper will show 6-dimensional visualization. This ability to view higher dimensional data allows the data-mining researcher to compare the clustering effectiveness of the different attributes. Transparency based rendering is also used in conjunction with filtering techniques to provide selective rendering of only those data which are of greatest interest. Nonlinear magnification techniques are used to stretch the N- dimensional space to allow focus on one or more regions of interest while still allowing a view of the global context. The magnification can either be applied globally, or in a constrained fashion to expand individual clusters within the space.

  19. Nonlinear mode coupling and vibrational energy transfer in Yukawa clusters

    NASA Astrophysics Data System (ADS)

    Qiao, Ke; Kong, Jie; Matthews, Lorin; Hyde, Truell

    2015-11-01

    Nonlinear mode coupling and the subsequent vibrational energy transfer that results is an important topic in chemical physics research, ranging from small molecules consisting of several atoms to macromolecules such as those found in proteins and DNA. Nonlinear mode coupling is recognized as the mechanism leading to ergodicity, which is a foundational tenet of statistical mechanics. Over the past two decades, Yukawa systems of particles such as those found in complex plasma, have been shown to be an effective model across a large number of physical systems. In this research, nonlinear mode coupling in Yukawa clusters consisting of 3-10 particles is examined via numerical simulation of the vibrational energy transfer between modes starting from an initial excited state. The relationship between the energy transfer process and the internal resonance between modes having a specified frequency ratio and the temporal evolution of the system to a state of equal energy across all modes, i.e., the state of ergodicity, will be discussed. Support from the NSF and the DOE (award numbers PHY-1262031 and PHY-1414523) is gratefully acknowledged.

  20. Proposed Laser-driven, Dielectric Microstructure Few-cm Long Undulator for Attosecond Coherent X-rays

    SciTech Connect

    Plettner, T; Byer, R.L.; /Stanford U., Ginzton Lab.

    2011-09-16

    This article presents the concept of an all-dielectric laser-driven undulator for the generation of coherent X-rays. The proposed laser-driven undulator is expected to produce internal deflection forces equivalent to a several-Tesla magnetic field acting on a speed-of-light particle. The key idea for this laser-driven undulator is its ability to provide phase synchronicity between the deflection force and the electron beam for a distance that is much greater than the laser wavelength. The potential advantage of this undulator is illustrated with a possible design example that assumes a small laser accelerator which delivers a 2 GeV, 1 pC, 1 kHz electron bunch train to a 10 cm long, 1/2 mm period laser-driven undulator. Such an undulator could produce coherent X-ray pulses with {approx}10{sup 9} photons of 64 keV energy. The numerical modeling for the expected X-ray pulse shape was performed with GENESIS, which predicts X-ray pulse durations in the few-attosecond range. Possible applications for nonlinear electromagnetic effects from these X-ray pulses are briefly discussed.

  1. All-laser-driven Thomson X-ray sources

    NASA Astrophysics Data System (ADS)

    Umstadter, Donald P.

    2015-10-01

    We discuss the development of a new generation of accelerator-based hard X-ray sources driven exclusively by laser light. High-intensity laser pulses serve the dual roles: first, accelerating electrons by laser-driven plasma wakefields, and second, generating X-rays by inverse Compton scattering. Such all-laser-driven X-rays have recently been demonstrated to be energetic, tunable, relatively narrow in bandwidth, short pulsed and well collimated. Such characteristics, especially from a compact source, are highly advantageous for numerous advanced X-ray applications - in metrology, biomedicine, materials, ultrafast phenomena, radiology and fundamental physics.

  2. Characterisation of electron beams from laser-driven particle accelerators

    SciTech Connect

    Brunetti, E.; Manahan, G. G.; Shanks, R. P.; Islam, M. R.; Ersfeld, B.; Anania, M. P.; Cipiccia, S.; Issac, R. C.; Vieux, G.; Welsh, G. H.; Wiggins, S. M.; Jaroszynski, D. A.

    2012-12-21

    The development, understanding and application of laser-driven particle accelerators require accurate measurements of the beam properties, in particular emittance, energy spread and bunch length. Here we report measurements and simulations showing that laser wakefield accelerators can produce beams of quality comparable to conventional linear accelerators.

  3. Voids and constraints on nonlinear clustering of galaxies

    NASA Technical Reports Server (NTRS)

    Vogeley, Michael S.; Geller, Margaret J.; Park, Changbom; Huchra, John P.

    1994-01-01

    Void statistics of the galaxy distribution in the Center for Astrophysics Redshift Survey provide strong constraints on galaxy clustering in the nonlinear regime, i.e., on scales R equal to or less than 10/h Mpc. Computation of high-order moments of the galaxy distribution requires a sample that (1) densely traces the large-scale structure and (2) covers sufficient volume to obtain good statistics. The CfA redshift survey densely samples structure on scales equal to or less than 10/h Mpc and has sufficient depth and angular coverage to approach a fair sample on these scales. In the nonlinear regime, the void probability function (VPF) for CfA samples exhibits apparent agreement with hierarchical scaling (such scaling implies that the N-point correlation functions for N greater than 2 depend only on pairwise products of the two-point function xi(r)) However, simulations of cosmological models show that this scaling in redshift space does not necessarily imply such scaling in real space, even in the nonlinear regime; peculiar velocities cause distortions which can yield erroneous agreement with hierarchical scaling. The underdensity probability measures the frequency of 'voids' with density rho less than 0.2 -/rho. This statistic reveals a paucity of very bright galaxies (L greater than L asterisk) in the 'voids.' Underdensities are equal to or greater than 2 sigma more frequent in bright galaxy samples than in samples that include fainter galaxies. Comparison of void statistics of CfA samples with simulations of a range of cosmological models favors models with Gaussian primordial fluctuations and Cold Dark Matter (CDM)-like initial power spectra. Biased models tend to produce voids that are too empty. We also compare these data with three specific models of the Cold Dark Matter cosmogony: an unbiased, open universe CDM model (omega = 0.4, h = 0.5) provides a good match to the VPF of the CfA samples. Biasing of the galaxy distribution in the 'standard' CDM model

  4. X-ray laser driven gold targets

    SciTech Connect

    Petrova, Tz. B. Whitney, K. G.; Davis, J.

    2014-03-15

    The femtosecond population dynamics of gold irradiated by a coherent high-intensity (>10{sup 17} W/cm{sup 2}) x-ray laser pulse is investigated theoretically. There are two aspects to the assembled model. One is the construction of a detailed model of platinum-like gold inclusive of all inner-shell states that are created by photoionization of atomic gold and decay either by radiative or Auger processes. Second is the computation of the population dynamics that ensues when an x-ray pulse is absorbed in gold. The hole state generation depends on the intensity and wavelength of the driving x-ray pulse. The excited state populations reached during a few femtosecond timescales are high enough to generate population inversions, whose gain coefficients are calculated. These amplified lines in the emitted x-ray spectrum provide important diagnostics of the radiation dynamics and also suggest a nonlinear way to increase the frequency of the coherent output x-ray pulses relative to the frequency of the driver input x-ray pulse.

  5. Picosecond metrology of laser-driven proton bursts

    NASA Astrophysics Data System (ADS)

    Dromey, B.; Coughlan, M.; Senje, L.; Taylor, M.; Kuschel, S.; Villagomez-Bernabe, B.; Stefanuik, R.; Nersisyan, G.; Stella, L.; Kohanoff, J.; Borghesi, M.; Currell, F.; Riley, D.; Jung, D.; Wahlström, C.-G.; Lewis, C. L. S.; Zepf, M.

    2016-02-01

    Tracking primary radiation-induced processes in matter requires ultrafast sources and high precision timing. While compact laser-driven ion accelerators are seeding the development of novel high instantaneous flux applications, combining the ultrashort ion and laser pulse durations with their inherent synchronicity to trace the real-time evolution of initial damage events has yet to be realized. Here we report on the absolute measurement of proton bursts as short as 3.5+/-0.7 ps from laser solid target interactions for this purpose. Our results verify that laser-driven ion acceleration can deliver interaction times over a factor of hundred shorter than those of state-of-the-art accelerators optimized for high instantaneous flux. Furthermore, these observations draw ion interaction physics into the field of ultrafast science, opening the opportunity for quantitative comparison with both numerical modelling and the adjacent fields of ultrafast electron and photon interactions in matter.

  6. Picosecond metrology of laser-driven proton bursts.

    PubMed

    Dromey, B; Coughlan, M; Senje, L; Taylor, M; Kuschel, S; Villagomez-Bernabe, B; Stefanuik, R; Nersisyan, G; Stella, L; Kohanoff, J; Borghesi, M; Currell, F; Riley, D; Jung, D; Wahlström, C-G; Lewis, C L S; Zepf, M

    2016-01-01

    Tracking primary radiation-induced processes in matter requires ultrafast sources and high precision timing. While compact laser-driven ion accelerators are seeding the development of novel high instantaneous flux applications, combining the ultrashort ion and laser pulse durations with their inherent synchronicity to trace the real-time evolution of initial damage events has yet to be realized. Here we report on the absolute measurement of proton bursts as short as 3.5±0.7 ps from laser solid target interactions for this purpose. Our results verify that laser-driven ion acceleration can deliver interaction times over a factor of hundred shorter than those of state-of-the-art accelerators optimized for high instantaneous flux. Furthermore, these observations draw ion interaction physics into the field of ultrafast science, opening the opportunity for quantitative comparison with both numerical modelling and the adjacent fields of ultrafast electron and photon interactions in matter. PMID:26861592

  7. Picosecond metrology of laser-driven proton bursts

    PubMed Central

    Dromey, B.; Coughlan, M.; Senje, L.; Taylor, M.; Kuschel, S.; Villagomez-Bernabe, B.; Stefanuik, R.; Nersisyan, G.; Stella, L.; Kohanoff, J.; Borghesi, M.; Currell, F.; Riley, D.; Jung, D.; Wahlström, C.-G.; Lewis, C.L.S.; Zepf, M.

    2016-01-01

    Tracking primary radiation-induced processes in matter requires ultrafast sources and high precision timing. While compact laser-driven ion accelerators are seeding the development of novel high instantaneous flux applications, combining the ultrashort ion and laser pulse durations with their inherent synchronicity to trace the real-time evolution of initial damage events has yet to be realized. Here we report on the absolute measurement of proton bursts as short as 3.5±0.7 ps from laser solid target interactions for this purpose. Our results verify that laser-driven ion acceleration can deliver interaction times over a factor of hundred shorter than those of state-of-the-art accelerators optimized for high instantaneous flux. Furthermore, these observations draw ion interaction physics into the field of ultrafast science, opening the opportunity for quantitative comparison with both numerical modelling and the adjacent fields of ultrafast electron and photon interactions in matter. PMID:26861592

  8. Laser-driven electron acceleration in an inhomogeneous plasma channel

    SciTech Connect

    Zhang, Rong; Cheng, Li-Hong; Xue, Ju-Kui

    2015-12-15

    We study the laser-driven electron acceleration in a transversely inhomogeneous plasma channel. We find that, in inhomogeneous plasma channel, the developing of instability for electron acceleration and the electron energy gain can be controlled by adjusting the laser polarization angle and inhomogeneity of plasma channel. That is, we can short the accelerating length and enhance the energy gain in inhomogeneous plasma channel by adjusting the laser polarization angle and inhomogeneity of the plasma channel.

  9. Nonlinear damage effect in graphene synthesis by C-cluster ion implantation

    SciTech Connect

    Zhang Rui; Zhang Zaodi; Wang Zesong; Wang Shixu; Wang Wei; Fu Dejun; Liu Jiarui

    2012-07-02

    We present few-layer graphene synthesis by negative carbon cluster ion implantation with C{sub 1}, C{sub 2}, and C{sub 4} at energies below 20 keV. The small C-clusters were produced by a source of negative ion by cesium sputtering with medium beam current. We show that the nonlinear effect in cluster-induced damage is favorable for graphene precipitation compared with monomer carbon ions. The nonlinear damage effect in cluster ion implantation shows positive impact on disorder reduction, film uniformity, and the surface smoothness in graphene synthesis.

  10. Space-based laser-driven MHD generator: Feasibility study

    NASA Technical Reports Server (NTRS)

    Choi, S. H.

    1986-01-01

    The feasibility of a laser-driven MHD generator, as a candidate receiver for a space-based laser power transmission system, was investigated. On the basis of reasonable parameters obtained in the literature, a model of the laser-driven MHD generator was developed with the assumptions of a steady, turbulent, two-dimensional flow. These assumptions were based on the continuous and steady generation of plasmas by the exposure of the continuous wave laser beam thus inducing a steady back pressure that enables the medium to flow steadily. The model considered here took the turbulent nature of plasmas into account in the two-dimensional geometry of the generator. For these conditions with the plasma parameters defining the thermal conductivity, viscosity, electrical conductivity for the plasma flow, a generator efficiency of 53.3% was calculated. If turbulent effects and nonequilibrium ionization are taken into account, the efficiency is 43.2%. The study shows that the laser-driven MHD system has potential as a laser power receiver for space applications because of its high energy conversion efficiency, high energy density and relatively simple mechanism as compared to other energy conversion cycles.

  11. Radiobiological study by using laser-driven proton beams

    SciTech Connect

    Yogo, A.; Nishikino, M.; Mori, M.; Ogura, K.; Sagisaka, A.; Orimo, S.; Nishiuchi, M.; Pirozhkov, A. S.; Ikegami, M.; Tampo, M.; Sakaki, H.; Suzuki, M.; Daito, I.; Kiriyama, H.; Okada, H.; Kanazawa, S.; Kondo, S.; Shimomura, T.; Nakai, Y.; Kawachi, T.

    2009-07-25

    Particle acceleration driven by high-intensity laser systems is widely attracting interest as a potential alternative to conventional ion acceleration, including ion accelerator applications to tumor therapy. Recent works have shown that a high intensity laser pulse can produce single proton bunches of a high current and a short pulse duration. This unique feature of laser-ion acceleration can lead to progress in the development of novel ion sources. However, there has been no experimental study of the biological effects of laser-driven ion beams. We describe in this report the first demonstrated irradiation effect of laser-accelerated protons on human lung cancer cells. In-vitro A549 cells are irradiated with a proton dose of 20 Gy, resulting in a distinct formation of gamma-H2AX foci as an indicator of DNA double-strand breaks. This is a pioneering result that points to future investigations of the radiobiological effects of laser-driven ion beams. The laser-driven ion beam is apotential excitation source for time-resolved determination of hydroxyl (OH) radical yield, which will explore relationship between the fundamental chemical reactions of radiation effects and consequent biological processes.

  12. Radiobiological study by using laser-driven proton beams

    NASA Astrophysics Data System (ADS)

    Yogo, A.; Sato, K.; Nishikino, M.; Mori, M.; Teshima, T.; Numasaki, H.; Murakami, M.; Demizu, Y.; Akagi, S.; Nagayama, S.; Ogura, K.; Sagisaka, A.; Orimo, S.; Nishiuchi, M.; Pirozhkov, A. S.; Ikegami, M.; Tampo, M.; Sakaki, H.; Suzuki, M.; Daito, I.; Oishi, Y.; Sugiyama, H.; Kiriyama, H.; Okada, H.; Kanazawa, S.; Kondo, S.; Shimomura, T.; Nakai, Y.; Tanoue, M.; Sugiyama, H.; Sasao, H.; Wakai, D.; Kawachi, T.; Nishimura, H.; Bolton, P. R.; Daido, H.

    2009-07-01

    Particle acceleration driven by high-intensity laser systems is widely attracting interest as a potential alternative to conventional ion acceleration, including ion accelerator applications to tumor therapy. Recent works have shown that a high intensity laser pulse can produce single proton bunches of a high current and a short pulse duration. This unique feature of laser-ion acceleration can lead to progress in the development of novel ion sources. However, there has been no experimental study of the biological effects of laser-driven ion beams. We describe in this report the first demonstrated irradiation effect of laser-accelerated protons on human lung cancer cells. In-vitro A549 cells are irradiated with a proton dose of 20 Gy, resulting in a distinct formation of γ-H2AX foci as an indicator of DNA double-strand breaks. This is a pioneering result that points to future investigations of the radiobiological effects of laser-driven ion beams. The laser-driven ion beam is apotential excitation source for time-resolved determination of hydroxyl (OH) radical yield, which will explore relationship between the fundamental chemical reactions of radiation effects and consequent biological processes.

  13. Evolution of nonlinear optical properties: from gold atomic clusters to plasmonic nanocrystals.

    PubMed

    Philip, Reji; Chantharasupawong, Panit; Qian, Huifeng; Jin, Rongchao; Thomas, Jayan

    2012-09-12

    Atomic clusters of metals are an emerging class of extremely interesting materials occupying the intermediate size regime between atoms and nanoparticles. Here we report the nonlinear optical (NLO) characteristics of ultrasmall, atomically precise clusters of gold, which are smaller than the critical size for electronic energy quantization (∼2 nm). Our studies reveal remarkable features of the distinct evolution of the optical nonlinearity as the clusters progress in size from the nonplasmonic regime to the plasmonic regime. We ascertain that the smallest atomic clusters do not show saturable absorption at the surface plasmon wavelength of larger gold nanocrystals (>2 nm). Consequently, the third-order optical nonlinearity in these ultrasmall gold clusters exhibits a significantly lower threshold for optical power limiting. This limiting efficiency, which is superior to that of plasmonic nanocrystals, is highly beneficial for optical limiting applications. PMID:22845756

  14. Emission characteristics of laser-driven dissipative coupled-cavity systems

    SciTech Connect

    Knap, Michael; Arrigoni, Enrico; Linden, Wolfgang von der; Cole, Jared H.

    2011-02-15

    We consider a laser-driven and dissipative system of two coupled cavities with Jaynes-Cummings nonlinearity. In particular, we investigate both incoherent and coherent laser driving, corresponding to different experimental situations. We employ Arnoldi time evolution as a numerical tool to solve exactly the many-body master equation describing the nonequilibrium quantum system. We evaluate the fluorescence spectrum and the spectrum of the second-order correlation function of the emitted light field. Finally, we relate the measured spectra of the dissipative quantum system to excitations of the corresponding nondissipative quantum system. Our results demonstrate how to interpret spectra obtained from dissipative quantum systems and specify what information is contained therein.

  15. Development of foam-based layered targets for laser-driven ion beam production

    NASA Astrophysics Data System (ADS)

    Prencipe, I.; Sgattoni, A.; Dellasega, D.; Fedeli, L.; Cialfi, L.; Choi, Il Woo; Jong Kim, I.; Janulewicz, K. A.; Kakolee, K. F.; Lee, Hwang Woon; Sung, Jae Hee; Lee, Seong Ku; Nam, Chang Hee; Passoni, M.

    2016-03-01

    We report on the development of foam-based double-layer targets (DLTs) for laser-driven ion acceleration. Foam layers with a density of a few mg cm-3 and controlled thickness in the 8-36 μm range were grown on μm-thick Al foils by pulsed laser deposition (PLD). The DLTs were experimentally investigated by varying the pulse intensity, laser polarisation and target properties. Comparing DLTs with simple Al foils, we observed a systematic enhancement of the maximum and average energies and number of accelerated ions. Maximum energies up to 30 MeV for protons and 130 MeV for C6+ ions were detected. Dedicated three-dimensional particle-in-cell (3D-PIC) simulations were performed considering both uniform and cluster-assembled foams to interpret the effect of the foam nanostructure on the acceleration process.

  16. Cluster Consensus of Nonlinearly Coupled Multi-Agent Systems in Directed Graphs

    NASA Astrophysics Data System (ADS)

    Lu, Xiao-Qing; Francis, Austin; Chen, Shi-Hua

    2010-05-01

    We investigate the cluster consensus problem in directed networks of nonlinearly coupled multi-agent systems by using pinning control. Depending on the community structure generated by the group partition of the underlying digraph, various clusters can be made coherently independent by applying feedback injections to a fraction of the agents. Sufficient conditions for cluster consensus are obtained using algebraic graph theory and matrix theory and some simulations results are included to illustrate the method.

  17. The laser driven particle accelerator project: Theory and experiment

    SciTech Connect

    Plettner, T.; Byer, R.L. Smith, T.I.; Siemann, R.H. Huang, Y.C.

    1999-07-01

    A proof of principle experiment for laser driven electron acceleration from crossed laser beams in a dielectric loaded vacuum is being carried out at Stanford University. We seek to measure a maximum energy gain of about 250 keV for a 30{endash}35 MeV electron beam in one accelerator cell. We use laser pulses of a few picoseconds of duration from a regenerative Ti:sapphire laser amplifier at a wavelength of 800 nm in a laser-electron interaction distance of {approximately}1 mm. {copyright} {ital 1999 American Institute of Physics.}

  18. Fusion Yield Enhancement in Magnetized Laser-Driven Implosions

    NASA Astrophysics Data System (ADS)

    Chang, P. Y.; Fiksel, G.; Hohenberger, M.; Knauer, J. P.; Betti, R.; Marshall, F. J.; Meyerhofer, D. D.; Séguin, F. H.; Petrasso, R. D.

    2011-07-01

    Enhancement of the ion temperature and fusion yield has been observed in magnetized laser-driven inertial confinement fusion implosions on the OMEGA Laser Facility. A spherical CH target with a 10 atm D2 gas fill was imploded in a polar-drive configuration. A magnetic field of 80 kG was embedded in the target and was subsequently trapped and compressed by the imploding conductive plasma. As a result of the hot-spot magnetization, the electron radial heat losses were suppressed and the observed ion temperature and neutron yield were enhanced by 15% and 30%, respectively.

  19. Filamentation Instability of Counterstreaming Laser-Driven Plasmas

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    Filamentation due to the growth of a Weibel-type instability was observed in the interaction of a pair of counterstreaming, ablatively driven plasma flows, in a supersonic, collisionless regime relevant to astrophysical collisionless shocks. The flows were created by irradiating a pair of opposing plastic (CH) foils with 1.8 kJ, 2-ns laser pulses on the OMEGA EP Laser System. Ultrafast laser-driven proton radiography was used to image the Weibel-generated electromagnetic fields. The experimental observations are in good agreement with the analytical theory of the Weibel instability and with particle-in-cell simulations.

  20. Fusion yield enhancement in magnetized laser-driven implosions.

    PubMed

    Chang, P Y; Fiksel, G; Hohenberger, M; Knauer, J P; Betti, R; Marshall, F J; Meyerhofer, D D; Séguin, F H; Petrasso, R D

    2011-07-15

    Enhancement of the ion temperature and fusion yield has been observed in magnetized laser-driven inertial confinement fusion implosions on the OMEGA Laser Facility. A spherical CH target with a 10 atm D2 gas fill was imploded in a polar-drive configuration. A magnetic field of 80 kG was embedded in the target and was subsequently trapped and compressed by the imploding conductive plasma. As a result of the hot-spot magnetization, the electron radial heat losses were suppressed and the observed ion temperature and neutron yield were enhanced by 15% and 30%, respectively. PMID:21838372

  1. Three-Dimensional Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect

    Cowan, B.; /SLAC

    2006-09-07

    We discuss simulated photonic crystal structure designs for laser-driven particle acceleration, focusing on three-dimensional planar structures based on the so-called ''woodpile'' lattice. We describe guiding of a speed-of-light accelerating mode by a defect in the photonic crystal lattice and discuss the properties of this mode, including particle beam dynamics and potential coupling methods for the structure. We also discuss possible materials and power sources for this structure and their effects on performance parameters, as well as possible manufacturing techniques and the required tolerances. In addition we describe the computational technique and possible improvements in numerical modeling that would aid development of photonic crystal structures.

  2. Planar laser-driven ablation model for nonlocalized absorption

    SciTech Connect

    Dahmani, F.; Kerdja, T. )

    1991-05-01

    A model for planar laser-driven ablation is presented. Nonlocalized inverse bremsstrahlung absorption of laser energy at a density {ital n}{sub 1}{lt}{ital n}{sub {ital c}} is assumed. A steady-state solution in the conduction zone is joined to a rarefaction wave in the underdense plasma. The calculations relate all steady-state fluid quantities to only the material, absorbed intensity, and laser wavelength. The theory agrees well with results from a computer hydrodynamics code MEDUSA (Comput. Phys. Commun. {bold 7}, 271 (1974)) and experiments.

  3. Dynamics of Laser-Driven Shock Waves in Solid Targets

    NASA Astrophysics Data System (ADS)

    Aglitskiy, Y.; Karasik, M.; Velikovich, A. L.; Serlin, V.; Weaver, J.; Schmitt, A. J.; Obenschain, S. P.; Grun, J.; Metzler, N.; Zalesak, S. T.; Gardner, J. H.; Oh, J.; Harding, E. C.

    2009-11-01

    Accurate shock timing is a key issue of both indirect- and direct-drive laser fusions. The experiments on the Nike laser at NRL presented here were made possible by improvements in the imaging capability of our monochromatic x-ray diagnostics based on Bragg reflection from spherically curved crystals. Side-on imaging implemented on Nike makes it possible to observe dynamics of the shock wave and ablation front in laser-driven solid targets. We can choose to observe a sequence of 2D images or a continuous time evolution of an image resolved in one spatial dimension. A sequence of 300 ps snapshots taken using vanadium backlighter at 5.2 keV reveals propagation of a shock wave in a solid plastic target. The shape of the shock wave reflects the intensity distribution in the Nike beam. The streak records with continuous time resolution show the x-t trajectory of a laser-driven shock wave in a 10% solid density DVB foam.

  4. Review of laser-driven ion sources and their applications.

    PubMed

    Daido, Hiroyuki; Nishiuchi, Mamiko; Pirozhkov, Alexander S

    2012-05-01

    For many years, laser-driven ion acceleration, mainly proton acceleration, has been proposed and a number of proof-of-principle experiments have been carried out with lasers whose pulse duration was in the nanosecond range. In the 1990s, ion acceleration in a relativistic plasma was demonstrated with ultra-short pulse lasers based on the chirped pulse amplification technique which can provide not only picosecond or femtosecond laser pulse duration, but simultaneously ultra-high peak power of terawatt to petawatt levels. Starting from the year 2000, several groups demonstrated low transverse emittance, tens of MeV proton beams with a conversion efficiency of up to several percent. The laser-accelerated particle beams have a duration of the order of a few picoseconds at the source, an ultra-high peak current and a broad energy spectrum, which make them suitable for many, including several unique, applications. This paper reviews, firstly, the historical background including the early laser-matter interaction studies on energetic ion acceleration relevant to inertial confinement fusion. Secondly, we describe several implemented and proposed mechanisms of proton and/or ion acceleration driven by ultra-short high-intensity lasers. We pay special attention to relatively simple models of several acceleration regimes. The models connect the laser, plasma and proton/ion beam parameters, predicting important features, such as energy spectral shape, optimum conditions and scalings under these conditions for maximum ion energy, conversion efficiency, etc. The models also suggest possible ways to manipulate the proton/ion beams by tailoring the target and irradiation conditions. Thirdly, we review experimental results on proton/ion acceleration, starting with the description of driving lasers. We list experimental results and show general trends of parameter dependences and compare them with the theoretical predictions and simulations. The fourth topic includes a review of

  5. Fast route to nonlinear clustering statistics in modified gravity theories

    NASA Astrophysics Data System (ADS)

    Winther, Hans A.; Ferreira, Pedro G.

    2015-06-01

    We propose a simple and computationally fast method for performing N -body simulations for a large class of modified gravity theories with a screening mechanism such as chameleons, symmetrons, and Galileons. By combining the linear Klein-Gordon equation with a screening factor, calculated from analytical solutions of spherical symmetric configurations, we obtain a modified field equation of which the solution is exact in the linear regime while at the same time taking screening into account on nonlinear scales. The resulting modified field equation remains linear and can be solved just as quickly as the Poisson equation without any of the convergence problems that can arise when solving the full equation. We test our method with N -body simulations and find that it compares remarkably well with full simulations well into the nonlinear regime.

  6. Laser-driven Sisyphus cooling in an optical dipole trap

    SciTech Connect

    Ivanov, Vladyslav V.; Gupta, Subhadeep

    2011-12-15

    We propose a laser-driven Sisyphus-cooling scheme for atoms confined in a far-off resonance optical dipole trap. Utilizing the differential trap-induced ac Stark shift, two electronic levels of the atom are resonantly coupled by a cooling laser preferentially near the trap bottom. After absorption of a cooling photon, the atom loses energy by climbing the steeper potential, and then spontaneously decays preferentially away from the trap bottom. The proposed method is particularly suited to cooling alkaline-earth-metal-like atoms where two-level systems with narrow electronic transitions are present. Numerical simulations for the cases of {sup 88}Sr and {sup 174}Yb demonstrate the expected recoil and Doppler temperature limits. The method requires a relatively small number of scattered photons and can potentially lead to phase-space densities approaching quantum degeneracy in subsecond time scales.

  7. Laser-driven Sisyphus cooling in an optical dipole trap

    NASA Astrophysics Data System (ADS)

    Ivanov, Vladyslav V.; Gupta, Subhadeep

    2011-12-01

    We propose a laser-driven Sisyphus-cooling scheme for atoms confined in a far-off resonance optical dipole trap. Utilizing the differential trap-induced ac Stark shift, two electronic levels of the atom are resonantly coupled by a cooling laser preferentially near the trap bottom. After absorption of a cooling photon, the atom loses energy by climbing the steeper potential, and then spontaneously decays preferentially away from the trap bottom. The proposed method is particularly suited to cooling alkaline-earth-metal-like atoms where two-level systems with narrow electronic transitions are present. Numerical simulations for the cases of 88Sr and 174Yb demonstrate the expected recoil and Doppler temperature limits. The method requires a relatively small number of scattered photons and can potentially lead to phase-space densities approaching quantum degeneracy in subsecond time scales.

  8. Flyer Velocity Characteristics of the Laser-Driven Miniflyer System

    SciTech Connect

    Gehr, R.J.; Harper, R.W.; Robbins, D.L.; Rupp, T.D.; Sheffield, S.A.; Stahl, D.B.

    1999-07-01

    The laser-driven MiniFlyer system is used to launch a small, thin flyer plate for impact on a target. Consequently, it is an indirect drive technique that de-couples the shock from the laser beam profile. The flyer velocity can be controlled by adjustment of the laser energy. The upper limits on the flyer velocity involve the ability of the substrate window to transmit the laser light without absorbing, reflecting, etc.; i.e., a maximum amount of laser energy is directly converted into kinetic energy of the flyer plate. We have investigated the use of sapphire, quartz, and BK-7 glass as substrate windows. In the past, a particular type of sapphire has been used for nearly all MiniFlyer experiments. Results of this study in terms of the performance of these window materials, based on flyer velocity, are discussed.

  9. Compact Couplers for Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect

    Cowan, Benjamin; Lin, M.C.; Schwartz, Brian; Byer, Robert; McGuinness, Christopher; Colby, Eric; England, Robert; Noble, Robert; Spencer, James; /SLAC

    2012-07-02

    Photonic crystal waveguides are promising candidates for laser-driven accelerator structures because of their ability to confine a speed-of-light mode in an all-dielectric structure. Because of the difference between the group velocity of the waveguide mode and the particle bunch velocity, fields must be coupled into the accelerating waveguide at frequent intervals. Therefore efficient, compact couplers are critical to overall accelerator efficiency. We present designs and simulations of high-efficiency coupling to the accelerating mode in a three-dimensional photonic crystal waveguide from a waveguide adjoining it at 90{sup o}. We discuss details of the computation and the resulting transmission. We include some background on the accelerator structure and photonic crystal-based optical acceleration in general.

  10. Laser-driven ICF experiments: Laboratory Report No. 223

    SciTech Connect

    McCrory, R.L.

    1991-04-01

    Laser irradiation uniformity is a key issue and is treated in some detail. The basic irradiation uniformity requirements and practical ways of achieving these requirements are both discussed, along with two beam-smoothing techniques: induced spatial incoherence (ISI), and smoothing by spectral dispersion (SSD). Experiments to measure and control the irradiation uniformity are also highlighted. Following the discussion of irradiation uniformity, a brief review of coronal physics is given, including the basic physical processes and their experimental signatures, together with a summary of pertinent diagnostics and results from experiments. Methods of determining ablation rates and thermal transport are also described. The hydrodynamics of laser-driven targets must be fully understood on the basis of experiments. Results from implosion experiments, including a brief description of the diagnostics, are presented. Future experiments aimed at determining ignition scaling and demonstrating hydrodynamically equivalent physics applicable to high-gain designs.

  11. Laser Driven Shock Experiments for Deuterium EOS Studies

    NASA Astrophysics Data System (ADS)

    Oh, Jaechul; Mostovych, Andrew

    2005-10-01

    With the Nike KrF laser facility at the Naval Research Laboratory, we have conducted laser driven shock experiments along the primary Hugoniot of deuterium in the pressure range 25 ˜ 200 GPa (0.25 ˜ 2 Mbar). A streak camera was used to resolve the optical self-emission from the shocks and provide information about the shock temperatures. A NIST traceable lamp with photomultipliers was used to calibrate in situ the device for the temperature measurements. Velocity interferometer system for any reflector (VISAR) measured the shock speed and the reflectivity at the shock front. The preheat effect on the shock formation is also investigated. The results from these measurements will be presented to evaluate various EOS models. This research was performed in Laser Plasma Branch, Plasma Physics Division, Naval Research Laboratory and was supported by the U.S. Department of Energy.

  12. Towards GeV laser-driven ion acceleration

    NASA Astrophysics Data System (ADS)

    Hegelich, B. M.; Yin, L.; Albright, B. J.; Flippo, K. A.; Gautier, D. C.; Johnson, R. P.; Letzring, S.; Shah, R. C.; Shimada, T.; Fernandez, J. C.; Henig, A.; Kiefer, D.; Liechtenstein, V.; Schreiber, J.; Habs, D.; Meyer-Ter-Vehn, J.; Rykovanov, S.; Wu, H. C.

    2008-11-01

    Applications like ion-driven fast ignition (IFI) with heavy ions or laser-based hadron therapy require efficient laser-driven ion acceleration to ˜ 0.1 -- 1 GeV. The Break-Out Afterburner (BOA) [1] regime and the Phase-Stable Acceleration (PSA) [2] regime, also reported as Radiation Pressure Acceleration (RPA) [3], promise quasi-monoenergetic beams at such energies, with ˜ 10% efficiency,. This talk summarizes our joint exploratory research program in this new and exciting area, emphasizing the realization of these mechanisms with today's lasers. The laser requirements are discussed, especially pulse contrast. The first experimental results are reported. [1] L. Yin et al., Laser & Part. Beams 24, 1-8 (2006) [2] X. Zhang et al., Phys. Plasmas 14, 123108 (2007) [3] A. P. L. Robinson et al., New J. Phys. 10, 013021 (2008)

  13. Characterization of short-pulse laser driven neutron source

    NASA Astrophysics Data System (ADS)

    Falk, Katerina; Jung, Daniel; Guler, Nevzat; Deppert, Oliver; Devlin, Matthew; Fernandez, J. C.; Gautier, D. C.; Geissel, M.; Haight, R. C.; Hegelich, B. M.; Henzlova, Daniela; Ianakiev, K. D.; Iliev, Metodi; Johnson, R. P.; Merrill, F. E.; Schaumann, G.; Schoenberg, K.; Shimada, T.; Taddeucci, T. N.; Tybo, J. L.; Wagner, F.; Wender, S. A.; Wurden, G. A.; Favalli, Andrea; Roth, Markus

    2014-10-01

    We present a full spectral characterization of a novel laser driven neutron source, which employed the Break Out Afterburner ion acceleration mechanism. Neutrons were produced by nuclear reactions of the ions deposited on Be or Cu converters. We observed neutrons at energies up to 150 MeV. The neutron spectra were measured by five neutron time-of-flight detectors at various positions and distances from the source. The nTOF detectors observed that emission of neutrons is a superposition of an isotropic component peaking at 3.5--5 MeV resulting from nuclear reactions in the converter and a directional component at 25--70 MeV, which was a product of break-up reaction of the forward moving deuterons. Energy shifts due to geometrical effects in BOA were also observed.

  14. Ultrafast laser-driven proton sources and dynamic proton imaging

    SciTech Connect

    Nickles, Peter V.; Schnuerer, Matthias; Sokollik, Thomas; Ter-Avetisyan, Sargis; Sandner, Wolfgang; Amin, Munib; Toncian, Toma; Willi, Oswald; Andreev, Alexander

    2008-07-15

    Ion bursts, accelerated by an ultrafast (40 fs) laser-assisted target normal sheath acceleration mechanism, can be adjusted so as to deliver a nearly pure proton beam. Such laser-driven proton bursts have predominantly a low transverse emittance and a broad kinetic spectrum suitable for continuous probing of the temporal evolution of spatially extended electric fields that arise after laser irradiation of thin foils. Fields with a strength of up to 10{sup 10} V/m were measured with a new streaklike proton deflectometry setup. The data show the temporal and spatial evolution of electric fields that are due to target charge-up and ion-front expansion following intense laser-target interaction at intensities of 10{sup 17}-10{sup 18} W/cm{sup 2}. Measurement of the field evolution is important to gain further insight into lateral electron-transport processes and the influence of field dynamics on ion beam properties.

  15. Studies of laser-driven radiative blast waves

    SciTech Connect

    Edwards, M J; Hansen, J; Edens, A; Ditmire, T; Adams, R; Rambo, P; Ruggles, L; Smith, I; Porter, J

    2004-04-29

    We have performed two sets of experiments looking at laser-driven radiating blast waves. In one set of experiments the effect of a drive laser's passage through a background gas on the hydrodynamical evolution of blast waves was examined. It was found that the laser's passage heats a channel in the gas, creating a region where a portion of the blast wave front had an increased velocity, leading to the formation of a bump-like protrusion on the blast wave. The second set of experiments involved the use of regularly spaced wire arrays to induce perturbations on a blast wave surface. The decay of these perturbations as a function of time was measured for various wave number perturbations and found to be in good agreement with theoretical predictions.

  16. NONLINEAR COLOR-METALLICITY RELATIONS OF GLOBULAR CLUSTERS. V. NONLINEAR ABSORPTION-LINE INDEX VERSUS METALLICITY RELATIONS AND BIMODAL INDEX DISTRIBUTIONS OF M31 GLOBULAR CLUSTERS

    SciTech Connect

    Kim, Sooyoung; Yoon, Suk-Jin; Chung, Chul; Lee, Young-Wook; Caldwell, Nelson; Schiavon, Ricardo P.; Kang, Yongbeom; Rey, Soo-Chang

    2013-05-10

    Recent spectroscopy on the globular cluster (GC) system of M31 with unprecedented precision witnessed a clear bimodality in absorption-line index distributions of old GCs. Such division of extragalactic GCs, so far asserted mainly by photometric color bimodality, has been viewed as the presence of merely two distinct metallicity subgroups within individual galaxies and forms a critical backbone of various galaxy formation theories. Given that spectroscopy is a more detailed probe into stellar population than photometry, the discovery of index bimodality may point to the very existence of dual GC populations. However, here we show that the observed spectroscopic dichotomy of M31 GCs emerges due to the nonlinear nature of metallicity-to-index conversion and thus one does not necessarily have to invoke two separate GC subsystems. We take this as a close analogy to the recent view that metallicity-color nonlinearity is primarily responsible for observed GC color bimodality. We also demonstrate that the metallicity-sensitive magnesium line displays non-negligible metallicity-index nonlinearity and Balmer lines show rather strong nonlinearity. This gives rise to bimodal index distributions, which are routinely interpreted as bimodal metallicity distributions, not considering metallicity-index nonlinearity. Our findings give a new insight into the constitution of M31's GC system, which could change much of the current thought on the formation of GC systems and their host galaxies.

  17. Symmetry breaking in ligand-protected gold clusters probed by nonlinear optics.

    PubMed

    Van Steerteghem, Nick; Van Cleuvenbergen, Stijn; Deckers, Steven; Kumara, Chanaka; Dass, Amala; Häkkinen, Hannu; Clays, Koen; Verbiest, Thierry; Knoppe, Stefan

    2016-06-16

    The first hyperpolarizabilities of [Au25(SR)18](-1/0) and Au38(SR)24 clusters were determined by Hyper-Rayleigh Scattering. A strong dependence on the molecular symmetry was observed, and we explore two strategies to destroy the center of inversion in [Au25(SR)18](-1/0), protection by chiral ligands and alloying of the cluster with silver. This may open new avenues to applications of Au : SR clusters in second-order nonlinear optics. PMID:27264025

  18. Symmetry breaking in ligand-protected gold clusters probed by nonlinear optics

    NASA Astrophysics Data System (ADS)

    van Steerteghem, Nick; van Cleuvenbergen, Stijn; Deckers, Steven; Kumara, Chanaka; Dass, Amala; Häkkinen, Hannu; Clays, Koen; Verbiest, Thierry; Knoppe, Stefan

    2016-06-01

    The first hyperpolarizabilities of [Au25(SR)18]-1/0 and Au38(SR)24 clusters were determined by Hyper-Rayleigh Scattering. A strong dependence on the molecular symmetry was observed, and we explore two strategies to destroy the center of inversion in [Au25(SR)18]-1/0, protection by chiral ligands and alloying of the cluster with silver. This may open new avenues to applications of Au : SR clusters in second-order nonlinear optics.The first hyperpolarizabilities of [Au25(SR)18]-1/0 and Au38(SR)24 clusters were determined by Hyper-Rayleigh Scattering. A strong dependence on the molecular symmetry was observed, and we explore two strategies to destroy the center of inversion in [Au25(SR)18]-1/0, protection by chiral ligands and alloying of the cluster with silver. This may open new avenues to applications of Au : SR clusters in second-order nonlinear optics. Electronic supplementary information (ESI) available: Synthesis and characterization of the clusters, details on HRS measurements and DFT calculations. See DOI: 10.1039/c6nr02251k

  19. Optimal control of ultrafast laser driven many-electron dynamics in a polyatomic molecule: N-methyl-6-quinolone

    NASA Astrophysics Data System (ADS)

    Klamroth, Tillmann

    2006-04-01

    We report time-dependent configuration interaction singles calculations for the ultrafast laser driven many-electron dynamics in a polyatomic molecule, N-methyl-6-quinolone. We employ optimal control theory to achieve a nearly state-selective excitation from the S0 to the S1 state, on a time scale of a few (≈6) femtoseconds. The optimal control scheme is shown to correct for effects opposing a state-selective transition, such as multiphoton transitions and other, nonlinear phenomena, which are induced by the ultrashort and intense laser fields. In contrast, simple two-level π pulses are not effective in state-selective excitations when very short pulses are used. Also, the dependence of multiphoton and nonlinear effects on the number of states included in the dynamical simulations is investigated.

  20. SU-D-BRE-05: Feasibility and Limitations of Laser-Driven Proton Therapy: A Treatment Planning Study

    SciTech Connect

    Hofmann, K; Wilkens, J; Masood, U; Pawelke, J

    2014-06-01

    Purpose: Laser-acceleration of particles may offer a cost- and spaceefficient alternative for future radiation therapy with particles. Laser-driven particle beams are pulsed with very short bunch times, and a high number of particles is delivered within one laser shot which cannot be portioned or modulated during irradiation. The goal of this study was to examine whether good treatment plans can be produced for laser-driven proton beams and to investigate the feasibility of a laser-driven treatment unit. Methods: An exponentially decaying proton spectrum was tracked through a gantry and energy selection beam line design to produce multiple proton spectra with different energy widths centered on various nominal energies. These spectra were fed into a treatment planning system to calculate spot scanning proton plans using different lateral widths of the beam and different numbers of protons contained in the initial spectrum. The clinical feasibility of the resulting plans was analyzed in terms of dosimetric quality and the required number of laser shots as an estimation of the overall treatment time. Results: We were able to produce treatment plans with plan qualities of clinical relevance for a maximum initial proton number per laser shot of 6*10{sup 8}. However, the associated minimum number of laser shots was in the order of 10{sup 4}, indicating a long delivery time in the order of at least 15 minutes, when assuming an optimistic repetition rate of the laser system of 10 Hz. Conclusion: With the simulated beam line and the assumed shape of the proton spectrum it was impossible to produce clinically acceptable treatment plans that can be delivered in a reasonable time. The situation can be improved by a method or a device in the beam line which can modulate the number of protons from shot to shot. Supported by DFG Cluster of Excellence: Munich-Centre for Advanced Photonics.

  1. Nonlinear effects of dark energy clustering beyond the acoustic scales

    SciTech Connect

    Anselmi, Stefano; Sefusatti, Emiliano E-mail: dlopez_n@ictp.it

    2014-07-01

    We extend the resummation method of Anselmi and Pietroni (2012) to compute the total density power spectrum in models of quintessence characterized by a vanishing speed of sound. For standard ΛCDM cosmologies, this resummation scheme allows predictions with an accuracy at the few percent level beyond the range of scales where acoustic oscillations are present, therefore comparable to other, common numerical tools. In addition, our theoretical approach indicates an approximate but valuable and simple relation between the power spectra for standard quintessence models and models where scalar field perturbations appear at all scales. This, in turn, provides an educated guess for the prediction of nonlinear growth in models with generic speed of sound, particularly valuable since no numerical results are yet available.

  2. Nonlinear clustering in the CfA redshift survey

    SciTech Connect

    Alimi, J.; Blanchard, A.; Schaeffer, R. Ecole Polytechnique, Palaiseau Paris VII Universite CEA, Service de Physique Theorique de Saclay, Gif-sur-Yvette )

    1990-01-01

    The probability of finding a hole in a randomly placed sphere of volume V has been considered in the Cfa survey by numerous authors. The main emphasis of these studies has been on a scaling law derived from the assumption of hierarchical clustering. Here, the counts in cell statistics P(N) in the CfA redshift survey are analyzed. The results show that the general behavior of the P(N) can be predicted on the sole assumption of the hierarchical hypothesis. Scaling forms can then be predicted which appear to be verified to a fairly good extent in the Cfa redshift survey. This implies that the hypothesis of scale-invariant many-body correlations function provides for a satisfactory description of the count-in-cell statistics. 23 refs.

  3. Laser-driven mechanical fracture in fused silica

    NASA Astrophysics Data System (ADS)

    Dahmani, Faiz

    1999-10-01

    Fused silica, widely used as optical-window material in high-fluence requirements on glass and KrF lasers, experiences optical damage. Under fatigue conditions, the damage is initiated by slow crack growth and culminates, if not arrested, with catastrophic crack growth and implosive failure when the stress intensity approaches the critical value. Since laser-induced cracks cannot be eliminated entirely, the behavior of cracked structures under service conditions must be quantified to be predicted. Systematic scientific rules must be devised to characterize laser-induced cracks and their effects, and to predict if and when it may become necessary to replace the damaged components. This thesis makes a contribution toward this end. Measurements of fatigue failure strength of laser-cracked fused silica in air at room temperature for different number of laser pulses and laser fluences are presented. The failure-strength variability is found to be due mainly to the spectrum of crack depths. Agreement with theory suggests the incorporation of a residual term into the failure-strength equation. Experiments on residual stresses induced in fused silica by the presence of a laser-induced crack are carried out using two different techniques. Theoretical modelings show that this residual stress field is of shear nature and mouth-opening. A correlation between the reduction in fracture strength of fused silica and the increase of the residual-stress field is established, providing laser systems designers and operators with guidance on the rate of crack growth as well as on the stress-related ramifications such as laser-driven cracks entail. Specifically, a hoop-stress in the immediate vicinity of a crack growing along the beam propagation direction is identified as strongly coupling to both the laser fluence and the crack growth. This coupling prompted the question of whether or not breaking the hoop stress symmetry by some external perturbation will accelerate or stymie crack

  4. Synthesis of submicron metastable phase of silicon using femtosecond laser-driven shock wave

    SciTech Connect

    Tsujino, Masashi; Sano, Tomokazu; Sakata, Osami; Ozaki, Norimasa; Kodama, Ryosuke; Kimura, Shigeru; Takeda, Shingo; Kobayashi, Kojiro F.; Hirose, Akio

    2011-12-15

    We measured the grain size of metastable phase of Si synthesized by shock compression. We analyzed the crystalline structures of the femtosecond laser-driven shock compressed silicon with x-ray diffraction measurements. We found that submicron grains of metastable Si-VIII exist in the silicon. We suggest that the pressure loading time is too short for the nucleated high-pressure phases to grow in case of the femtosecond laser-driven shock compression, therefore Si-VIII grains of submicron size are obtained. We are expecting to discover other unique crystalline structures induced by the femtosecond laser-driven shock wave.

  5. Common Visual Pattern Discovery via Nonlinear Mean Shift Clustering.

    PubMed

    Wang, Linbo; Tang, Dong; Guo, Yanwen; Do, Minh N

    2015-12-01

    Discovering common visual patterns (CVPs) from two images is a challenging task due to the geometric and photometric deformations as well as noises and clutters. The problem is generally boiled down to recovering correspondences of local invariant features, and the conventionally addressed by graph-based quadratic optimization approaches, which often suffer from high computational cost. In this paper, we propose an efficient approach by viewing the problem from a novel perspective. In particular, we consider each CVP as a common object in two images with a group of coherently deformed local regions. A geometric space with matrix Lie group structure is constructed by stacking up transformations estimated from initially appearance-matched local interest region pairs. This is followed by a mean shift clustering stage to group together those close transformations in the space. Joining regions associated with transformations of the same group together within each input image forms two large regions sharing similar geometric configuration, which naturally leads to a CVP. To account for the non-Euclidean nature of the matrix Lie group, mean shift vectors are derived in the corresponding Lie algebra vector space with a newly provided effective distance measure. Extensive experiments on single and multiple common object discovery tasks as well as near-duplicate image retrieval verify the robustness and efficiency of the proposed approach. PMID:26415176

  6. Time-dependent quantum chemistry of laser driven many-electron molecules

    SciTech Connect

    Nguyen-Dang, Thanh-Tung; Couture-Bienvenue, Étienne; Viau-Trudel, Jérémy; Sainjon, Amaury

    2014-12-28

    A Time-Dependent Configuration Interaction approach using multiple Feshbach partitionings, corresponding to multiple ionization stages of a laser-driven molecule, has recently been proposed [T.-T. Nguyen-Dang and J. Viau-Trudel, J. Chem. Phys. 139, 244102 (2013)]. To complete this development toward a fully ab-initio method for the calculation of time-dependent electronic wavefunctions of an N-electron molecule, we describe how tools of multiconfiguration quantum chemistry such as the management of the configuration expansion space using Graphical Unitary Group Approach concepts can be profitably adapted to the new context, that of time-resolved electronic dynamics, as opposed to stationary electronic structure. The method is applied to calculate the detailed, sub-cycle electronic dynamics of BeH{sub 2}, treated in a 3–21G bound-orbital basis augmented by a set of orthogonalized plane-waves representing continuum-type orbitals, including its ionization under an intense λ = 800 nm or λ = 80 nm continuous-wave laser field. The dynamics is strongly non-linear at the field-intensity considered (I ≃ 10{sup 15} W/cm{sup 2}), featuring important ionization of an inner-shell electron and strong post-ionization bound-electron dynamics.

  7. Laser-driven relativistic electron beam interaction with solid dielectric

    SciTech Connect

    Sarkisov, G. S.; Ivanov, V. V.; Leblanc, P.; Sentoku, Y.; Yates, K.; Wiewior, P.; Chalyy, O.; Astanovitskiy, A.; Bychenkov, V. Yu.; Jobe, D.; Spielman, R. B.

    2012-07-30

    The multi-frames shadowgraphy, interferometry and polarimetry diagnostics with sub-ps time resolution were used for an investigation of ionization wave dynamics inside a glass target induced by laser-driven relativistic electron beam. Experiments were done using the 50 TW Leopard laser at the UNR. For a laser flux of {approx}2 Multiplication-Sign 10{sup 18}W/cm{sup 2} a hemispherical ionization wave propagates at c/3. The maximum of the electron density inside the glass target is {approx}2 Multiplication-Sign 10{sup 19}cm{sup -3}. Magnetic and electric fields are less than {approx}15 kG and {approx}1 MV/cm, respectively. The electron temperature has a maximum of {approx}0.5 eV. 2D interference phase shift shows the 'fountain effect' of electron beam. The very low ionization inside glass target {approx}0.1% suggests a fast recombination at the sub-ps time scale. 2D PIC-simulations demonstrate radial spreading of fast electrons by self-consistent electrostatic fields.

  8. Quantum Localization in Laser-Driven Molecular Rotation

    NASA Astrophysics Data System (ADS)

    Averbukh, Ilya

    2016-05-01

    Recently we predicted that several celebrated solid state quantum localization phenomena - Anderson localization, Bloch oscillations, and Tamm-Shockley surface states - may manifest themselves in the rotational dynamics of laser-kicked molecules. In this talk, I will present these new rotational effects in a gas of linear molecules subject to a moderately long periodic train of femtosecond laser pulses. A small detuning of the train period from the rotational revival time causes Anderson localization in the angular momentum space above some critical value of J - the Anderson wall. This wall marks an impenetrable border stopping any further rotational excitation. Below the Anderson wall, the rotational excitation oscillates with the number of pulses due to a mechanism similar to Bloch oscillations in crystalline solids. I will present the results of the first experimental observation of the laser-induced rotational Bloch oscillations in molecular nitrogen at ambient conditions (Stanford & Weizmann, 2015). We will also discuss the prospects of observing the rotational analogues of the Tamm surface states in a similar experimental setup. Our results offer laser-driven molecular rotation as a new platform for studies on the localization phenomena in quantum transport. These effects are important for many processes involving highly excited rotational states, including coherent optical manipulations in molecular mixtures, and propagation of powerful laser pulses in atmosphere.

  9. Radiochromic film diagnostics for laser-driven ion beams

    NASA Astrophysics Data System (ADS)

    Kaufman, J.; Margarone, Daniele; Candiano, Giacomo; Kim, I. Jong; Jeong, Tae Moon; Pšikal, Jan; Romano, F.; Cirrone, P.; Scuderi, V.; Korn, Georg

    2015-05-01

    Radiochromic film (RCF) based multichannel diagnostics utilizes the concept of a stack detector comprised of alternating layers of RCFs and shielding aluminium layers. An algorithm based on SRIM simulations is used to correct the accumulated dose. Among the standard information that can be obtained is the maximum ion energy and to some extend the beam energy spectrum. The main area where this detector shines though is the geometrical characterization of the beam. Whereas other detectors such as Thomson parabola spectrometer or Faraday cups detect only a fraction of the outburst cone, the RCF stack placed right behind the target absorbs the whole beam. A complete 2D and to some extend 3D imprint of the ion beam allows us to determine parameters such as divergence or beam center shift with respect to the target normal. The obvious drawback of such diagnostics is its invasive character. But considering that only a few successful shots (2-3) are needed per one kind of target to perform the analysis, the drawbacks are acceptable. In this work, we present results obtained with the RCF diagnostics using both conventional accelerators and laser-driven ion beams during 2 experimental campaigns.

  10. CO2 laser-driven Stirling engine. [space power applications

    NASA Technical Reports Server (NTRS)

    Lee, G.; Perry, R. L.; Carney, B.

    1978-01-01

    A 100-W Beale free-piston Stirling engine was powered remotely by a CO2 laser for long periods of time. The engine ran on both continuous-wave and pulse laser input. The working fluid was helium doped with small quantities of sulfur hexafluoride, SF6. The CO2 radiation was absorbed by the vibrational modes of the sulfur hexafluoride, which in turn transferred the energy to the helium to drive the engine. Electrical energy was obtained from a linear alternator attached to the piston of the engine. Engine pressures, volumes, and temperatures were measured to determine engine performance. It was found that the pulse radiation mode was more efficient than the continuous-wave mode. An analysis of the engine heat consumption indicated that heat losses around the cylinder and the window used to transmit the beam into the engine accounted for nearly half the energy input. The overall efficiency, that is, electrical output to laser input, was approximately 0.75%. However, this experiment was not designed for high efficiency but only to demonstrate the concept of a laser-driven engine. Based on this experiment, the engine could be modified to achieve efficiencies of perhaps 25-30%.

  11. Laser-driven ion acceleration from relativistically transparent nanotargets

    NASA Astrophysics Data System (ADS)

    Hegelich, B. M.; Pomerantz, I.; Yin, L.; Wu, H. C.; Jung, D.; Albright, B. J.; Gautier, D. C.; Letzring, S.; Palaniyappan, S.; Shah, R.; Allinger, K.; Hörlein, R.; Schreiber, J.; Habs, D.; Blakeney, J.; Dyer, G.; Fuller, L.; Gaul, E.; Mccary, E.; Meadows, A. R.; Wang, C.; Ditmire, T.; Fernandez, J. C.

    2013-08-01

    Here we present experimental results on laser-driven ion acceleration from relativistically transparent, overdense plasmas in the break-out afterburner (BOA) regime. Experiments were preformed at the Trident ultra-high contrast laser facility at Los Alamos National Laboratory, and at the Texas Petawatt laser facility, located in the University of Texas at Austin. It is shown that when the target becomes relativistically transparent to the laser, an epoch of dramatic acceleration of ions occurs that lasts until the electron density in the expanding target reduces to the critical density in the non-relativistic limit. For given laser parameters, the optimal target thickness yielding the highest maximum ion energy is one in which this time window for ion acceleration overlaps with the intensity peak of the laser pulse. A simple analytic model of relativistically induced transparency is presented for plasma expansion at the time-evolving sound speed, from which these times may be estimated. The maximum ion energy attainable is controlled by the finite acceleration volume and time over which the BOA acts.

  12. A laser-driven source of polarized hydrogen and deuterium

    SciTech Connect

    Young, L.; Holt, R.J.; Gilman, R.A.; Kowalczyk, R.; Coulter, K.

    1989-01-01

    A novel laser-driven polarized source of hydrogen and deuterium which operates on the principle of spin-exchange optical pumping is being developed. This source is designed to operate as an internal target in an electron storage ring for fundamental studies of spin-dependent structure of nuclei. It has the potential to exceed the flux from existing conventional sources (3 /times/ 10/sup 16//s) by an order of magnitude. Currently, the source delivers hydrogen at a flux of 8 /times/ 10/sup 16/ atoms/s with an atomic polarization of 24% and deuterium at 6 /times/ 10/sup 16/ atoms/s with a polarization of 29%. Technical obstacles which have been overcome, with varying degrees of success are complete Doppler-coverage in the optical-pumping stage without the use of a buffer gas, wall-induced depolarization and radiation-trapping. Future improvements should allow achievement of the design goals of 4 /times/ 10/sup 17/ atoms/s with a polarization of 50%. 8 refs., 2 figs.

  13. Ultra-bright laser-driven neutron source

    NASA Astrophysics Data System (ADS)

    Roth, M.; Favalli, A.; Bagnoud, V.; Bridgewater, J.; Deppert, O.; Devlin, M.; Falk, K.; Fernndez, J.; Gautier, D.; Guler, N.; Henzlova, D.; Hornung, J.; Iliev, M.; Ianakiev, K.; Kleinschmidt, A.; Koehler, K.; Palaniyappan, S.; Poth, P.; Schaumann, G.; Swinhoe, M.; Taddeucci, T.; Tebartz, A.; Wagner, Florian; Wurden, G.

    2015-11-01

    Short-pulse laser-driven neutron sources have become a topic of interest since their brightness and yield have recently increased by orders of magnitude. Using novel target designs, high contrast - high power lasers and compact converter/moderator setups, these neutron sources have finally reached intensities that make many interesting applications possible. We present the results of two experimental campaigns on the GSI PHELIX and the LANL Trident lasers from 2015. We have produced an unprecedented neutron flux, mapped the spatial distribution of the neutron production as well as its energy spectra and ultimately used the beam for first applications to show the prospect of these new compact sources. We also made measurements for the conversion of energetic neutrons into short epithermal and thermal neutron pulses in order to evaluate further applications in dense plasma research. The results address a large community as it paves the way to use short pulse lasers as a neutron source. This can open up neutron research to a broad academic community including material science, biology, medicine and high energy density physics to universities and therefore can complement large scale facilities like reactors or particle accelerators.

  14. Laser-driven relativistic electron beam interaction with solid dielectric

    NASA Astrophysics Data System (ADS)

    Sarkisov, G. S.; Ivanov, V. V.; Leblanc, P.; Sentoku, Y.; Yates, K.; Wiewior, P.; Chalyy, O.; Astanovitskiy, A.; Bychenkov, V. Yu.; Jobe, D.; Spielman, R. B.

    2012-07-01

    The multi-frames shadowgraphy, interferometry and polarimetry diagnostics with sub-ps time resolution were used for an investigation of ionization wave dynamics inside a glass target induced by laser-driven relativistic electron beam. Experiments were done using the 50 TW Leopard laser at the UNR. For a laser flux of ˜2×1018W/cm2 a hemispherical ionization wave propagates at c/3. The maximum of the electron density inside the glass target is ˜2×1019cm-3. Magnetic and electric fields are less than ˜15 kG and ˜1 MV/cm, respectively. The electron temperature has a maximum of ˜0.5 eV. 2D interference phase shift shows the "fountain effect" of electron beam. The very low ionization inside glass target ˜0.1% suggests a fast recombination at the sub-ps time scale. 2D PIC-simulations demonstrate radial spreading of fast electrons by self-consistent electrostatic fields.

  15. Invited Review Article: "Hands-on" laser-driven ion acceleration: A primer for laser-driven source development and potential applications

    NASA Astrophysics Data System (ADS)

    Schreiber, J.; Bolton, P. R.; Parodi, K.

    2016-07-01

    An overview of progress and typical yields from intense laser-plasma acceleration of ions is presented. The evolution of laser-driven ion acceleration at relativistic intensities ushers prospects for improved functionality and diverse applications which can represent a varied assortment of ion beam requirements. This mandates the development of the integrated laser-driven ion accelerator system, the multiple components of which are described. Relevant high field laser-plasma science and design of controlled optimum pulsed laser irradiation on target are dominant single shot (pulse) considerations with aspects that are appropriate to the emerging petawatt era. The pulse energy scaling of maximum ion energies and typical differential spectra obtained over the past two decades provide guidance for continued advancement of laser-driven energetic ion sources and their meaningful applications.

  16. Distributed control of cluster synchronisation in networks with randomly occurring non-linearities

    NASA Astrophysics Data System (ADS)

    Hu, Aihua; Cao, Jinde; Hu, Manfeng; Guo, Liuxiao

    2016-08-01

    This paper is concerned with the issue of mean square cluster synchronisation in complex networks, which consist of non-identical nodes with randomly occurring non-linearities. In order to guarantee synchronisation, distributed controllers depending on the information from the neighbours in the same cluster are applied to each node, meanwhile, the control gains are supposed to be updated according to the given laws. Based on the Lyapunov stability theory, the sufficient synchronisation conditions are derived and proved theoretically. Finally, a numerical example is presented to demonstrate the effectiveness of the results.

  17. Nuclear Material Detection by One-Short-Pulse-Laser-Driven Neutron Source

    SciTech Connect

    Favalli, Andrea; Aymond, F.; Bridgewater, Jon S.; Croft, Stephen; Deppert, O.; Devlin, Matthew James; Falk, Katerina; Fernandez, Juan Carlos; Gautier, Donald Cort; Gonzales, Manuel A.; Goodsell, Alison Victoria; Guler, Nevzat; Hamilton, Christopher Eric; Hegelich, Bjorn Manuel; Henzlova, Daniela; Ianakiev, Kiril Dimitrov; Iliev, Metodi; Johnson, Randall Philip; Jung, Daniel; Kleinschmidt, Annika; Koehler, Katrina Elizabeth; Pomerantz, Ishay; Roth, Markus; Santi, Peter Angelo; Shimada, Tsutomu; Swinhoe, Martyn Thomas; Taddeucci, Terry Nicholas; Wurden, Glen Anthony; Palaniyappan, Sasikumar; McCary, E.

    2015-01-28

    Covered in the PowerPoint presentation are the following areas: Motivation and requirements for active interrogation of nuclear material; laser-driven neutron source; neutron diagnostics; active interrogation of nuclear material; and, conclusions, remarks, and future works.

  18. Enhanced electron yield from laser-driven wakefield acceleration in high-Z gas jets

    NASA Astrophysics Data System (ADS)

    Mirzaie, Mohammad; Hafz, Nasr A. M.; Li, Song; Liu, Feng; He, Fei; Cheng, Ya; Zhang, Jie

    2015-10-01

    An investigation of the electron beam yield (charge) form helium, nitrogen, and neon gas jet plasmas in a typical laser-plasma wakefield acceleration experiment is carried out. The charge measurement is made by imaging the electron beam intensity profile on a fluorescent screen into a charge coupled device which was cross-calibrated with an integrated current transformer. The dependence of electron beam charge on the laser and plasma conditions for the aforementioned gases are studied. We found that laser-driven wakefield acceleration in low Z-gas jet targets usually generates high-quality and well-collimated electron beams with modest yields at the level of 10-100 pC. On the other hand, filamentary electron beams which are observed from high-Z gases at higher densities reached much higher yields. Evidences for cluster formation were clearly observed in the nitrogen gas jet target, where we received the highest electron beam charge of ˜1.7 nC. Those intense electron beams will be beneficial for the applications on the generation of bright X-rays, gamma rays radiations, and energetic positrons via the bremsstrahlung or inverse-scattering processes.

  19. Enhanced electron yield from laser-driven wakefield acceleration in high-Z gas jets

    SciTech Connect

    Mirzaie, Mohammad; Hafz, Nasr A. M. Li, Song; Liu, Feng; Zhang, Jie; He, Fei; Cheng, Ya

    2015-10-15

    An investigation of the electron beam yield (charge) form helium, nitrogen, and neon gas jet plasmas in a typical laser-plasma wakefield acceleration experiment is carried out. The charge measurement is made by imaging the electron beam intensity profile on a fluorescent screen into a charge coupled device which was cross-calibrated with an integrated current transformer. The dependence of electron beam charge on the laser and plasma conditions for the aforementioned gases are studied. We found that laser-driven wakefield acceleration in low Z-gas jet targets usually generates high-quality and well-collimated electron beams with modest yields at the level of 10-100 pC. On the other hand, filamentary electron beams which are observed from high-Z gases at higher densities reached much higher yields. Evidences for cluster formation were clearly observed in the nitrogen gas jet target, where we received the highest electron beam charge of ∼1.7 nC. Those intense electron beams will be beneficial for the applications on the generation of bright X-rays, gamma rays radiations, and energetic positrons via the bremsstrahlung or inverse-scattering processes.

  20. Enhanced electron yield from laser-driven wakefield acceleration in high-Z gas jets.

    PubMed

    Mirzaie, Mohammad; Hafz, Nasr A M; Li, Song; Liu, Feng; He, Fei; Cheng, Ya; Zhang, Jie

    2015-10-01

    An investigation of the electron beam yield (charge) form helium, nitrogen, and neon gas jet plasmas in a typical laser-plasma wakefield acceleration experiment is carried out. The charge measurement is made by imaging the electron beam intensity profile on a fluorescent screen into a charge coupled device which was cross-calibrated with an integrated current transformer. The dependence of electron beam charge on the laser and plasma conditions for the aforementioned gases are studied. We found that laser-driven wakefield acceleration in low Z-gas jet targets usually generates high-quality and well-collimated electron beams with modest yields at the level of 10-100 pC. On the other hand, filamentary electron beams which are observed from high-Z gases at higher densities reached much higher yields. Evidences for cluster formation were clearly observed in the nitrogen gas jet target, where we received the highest electron beam charge of ∼1.7 nC. Those intense electron beams will be beneficial for the applications on the generation of bright X-rays, gamma rays radiations, and energetic positrons via the bremsstrahlung or inverse-scattering processes. PMID:26520950

  1. Nonlinear effects in infrared action spectroscopy of silicon and vanadium oxide clusters: experiment and kinetic modeling.

    PubMed

    Calvo, Florent; Li, Yejun; Kiawi, Denis M; Bakker, Joost M; Parneix, Pascal; Janssens, Ewald

    2015-10-21

    For structural assignment of gas phase compounds, infrared action spectra are usually compared to computed linear absorption spectra. However, action spectroscopy is highly nonlinear owing to the necessary transfer of the excitation energy and its subsequent redistribution leading to statistical ionization or dissociation. Here, we examine by joint experiment and dedicated modeling how such nonlinear effects affect the spectroscopic features in the case of selected inorganic clusters. Vibrational spectra of neutral silicon clusters are recorded by tunable IR-UV two-color ionization while IR spectra for cationic vanadium oxide clusters are obtained by IR multiphoton absorption followed by dissociation of the bare cluster or of its complex with Xe. Our kinetic modeling accounts for vibrational anharmonicities, for the laser interaction through photon absorption and stimulated emission rates, as well as for the relevant ionization or dissociation rates, all based on input parameters from quantum chemical calculations. Comparison of the measured and calculated spectra indicates an overall agreement as far as trends are concerned, except for the photodissociation of the V3O7(+)-Xe messenger complex, for which anharmonicities are too large and poorly captured by the perturbative anharmonic model. In all systems studied, nonlinear effects are essentially manifested by variations in the intensities as well as spectral broadenings. Differences in some band positions originate from inaccuracies of the quantum chemical data rather than specific nonlinear effects. The simulations further yield information on the average number of photons absorbed, which is otherwise unaccessible information: several to several tens of photons need to be absorbed to observe a band through dissociation, while three to five photons can be sufficient for detection of a band via IR-UV ionization. PMID:26208251

  2. Nonlinear management of the angular momentum of soliton clusters: Theory and experiment

    SciTech Connect

    Fratalocchi, Andrea; Piccardi, Armando; Peccianti, Marco; Assanto, Gaetano

    2007-06-15

    We demonstrate, both theoretically and experimentally, how to acquire nonlinear control over the angular momentum of a cluster of solitary waves. Our results, stemming from a universal theoretical model, show that the angular momentum can be adjusted by acting on the global energy input in the system. The phenomenon is experimentally ascertained in nematic liquid crystals by observing a power-dependent rotation of a two-soliton ensemble.

  3. Large-Scale Structure Formation: From the First Non-linear Objects to Massive Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Planelles, S.; Schleicher, D. R. G.; Bykov, A. M.

    2015-05-01

    The large-scale structure of the Universe formed from initially small perturbations in the cosmic density field, leading to galaxy clusters with up to 1015 M⊙ at the present day. Here, we review the formation of structures in the Universe, considering the first primordial galaxies and the most massive galaxy clusters as extreme cases of structure formation where fundamental processes such as gravity, turbulence, cooling and feedback are particularly relevant. The first non-linear objects in the Universe formed in dark matter halos with 105-108 M⊙ at redshifts 10-30, leading to the first stars and massive black holes. At later stages, larger scales became non-linear, leading to the formation of galaxy clusters, the most massive objects in the Universe. We describe here their formation via gravitational processes, including the self-similar scaling relations, as well as the observed deviations from such self-similarity and the related non-gravitational physics (cooling, stellar feedback, AGN). While on intermediate cluster scales the self-similar model is in good agreement with the observations, deviations from such self-similarity are apparent in the core regions, where numerical simulations do not reproduce the current observational results. The latter indicates that the interaction of different feedback processes may not be correctly accounted for in current simulations. Both in the most massive clusters of galaxies as well as during the formation of the first objects in the Universe, turbulent structures and shock waves appear to be common, suggesting them to be ubiquitous in the non-linear regime.

  4. Stimulated scattering in laser driven fusion and high energy density physics experiments

    SciTech Connect

    Yin, L. Albright, B. J.; Rose, H. A.; Montgomery, D. S.; Kline, J. L.; Finnegan, S. M.; Bergen, B.; Bowers, K. J.; Kirkwood, R. K.; Milovich, J.

    2014-09-15

    In laser driven fusion and high energy density physics experiments, one often encounters a kλ{sub D} range of 0.15 < kλ{sub D} < 0.5, where stimulated Raman scattering (SRS) is active (k is the initial electron plasma wave number and λ{sub D} is the Debye length). Using particle-in-cell simulations, the SRS reflectivity is found to scale as ∼ (kλ{sub D}){sup −4} for kλ{sub D} ≳ 0.3 where electron trapping effects dominate SRS saturation; the reflectivity scaling deviates from the above for kλ{sub D} < 0.3 when Langmuir decay instability (LDI) is present. The SRS risk is shown to be highest for kλ{sub D} between 0.2 and 0.3. SRS re-scattering processes are found to be unimportant under conditions relevant to ignition experiments at the National Ignition Facility (NIF). Large-scale simulations of the hohlraum plasma show that the SRS wavelength spectrum peaks below 600 nm, consistent with most measured NIF spectra, and that nonlinear trapping in the presence of plasma gradients determines the SRS spectral peak. Collisional effects on SRS, stimulated Brillouin scattering (SBS), LDI, and re-scatter, together with three dimensional effects, are examined. Effects of collisions are found to include de-trapping as well as cross-speckle electron temperature variation from collisional heating, the latter of which reduces gain, introduces a positive frequency shift that counters the trapping-induced negative frequency shift, and affects SRS and SBS saturation. Bowing and breakup of ion-acoustic wavefronts saturate SBS and cause a dramatic, sharp decrease in SBS reflectivity. Mitigation of SRS and SBS in the strongly nonlinear trapping regime is discussed.

  5. Solid hydrogen target for laser driven proton acceleration

    NASA Astrophysics Data System (ADS)

    Perin, J. P.; Garcia, S.; Chatain, D.; Margarone, D.

    2015-05-01

    The development of very high power lasers opens up new horizons in various fields, such as laser plasma acceleration in Physics and innovative approaches for proton therapy in Medicine. Laser driven proton acceleration is commonly based on the so-called Target Normal Sheath Acceleration (TNSA) mechanisms: a high power laser is focused onto a solid target (thin metallic or plastic foil) and interact with matter at very high intensity, thus generating a plasma; as a consequence "hot" electrons are produced and move into the forward direction through the target. Protons are generated at the target rear side, electrons try to escape from the target and an ultra-strong quasi-electrostatic field (~1TV/m) is generated. Such a field can accelerate protons with a wide energy spectrum (1-200 MeV) in a few tens of micrometers. The proton beam characteristics depend on the laser parameters and on the target geometry and nature. This technique has been validated experimentally in several high power laser facilities by accelerating protons coming from hydrogenated contaminant (mainly water) at the rear of metallic target, however, several research groups are investigating the possibility to perform experiments by using "pure" hydrogen targets. In this context, the low temperature laboratory at CEA-Grenoble has developed a cryostat able to continuously produce a thin hydrogen ribbon (from 40 to 100 microns thick). A new extrusion concept, without any moving part has been carried out, using only the thermodynamic properties of the fluid. First results and perspectives are presented in this paper.

  6. Fiber-coupled laser-driven flyer plates system

    SciTech Connect

    Zhao Xinghai; Zhao Xiang; Gao Yang; Shan Guangcun

    2011-04-15

    A system for the launch of hypervelocity flyer plates has been developed and characterized. Laser-driven flyers were launched from the substrate backed aluminum-alumina-aluminum sandwiched films. A laser-induced plasma is used to drive flyers with typical thickness of 5.5 {mu}m and diameters of less than 1 mm, to achieve velocities of a few km/s. These flyer plates have many applications, from micrometeorite simulation to laser ignition. The flyer plates considered here have up to three layers: an ablation layer, to form plasma; an insulating layer; and a final, thicker layer that forms the final flyer plates. This technique was developed aiming at improving the energy efficiency of the system. The kinetic energy of flyers launched with the additional layer was found to be enhanced by a factor of near 2 (up to 30%). The optical fiber delivery system governs the output spatial profile of the laser spot and power capacity. Moreover, a technique for coupling high-power laser pulses into an optical fiber has been developed. This fiber optic system has been successfully used to launch flyer plates, and the surface finishing quality of the fiber was found to be an important factor. Importantly, measurements of the flyer performance including the mean velocities and planarity were made by an optical time-of-arrival technique using an optical fiber array probe, demonstrating the good planarity of the flyer and the achievable average velocity of 1.7 km/s with approaching 1 mm diameter. Finally, the relationship between flyer velocities and incident laser pulses energy was also investigated.

  7. Simplified laser-driven flyer plates for shock compression science

    SciTech Connect

    Brown, Kathryn E.; Shaw, William L.; Zheng Xianxu; Dlott, Dana D.

    2012-10-15

    We describe a simplified system of laser-driven flyer plates for shock compression science and shock spectroscopy. We used commercially available one-box Nd:YAG lasers and beam homogenization solutions to create two launch systems, one based on a smaller (400 mJ) YAG laser and an inexpensive diffusive optic, and one based on a larger (2500 mJ) laser and a diffractive beam homogenizer. The flyer launch, flight, and impact processes were characterized by an 8 GHz fiberoptic photon Doppler velocimeter. We investigated effects of different substrates, adhesives, absorbers, ablative layers, and punching out disks from continuous foils versus fabricating individual foil disks, and found that a simple metal foil epoxied to a glass window was satisfactory in almost all cases. Our simplified system launched flyer plates with velocities up to 4.5 km s{sup -1} and kinetic energies up to 250 mJ that can drive sustained steady shocks for up to 25 ns. The factor that limits these velocities and energies is the laser fluence that can be transmitted through the glass substrate to the flyer surface without optical damage. Methods to increase this transmission are discussed. Reproducible flyer launches were demonstrated with velocity variations of 0.06% and impact time variations of 1 ns. The usefulness of this flyer plate system is demonstrated by Hugoniot equation of state measurements of a polymer film, emission spectroscopy of a dye embedded in the polymer, and impact initiation and emission spectroscopy of a reactive material consisting of nanoscopic fuel and oxidizer particles.

  8. Hugoniot and spall data from the laser-driven miniflyer

    SciTech Connect

    Warnes, R.H.; Paisley, D.L.; Tonks, D.L.

    1995-09-01

    The laser-driven miniflyer has been developed as a small-sized complement to the propellant or gas-driven gun with which to make material property measurements. Flyer velocities typically range from 0.5 to 1.5 km/s, depending on the energy of the launching laser and the flyer dimensions. The 10--50 {micro}m-thick flyers, 1--3 mm in diameter, and comparably small targets require very little material and are easy to recover for post-experiment analysis. To measure and improve the precision of the measurements, the authors are conducting an extensive series of experiments impacting well-characterized Cu, Al, and Au on several transparent, calibrated, windows (PMMA, LiF, and sapphire). Measurement of the impact and interface velocities with a high-time-resolution velocity interferometer (VISAR) gives them a point on the Hugoniot of the flyer material. These are then compared to published Hugoniot data taken with conventional techniques. In the spall experiments, a flyer strikes a somewhat thicker target of the same material and creates a spall in the target. Measuring the free-surface velocity of the target gives information on the compressive elastic-plastic response of the target to the impact, the tensile spall strength, and the strain rate at which the spall occurred. Volumetric strain rates at spall in these experiments are frequently in the 10{sup 6}--10{sup 8} s{sup {minus}1} range, considerably higher than the 10{sup 3}--10{sup 4} s{sup {minus}1} range obtainable from gas gun experiments.

  9. Syntheses, structures and third-order non-linear optical properties of homometal clusters containing molybdenum

    SciTech Connect

    Li Yong; Lu Jing; Cui Xiaobing; Xu Jiqing . E-mail: xjq@mail.jlu.edu.cn; Li Kechang; Sun Huaying; Li Guanghua; Pan Lingyun; Yang Qingxin

    2005-01-15

    Both the homometal cluster [P(ph{sub 4})]{sub 2}[Mo{sub 2}O{sub 2}({mu}-S){sub 2}(S{sub 2}){sub 2}] (1) and [Mo{sub 2}O{sub 2}({mu}-S){sub 2}(Et{sub 2}dtc){sub 2}] (2) (Et{sub 2}dtc=diethyl-dithiocarbamate) were successfully synthesized by low-temperature solid-state reactions. X-ray single-crystal diffraction studies suggest that compound (1) is a dinuclear anion cluster, and compound (2) is a dinuclear neutral cluster. The two compounds were characterized by elemental analyses, IR spectra and UV-Vis spectra. The third-order non-linear optical (NLO) properties of the clusters were also investigated and all exhibited nice non-linear absorption and self-defocusing performance with moduli of the hyperpolarizabilities 5.145x10{sup -30}esu for (1) and 5.428x10{sup -30}esu for (2)

  10. Non-linear optical properties of gold quantum clusters. The smaller the better.

    PubMed

    Russier-Antoine, Isabelle; Bertorelle, Franck; Vojkovic, Marin; Rayane, Driss; Salmon, Estelle; Jonin, Christian; Dugourd, Philippe; Antoine, Rodolphe; Brevet, Pierre-François

    2014-11-21

    By developing a new method for synthesizing atomically monodisperse Au15 nanoclusters stabilized with glutathione molecules and using the current state-of-the-art methods for synthesizing monodisperse protected Au25 nanoclusters, we investigated their nonlinear optical (NLO) properties after two-photon absorption. The two-photon emission spectra and the first hyperpolarizabilities of these particles were obtained using, in particular, a hyper-Rayleigh scattering technique. The influence on NLO of the excitation wavelength, the size as well as the nature of the ligands is also explored and discussed. Au15, the smallest stable thiolated gold nanocluster, presents remarkable nonlinear properties with respect to two-photon processes. The two-photon absorption cross-section at 780 nm for Au15 is ∼65,700 GM. This experimental cross-section value points to a quantum yield for two-photon emission of about 3 × 10(-7) at 475 nm for Au15. The first hyperpolarizability β for Au15 clusters (509 × 10(-30) esu), as compared to Au25 clusters (128 × 10(-30) esu), is larger considering the difference in the number of gold atoms. Also, 10(30) β per atom values reported for Au15 and Au25 clusters are more than two orders of magnitude larger than the values reported for Au NPs in the size range 10-50 nm, outlining the quantum cluster regime. PMID:25268982

  11. Estimating {Omega} from galaxy redshifts: Linear flow distortions and nonlinear clustering

    SciTech Connect

    Bromley, B.C. |; Warren, M.S.; Zurek, W.H.

    1997-02-01

    We propose a method to determine the cosmic mass density {Omega} from redshift-space distortions induced by large-scale flows in the presence of nonlinear clustering. Nonlinear structures in redshift space, such as fingers of God, can contaminate distortions from linear flows on scales as large as several times the small-scale pairwise velocity dispersion {sigma}{sub {nu}}. Following Peacock & Dodds, we work in the Fourier domain and propose a model to describe the anisotropy in the redshift-space power spectrum; tests with high-resolution numerical data demonstrate that the model is robust for both mass and biased galaxy halos on translinear scales and above. On the basis of this model, we propose an estimator of the linear growth parameter {beta}={Omega}{sup 0.6}/b, where b measures bias, derived from sampling functions that are tuned to eliminate distortions from nonlinear clustering. The measure is tested on the numerical data and found to recover the true value of {beta} to within {approximately}10{percent}. An analysis of {ital IRAS} 1.2 Jy galaxies yields {beta}=0.8{sub {minus}0.3}{sup +0.4} at a scale of 1000kms{sup {minus}1}, which is close to optimal given the shot noise and finite size of the survey. This measurement is consistent with dynamical estimates of {beta} derived from both real-space and redshift-space information. The importance of the method presented here is that nonlinear clustering effects are removed to enable linear correlation anisotropy measurements on scales approaching the translinear regime. We discuss implications for analyses of forthcoming optical redshift surveys in which the dispersion is more than a factor of 2 greater than in the {ital IRAS} data. {copyright} {ital 1997} {ital The American Astronomical Society}

  12. A hypervelocity debris simulating technique with laser driven flyer

    NASA Astrophysics Data System (ADS)

    Tong, J.; Dong, H.; Wang, J.

    Theoretical models suggest that most of the space debris in LEO consist of particles are smaller than 0.5mm. LDEF exposed a total surface area of about 130m 2 for 69 months in the LEO environment. It provided a huge collection of impact data that covers a wide size range of impact crater. Total of 34336 impacts were found on the LDEF surface, of which 27385 impact craters were less than 0.5mm in diameter. The small space debris can cause a gradual degradation of a satellite surfaces, including mechanical damage and contamination generated by impacts. Moreover the small debris may cause greater synergistic effects with AO. AO undercutting of impact damage can further expand the damage areas. This paper describes a new method to simulate small space debris by the laser driven flyer technique. A neodymium-glass pulsed laser was used in this work, capable of up 20 joules in 20 nanoseconds. Tow bonding methods to adhere the aluminum foil to the glass substrate were used. One was a field assisted thermal diffusion bond. The other used silicon oil as the adhesive. In the diffusion bond, the laser is used to vaporize the interface of a aluminum foil diffusively bonded to a glass substrate. The vapor reaches high pressures and then cuts out and accelerates a aluminum disk in the diameter of the periphery of the laser beam. In the second flyer configuration, the silicon oil was vaporized by the laser beam and the expanding gas drove the aluminum disc to the hypervelocity. In our tests, both of methods were successful. In the method of silicon oil adhesion, a 2mm diameter, 60micron thick aluminum disc was accelerated to 3.2km/s. But the velocity data of diffusion bond could not be obtained because the meas uring appliance was improper. The method to measure velocity was very simple and cheap. First, the flight time of a particle was measured with a piezoelectric transducer and a digital oscilloscope. Then attaining the flight time and distance of the particle, its velocity

  13. Nonlinear optical behavior of Li n F (n = 2-5) superalkali clusters.

    PubMed

    Srivastava, Ambrish Kumar; Misra, Neeraj

    2015-12-01

    Hyperlithiated clusters are known for their unusual bonding characteristics and lower ionization potentials. This study reports nonlinear optical (NLO) properties of a series of hyperlithiated clusters, Li n F (n = 2-5) for the first time. The structures of small Li n F (n = 2-5) clusters, obtained using second order Møller-Plesset perturbative method, are found to be stable against eliminations of F, F‾, and LiF. These Li n F species are stabilized by both ionic as well as covalent interactions. Our study shows that Li n F species can be thought of as superalkali-halogen (Li n  - F) clusters but belong to the class of superalkalies themselves. These clusters may also possess alkalide and/or electride characteristics due to excess electrons. The dipole moment, mean polarizability, and hyperpolarizability suggest their significant NLO responses which are explained using the highest occupied molecular orbital surfaces and TD-DFT analysis. The exceptionally large hyperpolarizability of Li2F (~10(5) a.u.) and its electride characteristics are particularly highlighted. This study may guide the researchers in the design of novel materials with significant NLO responses useful for electro-optical applications. Graphical Abstract Li2F superalkali resemble an electride in which the excess electron is pushed out by Li2 (+) moiety, leading to its high hyperpolarizability of order of 10(5) a.u. PMID:26546265

  14. Ultrafast electron microscopy and diffraction with laser-driven field emitters

    NASA Astrophysics Data System (ADS)

    Ropers, Claus

    2015-03-01

    Ultrafast structural dynamics in solids and nanostructures can be investigated by an increasing number of sophisticated electron and x-ray diffraction techniques. Electrons are particularly suited for this purpose, exhibiting high scattering cross-sections and allowing for beam control by versatile electrostatic or magnetic lens systems. The capabilities of time-resolved electron imaging techniques critically depend on the employed source of laser-driven ultrashort electron pulses. Nanoscopic sources offer exceptional possibilities for the generation of electron probe pulses with very short durations and high spatial beam coherence. In this talk, I will discuss recent progress in the development of ultrafast electron microscopy and diffraction based on nanoscopic photocathodes. In particular, we implemented ultrafast low-energy electron diffraction (ULEED) and ultrafast transmission electron microscopy (UTEM) driven by nonlinear photoemission from field emission tips. ULEED enables the study of structural changes with high temporal resolution and ultimate surface sensitivity, at sub-keV electron energies. As a first application of this technique, we studied the structural phase transition in a stripe-like polymer superstructure on freestanding monolayer graphene. An advanced UTEM instrument was realized by custom modifications of a standard transmission electron microscope, leading to electron focal spot sizes in the microscope's sample plane of about 10 nm and electron pulse durations of less than 700 fs. Utilizing these features, we investigate the quantum-coherent interaction between the ultrashort electron pulse and the optical near-field of an illuminated nanostructure. Finally, further applications and prospects of ultrafast electron imaging, diffraction and spectroscopy using nanoscale field emitters will be discussed.

  15. Reconstructing the primordial spectrum of fluctuations of the universe from the observed nonlinear clustering of galaxies

    NASA Technical Reports Server (NTRS)

    Hamilton, A. J. S.; Matthews, Alex; Kumar, P.; Lu, Edward

    1991-01-01

    It was discovered that the nonlinear evolution of the two point correlation function in N-body experiments of galaxy clustering with Omega = 1 appears to be described to good approximation by a simple general formula. The underlying form of the formula is physically motivated, but its detailed representation is obtained empirically by fitting to N-body experiments. In this paper, the formula is presented along with an inverse formula which converts a final, nonlinear correlation function into the initial linear correlation function. The inverse formula is applied to observational data from the CfA, IRAs, and APM galaxy surveys, and the initial spectrum of fluctuations of the universe, if Omega = 1.

  16. Stability and Nonlinear Optical Response of Alkalides that Contain a Completely Encapsulated Superalkali Cluster.

    PubMed

    Sun, Wei-Ming; Li, Ying; Li, Xiang-Hui; Wu, Di; He, Hui-Min; Li, Chun-Yan; Chen, Jing-Hua; Li, Zhi-Ru

    2016-09-01

    Guided by density functional theory (DFT) computations, a new series of superalkali-based alkalides, namely FLi2 (+) (aza222)K(-) , OLi3 (+) (aza222)K(-) , NLi4 (+) (aza222)K(-) , and Li3 (+) (aza222)K(-) were designed with various superalkali clusters embedded into an aza222 cage-complexant. These species possess diverse isomeric structures in which the encapsulated superalkalis preserve their identities and behave as alkali metal atoms. The results show that these novel alkalides possess larger complexation energies and enhanced hyperpolarizabilities (β0 ) compared with alkali-metal-based and previous superalkali-based clusters. Especially, a prominent structural dependence of β0 is observed for these studied compounds. Hence, the geometric factors that affect the nonlinear optical (NLO) response of such alkalides is elucidated in detail in this work. This study not only provides novel candidates for alkalides, it also offers an effective way to enhance the NLO response and stability of alkalides. PMID:27219640

  17. Effect of nonthermal electrons on the shock formation in a laser driven plasma

    SciTech Connect

    Nicolaï, Ph. Feugeas, J.-L.; Nguyen-bui, T.; Tikhonchuk, V.; Batani, D.; Maheut, Y.; Antonelli, L.

    2015-04-15

    In the laser-driven inertial fusion schemes and specifically in the shock ignition concept, non thermal electrons may be generated. By depositing their energy far from the origin, they can significantly modify the target hydrodynamics. It is shown in this paper that these electrons may affect the laser-driven shock formation and its propagation through the target. These changes are induced by the target heating and depend on the electron energy spectrum. Furthermore, results of some passive diagnostic may be misinterpreted, indicating an apparent different pressure.

  18. Laser-driven planar Rayleigh-Taylor instability experiments

    NASA Astrophysics Data System (ADS)

    Glendinning, S. G.; Weber, S. V.; Bell, P.; Dasilva, L. B.; Dixit, S. N.; Henesian, M. A.; Kania, D. R.; Kilkenny, J. D.; Powell, H. T.; Wallace, R. J.; Wegner, P. J.; Knauer, J. P.; Verdon, C. P.

    1992-08-01

    We have performed a series of experiments on the Nova Laser Facility to examine the hydrodynamic behavior of directly driven planar foils with initial perturbations of varying wavelength. The foils were accelerated with a single, frequency doubled, smoothed and temporally shaped laser beam at 0.8×1014 W/cm2. The experiments are in good agreement with numerical simulations using the computer codes LASNEX and ORCHID which show growth rates reduced to about 70% of classical for this nonlinear regime.

  19. Structure Loaded Vacuum Laser-Driven Particle Acceleration Experiments at SLAC

    SciTech Connect

    Plettner, T.; Byer, R.L.; Colby, E.R.; Cowan, B.M.; Ischebeck, R.; McGuinness, C.; Lincoln, M.R.; Sears, C.M.; Siemann, R.H.; Spencer, J.E.; /SLAC /Stanford U., Phys. Dept.

    2007-04-09

    We present an overview of the future laser-driven particle acceleration experiments. These will be carried out at the E163 facility at SLAC. Our objectives include a reconfirmation of the proof-of-principle experiment, a staged buncher laser-accelerator experiment, and longer-term future experiments that employ dielectric laser-accelerator microstructures.

  20. Application of a locally optimized control theory to pump dump laser-driven chemical reactions

    NASA Astrophysics Data System (ADS)

    Ohtsuki, Y.; Yahata, Y.; Kono, H.; Fujimura, Y.

    1998-05-01

    A locally optimized control theory is developed. This theory is applied to pump-dump laser-driven chemical reactions via an electronically excited state. The results show that the theory can design the pulse shapes for chemical reactions with high quantum yields in strong laser intensity regimes in which perturbative treatments break down.

  1. Calculation of Coupling Efficiencies for Laser-Driven Photonic Bandgap Structures

    SciTech Connect

    England, R. J.; Ng, C.; Noble, R.; Spencer, J. E.

    2010-11-04

    We present a technique for calculating the power coupling efficiency for a laser-driven photonic bandgap structure using electromagnetic finite element simulations, and evaluate the efficiency of several coupling scenarios for the case of a hollow-core photonic bandgap fiber accelerator structure.

  2. Active Interrogation of Sensitive Nuclear Material Using Laser Driven Neutron Beams

    SciTech Connect

    Favalli, Andrea; Roth, Markus

    2015-05-01

    An investigation of the viability of a laser-driven neutron source for active interrogation is reported. The need is for a fast, movable, operationally safe neutron source which is energy tunable and has high-intensity, directional neutron production. Reasons for the choice of neutrons and lasers are set forth. Results from the interrogation of an enriched U sample are shown.

  3. Pump probe based Raman spectroscopic studies of PTFE under laser driven shock compression

    NASA Astrophysics Data System (ADS)

    Rastogi, Vinay; Rao, Usha; Chaurasia, S.; Mishra, A. K.; Poswal, H. K.; Deo, M. N.; Sharma, S. M.

    2016-05-01

    High pressure spontaneous Raman spectroscopic studies of poly tetra fluro ethylene (PTFE) have been carried out under laser driven shock compression in confinement geometry target. The Raman modes under shock compression as a function of pressure were measured and compared with the corresponding Raman modes in static pressure experiments. Our results indicate that PTFE undergoes transition to phase III across this pressure.

  4. Near-resonance-Rayleigh scattering measurement on a resonant laser-driven barium plasma

    SciTech Connect

    Nee, T.A.

    1985-06-01

    Near-resonance-Rayleigh scattering is used as a space-time-resolved density probe on a resonant laser-driven barium plasma. Feasibility of this technique was investigated. Comparison to other methods such as absorption technique is made and found to be consistent.

  5. Impulse Characteristics of Laser-driven In-Tube Accelerator (LITA)

    SciTech Connect

    Ohtani, Toshiro; Mori, Koichi; Sasoh, Akihiro

    2006-05-02

    In this study, impulse generation processes induced by a single laser pulse in the laser-driven in-tube accelerator are studied through pressure history measured at the center of the projectile base, which acts also as a parabolic mirror. The effects of the fill pressure, laser energy and length of a shroud are analyzed.

  6. Impulse Characteristics of Laser-driven In-Tube Accelerator (LITA)

    NASA Astrophysics Data System (ADS)

    Ohtani, Toshiro; Mori, Koichi; Sasoh, Akihiro

    2006-05-01

    In this study, impulse generation processes induced by a single laser pulse in the laser-driven in-tube accelerator are studied through pressure history measured at the center of the projectile base, which acts also as a parabolic mirror. The effects of the fill pressure, laser energy and length of a shroud are analyzed.

  7. Laser-driven planar Rayleigh-Taylor instability experiments

    SciTech Connect

    Glendinning, S.G.; Weber, S.V.; Bell, P.; DaSilva, L.B.; Dixit, S.N.; Henesian, M.A.; Kania, D.R.; Kilkenny, J.D.; Powell, H.T.; Wallace, R.J.; Wegner, P.J. ); Knauer, J.P.; Verdon, C.P. )

    1992-08-24

    We have performed a series of experiments on the Nova Laser Facility to examine the hydrodynamic behavior of directly driven planar foils with initial perturbations of varying wavelength. The foils were accelerated with a single, frequency doubled, smoothed and temporally shaped laser beam at 0.8{times}10{sup 14} W/cm{sup 2}. The experiments are in good agreement with numerical simulations using the computer codes LASNEX and ORCHID which show growth rates reduced to about 70% of classical for this nonlinear regime.

  8. An efficient, selective collisional ejection mechanism for inner-shell population inversion in laser-driven plasmas

    SciTech Connect

    SCHROEDER,W. ANDREAS; NELSON,THOMAS R.; BORISOV,A.B.; LONGWORTH,J.W.; BOYER,K.; RHODES,C.K.

    2000-06-07

    A theoretical analysis of laser-driven collisional ejection of inner-shell electrons is presented to explain the previously observed anomalous kilovolt L-shell x-ray emission spectra from atomic Xe cluster targets excited by intense sub-picosecond 248nrn ultraviolet radiation. For incident ponderomotively-driven electrons photoionized by strong above threshold ionization, the collisional ejection mechanism is shown to be highly l-state and significantly n-state (i.e. radially) selective for time periods shorter than the collisional dephasing time of the photoionized electronic wavefunction. The resulting preference for the collisional ejection of 2p electrons by an ionized 4p state produces the measured anomalous Xe(L) emission which contains direct evidence for (i) the generation of Xe{sup 27+}(2p{sup 5}3d{sup 10}) and Xe{sup 28+}(2p{sup 5}3d{sup 9}) ions exhibiting inner-shell population inversion and (ii) a coherent correlated electron state collision responsible for the production of double 2p vacancies. For longer time periods, the selectivity of this coherent impact ionization mechanism is rapidly reduced by the combined effects of intrinsic quantum mechanical spreading and dephasing--in agreement with the experimentally observed and extremely strong {minus}{lambda}{sup {minus}6} pump-laser wavelength dependence of the efficiency of inner-shell (2p) vacancy production in Xe clusters excited in underdense plasmas.

  9. Physics of Laser-driven plasma-based acceleration

    SciTech Connect

    Esarey, Eric; Schroeder, Carl B.

    2003-06-30

    The physics of plasma-based accelerators driven by short-pulse lasers is reviewed. This includes the laser wake-field accelerator, the plasma beat wave accelerator, the self-modulated laser wake-field accelerator, and plasma waves driven by multiple laser pulses. The properties of linear and nonlinear plasma waves are discussed, as well as electron acceleration in plasma waves. Methods for injecting and trapping plasma electrons in plasma waves are also discussed. Limits to the electron energy gain are summarized, including laser pulse direction, electron dephasing, laser pulse energy depletion, as well as beam loading limitations. The basic physics of laser pulse evolution in underdense plasmas is also reviewed. This includes the propagation, self-focusing, and guiding of laser pulses in uniform plasmas and plasmas with preformed density channels. Instabilities relevant to intense short-pulse laser-plasma interactions, such as Raman, self-modulation, and hose instabilities, are discussed. Recent experimental results are summarized.

  10. Determination of meso-scale magnetotail structure using Cluster Data and nonlinear dynamics modeling

    NASA Astrophysics Data System (ADS)

    Holland, D. L.; Martin, R. F.; Fioretto, M.; Brennan, C.

    2013-12-01

    A commonly used approximation for the quiet-time magnetotail structure is the modified Harris magnetic field, B =B0[tanh(z/δ)ex + bzez] where B0 is the magnetic field strength far from the sheet, δ is the scale length of the current sheet thickness and bz is the ratio of the magnitude of the field at the midplane to the asymptotic field. Theory and simulations using the modified Harris model have predicted the existence of a signature of nonlinear charged particle dynamics that manifests itself a series of peaks in the ion distribution function. The separation of the peaks has been shown to scale as the fourth root of the normalized ion energy which in turn depends on the combination of parameters σ= bz2 δ. By measuring the location of the peaks in the ion distribution function or differential particle flux we may obtain a measured value for σ, however, we still need an independent measurement of either bz or δ to determine the meso-scale current sheet structure. Using a single spacecraft, precise measurement of either parameter is difficult. The current sheet scale length is problematic since relative motion of the spacecraft and the current sheet cannot be decoupled. This difficulty may be overcome using multiple satellites such as the Cluster mission. Even with multiple spacecrafts, however, the value of the field ratio bz is still difficult to ascertain since it is a small quantity and even a small tilt to the current sheet can result in significant percentage errors. In this paper, we present a statistical analysis of the current sheet structure using Cluster FGM data to determine the current sheet thickness and pitch angle resolved ion distribution function data from the Cluster HIA instrument to determine the value of σ and hence bz. We show that the measurements are in good agreement with those using other techniques, but with a significantly lower uncertainty.

  11. Nonlinear optical characterization of cluster dynamic in water in oil microemulsion by a pump probe laser beam technique

    NASA Astrophysics Data System (ADS)

    Vicari, L.

    2002-11-01

    We present a new pump probe laser beams configuration for the nonlinear optical characterization of microemulsions. We detect the variation of the on-axis optical intensity of the probe beam as generated by the concentration profile induced in an optically thin film of microemulsion by the pump beam. A mathematical model has been introduced to describe the phenomenon. The technique allows the determination of both Kerr-like optical nonlinearity and time constants and, therefore, it gives information both on cluster dimension and their shape. We discuss its application to WAD (water/AOT/decane, where AOT denotes sodium-bis-di-ethyl-sulfosuccinate) with the application of a strong electric field of optical source. Comparison between theoretical predictions and experimental results confirms the presence of giant optical nonlinearity in the absence of turbidity divergence. Chainlike shape of clusters, of the kind already reported with the application of strong electric field, could justify this result.

  12. Nonlinear optical characterization of cluster dynamic in water in oil microemulsion by a pump probe laser beam technique.

    PubMed

    Vicari, L

    2002-11-01

    We present a new pump probe laser beams configuration for the nonlinear optical characterization of microemulsions. We detect the variation of the on-axis optical intensity of the probe beam as generated by the concentration profile induced in an optically thin film of microemulsion by the pump beam. A mathematical model has been introduced to describe the phenomenon. The technique allows the determination of both Kerr-like optical nonlinearity and time constants and, therefore, it gives information both on cluster dimension and their shape. We discuss its application to WAD (water/AOT/decane, where AOT denotes sodium-bis-di-ethyl-sulfosuccinate) with the application of a strong electric field of optical source. Comparison between theoretical predictions and experimental results confirms the presence of giant optical nonlinearity in the absence of turbidity divergence. Chainlike shape of clusters, of the kind already reported with the application of strong electric field, could justify this result. PMID:15010903

  13. Nonlinear optical properties of the inorganic metal cluster MO2Ag4S8(PPh3)4

    NASA Astrophysics Data System (ADS)

    Xia, Tie J.; Dogariu, Aristide C.; Mansour, Kamjou; Hagan, David J.; Said, Ali A.; Van Stryland, Eric W.; Shi, Shu

    1996-10-01

    We describe a series of experiments on solutions of the inorganic metal cluster molecules Mo2Ag4S8(PPh3)4 and compare them with data on a suspension of carbon particles in liquid (ink). The optical limiting behavior is measured using both single picosecond 532 nm pulses and nanosecond long trains of these picosecond pulses. Both materials show reduced transmittance for increasing fluence (energy per unit area). We also perform picosecond time-resolved pump-probe measurements. We find that the observed pump-probe data is nearly identical for the metal cluster solution and the carbon particle suspension (CBS), and we conclude that the nonlinear mechanisms are the same for the two materials. Our previous studies have shown that the nonlinear losses are due to scattering and absorption by microplasmas formed after thermionic emission from heated particles of carbon or inorganic clusters.

  14. Characteristics of laser-driven electron acceleration invacuum

    SciTech Connect

    Wang, P.X.; Ho, Y.K.; Yuan, X.Q.; Kong, Q.; Sessler, A.M.; Esarey, E.; Moshkovich, E.; Nishida, Y.; Yugami, N.; Ito, H.; Wang, J.X.; Scheid, S.

    2001-11-01

    The interaction of free electrons with intense laser beamsin vacuum is studied using a 3D test particle simulation model thatsolves the relativistic Newton-Lorentz equations of motion inanalytically specified laser fields. Recently, a group of solutions wasfound for very intense laser fields that show interesting and unusualcharacteristics. In particular, it was found that an electron can becaptured within the high-intensity laser region, rather than expelledfrom it, and the captured electron can be accelerated to GeV energieswith acceleration gradients on the order of tens of GeV/cm. Thisphenomenon is termed the capture and acceleration scenario (CAS) and isstudied in detail in this paper. The maximum net energy exchange by theCAS mechanism is found to be approximately proportional to a 2_o, in theregime where a_o>100, where a_o = eE_o/m_ewc is a dimensionlessparameter specifying the magnitude of the laser field. The acceleratedGeV electron bunch is a macro-pulse, with duration equal or less thanthat of the laser pulse, which is composed of many micro-pulses that areperiodic at the laser frequency. The energy spectrum of the CAS electronbunch is presented. The dependence of the energy exchange in the CAS onvarious parameters, e.g., a 2_o (laser intensity), w_o (laser radius atfocus), tao (laser pulse duration), b_o (the impact parameter), andtheta_i (the injection angle with respect to the laser propagationdirection), are explored in detail. A comparison with diverse theoreticalmodels is also presented, including a classical model based on phasevelocities and a quantum model based on nonlinear Comptonscattering.

  15. Laser-driven electron beam and radiation sources for basic, medical and industrial sciences

    PubMed Central

    NAKAJIMA, Kazuhisa

    2015-01-01

    To date active research on laser-driven plasma-based accelerators have achieved great progress on production of high-energy, high-quality electron and photon beams in a compact scale. Such laser plasma accelerators have been envisaged bringing a wide range of applications in basic, medical and industrial sciences. Here inheriting the groundbreaker’s review article on “Laser Acceleration and its future” [Toshiki Tajima, (2010)],1) we would like to review recent progress of producing such electron beams due to relativistic laser-plasma interactions followed by laser wakefield acceleration and lead to the scaling formulas that are useful to design laser plasma accelerators with controllability of beam energy and charge. Lastly specific examples of such laser-driven electron/photon beam sources are illustrated. PMID:26062737

  16. Characterization of a novel, short pulse laser-driven neutron sourcea)

    NASA Astrophysics Data System (ADS)

    Jung, D.; Falk, K.; Guler, N.; Deppert, O.; Devlin, M.; Favalli, A.; Fernandez, J. C.; Gautier, D. C.; Geissel, M.; Haight, R.; Hamilton, C. E.; Hegelich, B. M.; Johnson, R. P.; Merrill, F.; Schaumann, G.; Schoenberg, K.; Schollmeier, M.; Shimada, T.; Taddeucci, T.; Tybo, J. L.; Wender, S. A.; Wilde, C. H.; Wurden, G. A.; Roth, M.

    2013-05-01

    We present a full characterization of a short pulse laser-driven neutron source. Neutrons are produced by nuclear reactions of laser-driven ions deposited in a secondary target. The emission of neutrons is a superposition of an isotropic component into 4π and a forward directed, jet-like contribution, with energies ranging up to 80 MeV. A maximum flux of 4.4 × 109 neutrons/sr has been observed and used for fast neutron radiography. On-shot characterization of the ion driver and neutron beam has been done with a variety of different diagnostics, including particle detectors, nuclear reaction, and time-of-flight methods. The results are of great value for future optimization of this novel technique and implementation in advanced applications.

  17. Characterization of a novel, short pulse laser-driven neutron source

    SciTech Connect

    Jung, D.; Falk, K.; Guler, N.; Devlin, M.; Favalli, A.; Fernandez, J. C.; Gautier, D. C.; Haight, R.; Hamilton, C. E.; Hegelich, B. M.; Johnson, R. P.; Merrill, F.; Schoenberg, K.; Shimada, T.; Taddeucci, T.; Tybo, J. L.; Wender, S. A.; Wilde, C. H.; Wurden, G. A.; Deppert, O.; and others

    2013-05-15

    We present a full characterization of a short pulse laser-driven neutron source. Neutrons are produced by nuclear reactions of laser-driven ions deposited in a secondary target. The emission of neutrons is a superposition of an isotropic component into 4π and a forward directed, jet-like contribution, with energies ranging up to 80 MeV. A maximum flux of 4.4 × 10{sup 9} neutrons/sr has been observed and used for fast neutron radiography. On-shot characterization of the ion driver and neutron beam has been done with a variety of different diagnostics, including particle detectors, nuclear reaction, and time-of-flight methods. The results are of great value for future optimization of this novel technique and implementation in advanced applications.

  18. Modeling beam-driven and laser-driven plasma Wakefield accelerators with XOOPIC

    SciTech Connect

    Bruhwiler, David L.; Giacone, Rodolfo; Cary, John R.; Verboncoeur, John P.; Mardahl, Peter; Esarey, Eric; Leemans, Wim

    2000-06-01

    We present 2-D particle-in-cell simulations of both beam-driven and laser-driven plasma wakefield accelerators, using the object-oriented code XOOPIC, which is time explicit, fully electromagnetic, and capable of running on massively parallel supercomputers. Simulations of laser-driven wakefields with low ({approximately} 10{sup 16} W/cm{sup 2}) and high ({approximately} 10{sup 18} W/cm{sup 2}) peak intensity laser pulses are conducted in slab geometry, showing agreement with theory. Simulations of the E-157 beam wakefield experiment at the Stanford Linear Accelerator Center, in which a 30 GeV electron beam passes through 1 m of preionized lithium plasma, are conducted in cylindrical geometry, obtaining good agreement with previous work. We briefly describe some of the more significant modifications to XOOPIC required by this work, and summarize the issues relevant to modeling electron-neutral collisions in a particle-in-cell code.

  19. Intense laser driven collision-less shock and ion acceleration in magnetized plasmas

    NASA Astrophysics Data System (ADS)

    Mima, K.; Jia, Q.; Cai, H. B.; Taguchi, T.; Nagatomo, H.; Sanz, J. R.; Honrubia, J.

    2016-05-01

    The generation of strong magnetic field with a laser driven coil has been demonstrated by many experiments. It is applicable to the magnetized fast ignition (MFI), the collision-less shock in the astrophysics and the ion shock acceleration. In this paper, the longitudinal magnetic field effect on the shock wave driven by the radiation pressure of an intense short pulse laser is investigated by theory and simulations. The transition of a laminar shock (electro static shock) to the turbulent shock (electromagnetic shock) occurs, when the external magnetic field is applied in near relativistic cut-off density plasmas. This transition leads to the enhancement of conversion of the laser energy into high energy ions. The enhancement of the conversion efficiency is important for the ion driven fast ignition and the laser driven neutron source. It is found that the total number of ions reflected by the shock increases by six time when the magnetic field is applied.

  20. Guided post-acceleration of laser-driven ions by a miniature modular structure

    NASA Astrophysics Data System (ADS)

    Kar, Satyabrata; Ahmed, Hamad; Prasad, Rajendra; Cerchez, Mirela; Brauckmann, Stephanie; Aurand, Bastian; Cantono, Giada; Hadjisolomou, Prokopis; Lewis, Ciaran L. S.; Macchi, Andrea; Nersisyan, Gagik; Robinson, Alexander P. L.; Schroer, Anna M.; Swantusch, Marco; Zepf, Matt; Willi, Oswald; Borghesi, Marco

    2016-04-01

    All-optical approaches to particle acceleration are currently attracting a significant research effort internationally. Although characterized by exceptional transverse and longitudinal emittance, laser-driven ion beams currently have limitations in terms of peak ion energy, bandwidth of the energy spectrum and beam divergence. Here we introduce the concept of a versatile, miniature linear accelerating module, which, by employing laser-excited electromagnetic pulses directed along a helical path surrounding the laser-accelerated ion beams, addresses these shortcomings simultaneously. In a proof-of-principle experiment on a university-scale system, we demonstrate post-acceleration of laser-driven protons from a flat foil at a rate of 0.5 GeV m-1, already beyond what can be sustained by conventional accelerator technologies, with dynamic beam collimation and energy selection. These results open up new opportunities for the development of extremely compact and cost-effective ion accelerators for both established and innovative applications.

  1. Study of shockwave method for diagnosing the radiation fields of laser-driven gold hohlraums

    NASA Astrophysics Data System (ADS)

    Li, Yongsheng; Lan, Ke; Huo, Wenyi; Lai, Dongxian; Gao, Yaoming; Pei, Wenbing

    2013-11-01

    Besides the routinely used broad-band x-ray spectrometer (Dante or SXS), ablative shock-wave method is often used to diagnose the radiation fields of laser-driven Hohlraums. The x-ray ablation process of Aluminum and Titanium is studied numerically with a 1-D radiation hydrodynamic code RDMG [F. Tinggui et al., Chin. J. Comput. Phys. 16, 199 (1999)], based on which a new scaling relation of the equivalent radiation temperature with the ablative shock velocity in Aluminum plates is proposed, and a novel method is developed for determining simultaneously the radiation temperature and the M-band (2-4 keV) fraction in laser-driven gold Hohlraums.

  2. Laser-driven electron beam and radiation sources for basic, medical and industrial sciences.

    PubMed

    Nakajima, Kazuhisa

    2015-01-01

    To date active research on laser-driven plasma-based accelerators have achieved great progress on production of high-energy, high-quality electron and photon beams in a compact scale. Such laser plasma accelerators have been envisaged bringing a wide range of applications in basic, medical and industrial sciences. Here inheriting the groundbreaker's review article on "Laser Acceleration and its future" [Toshiki Tajima, (2010)],(1)) we would like to review recent progress of producing such electron beams due to relativistic laser-plasma interactions followed by laser wakefield acceleration and lead to the scaling formulas that are useful to design laser plasma accelerators with controllability of beam energy and charge. Lastly specific examples of such laser-driven electron/photon beam sources are illustrated. PMID:26062737

  3. An online, energy-resolving beam profile detector for laser-driven proton beams.

    PubMed

    Metzkes, J; Zeil, K; Kraft, S D; Karsch, L; Sobiella, M; Rehwald, M; Obst, L; Schlenvoigt, H-P; Schramm, U

    2016-08-01

    In this paper, a scintillator-based online beam profile detector for the characterization of laser-driven proton beams is presented. Using a pixelated matrix with varying absorber thicknesses, the proton beam is spatially resolved in two dimensions and simultaneously energy-resolved. A thin plastic scintillator placed behind the absorber and read out by a CCD camera is used as the active detector material. The spatial detector resolution reaches down to ∼4 mm and the detector can resolve proton beam profiles for up to 9 proton threshold energies. With these detector design parameters, the spatial characteristics of the proton distribution and its cut-off energy can be analyzed online and on-shot under vacuum conditions. The paper discusses the detector design, its characterization and calibration at a conventional proton source, as well as the first detector application at a laser-driven proton source. PMID:27587116

  4. Absolute equation of state measurements of iron using laser driven shocks

    NASA Astrophysics Data System (ADS)

    Benuzzi-Mounaix, A.; Koenig, M.; Huser, G.; Faral, B.; Batani, D.; Henry, E.; Tomasini, M.; Marchet, B.; Hall, T. A.; Boustie, M.; de Rességuier, Th.; Hallouin, M.; Guyot, F.; Andrault, D.; Charpin, Th.

    2002-06-01

    First absolute equation of state measurements obtained for iron with laser driven shock waves are presented. The shock velocity and the free surface velocity of compressed iron have been simultaneously measured by using a VISAR diagnostic, and step targets. The pressure range 1-8 Mbar has been investigated, which is directly relevant to planetary physics. The experiments have been performed at the Laboratoire pour l'Utilisation des Lasers Intenses of the Ecole Polytechnique.

  5. A Laser-Driven Linear Collider: Sample Machine Parameters and Configuration

    SciTech Connect

    Colby, E.R.; England, R.J.; Noble, R.J.; /SLAC

    2011-05-20

    We present a design concept for an e{sup +}e{sup -} linear collider based on laser-driven dielectric accelerator structures, and discuss technical issues that must be addressed to realize such a concept. With a pulse structure that is quasi-CW, dielectric laser accelerators potentially offer reduced beamstrahlung and pair production, reduced event pileup, and much cleaner environment for high energy physics and. For multi-TeV colliders, these advantages become significant.

  6. Measuring high pressure equation of state of polystyrene using laser driven shock wave

    NASA Astrophysics Data System (ADS)

    Shu, Hua; Huang, Xiuguang; Ye, Junjian; Wu, Jiang; Jia, Guo; Fang, Zhiheng; Xie, Zhiyong; Zhou, Huazhen; Fu, Sizu

    2015-11-01

    High precision polystyrene equation of state data were measured using laser-driven shock waves with pressures from 180 GPa to 700 GPa. α quartz was used as standard material, the shock wave trajectory in quartz and polystyrene was measured using the Velocity Interferometer for Any Reflector (VISAR). Instantaneous shock velocity in quartz and polystyrene was obtained when the shock wave pass the interface. This provided ~1% precision in shock velocity measurements.

  7. High Brightness, Laser-Driven X-ray Source for Nanoscale Metrology and Femtosecond Dynamics

    SciTech Connect

    Siders, C W; Crane, J K; Semenov, V; Betts, S; Kozioziemski, B; Wharton, K; Wilks, S; Barbee, T; Stuart, B; Kim, D E; An, J; Barty, C

    2007-02-26

    This project developed and demonstrated a new, bright, ultrafast x-ray source based upon laser-driven K-alpha generation, which can produce an x-ray flux 10 to 100 times greater than current microfocus x-ray tubes. The short-pulse (sub-picosecond) duration of this x-ray source also makes it ideal for observing time-resolved dynamics of atomic motion in solids and thin films.

  8. Dependence of Initial Plasma Size on Laser-driven In-Tube Accelerator (LITA) Performance

    SciTech Connect

    Kim, Sukyum; Jeung, In-Seuck; Ohtani, Toshiro; Sasoh, Akihiro; Choi, Jeong-Yeol

    2004-03-30

    At Tohoku University, experiments of Laser-driven In-Tube Accelerator (LITA) have been carried out. In order to observe the initial state of plasma and blast wave, the visualization experiment was carried out using the shadowgraph method. In this paper, dependency of initial plasma size on LITA performance is investigated numerically. The plasma size is estimated using shadowgraph images and the numerical results are compared with the experimental data of pressure measurement and results of previous modeling.

  9. Dependence of Initial Plasma Size on Laser-driven In-Tube Accelerator (LITA) Performance

    NASA Astrophysics Data System (ADS)

    Kim, Sukyum; Ohtani, Toshiro; Sasoh, Akihiro; Jeung, In-Seuck; Choi, Jeong-Yeol

    2004-03-01

    At Tohoku University, experiments of Laser-driven In-Tube Accelerator (LITA) have been carried out. In order to observe the initial state of plasma and blast wave, the visualization experiment was carried out using the shadowgraph method. In this paper, dependency of initial plasma size on LITA performance is investigated numerically. The plasma size is estimated using shadowgraph images and the numerical results are compared with the experimental data of pressure measurement and results of previous modeling.

  10. Selective photo-activation analysis with laser-driven x-rays

    NASA Astrophysics Data System (ADS)

    Banerjee, Sudeep; Golovin, Grigory; Powers, Nathan; Liu, Cheng; Chen, Shouyuan; Petersen, Chad; Zhang, Jun; Ghebregziabher, Isaac; Zhao, Baozhen; Brown, Kevin; Mills, Jared; Umstadter, Donald; Haden, Dan; Silano, Jack; Karwowski, Hugon

    2013-04-01

    We discuss a technique for the identification of nuclear isotopes by selective photo-activation analysis. A narrow divergence beam of high-energy photons is produced when a laser driven electron beam Compton backscatters off a counter-propagating high-intensity laser pulse. The x-rays from this compact laser-driven synchrotron light source are MeV energy, narrow-bandwidth, tunable, polarized, and bright (10^8 photons s-1). Such characteristics make these x-rays well-suited for nuclear interrogation by means of triggering (γ,f) and (γ,xn) reactions. The narrow bandwidth of the x-ray light can be exploited to selectively activate nuclei with isotopic sensitivity, without causing unwanted background from collateral activation. Additionally, the polarized nature of the x-rays can be used to study anisotropy of neutron emission, for precise identification of isotopes. Activation by laser-driven synchrotron x-rays will be compared with activation by bremsstrahlung.

  11. An efficient, selective collisional ejection mechanism for inner-shell population inversion in laser-driven plasmas

    NASA Astrophysics Data System (ADS)

    Schroeder, W. Andreas; Nelson, T. R.; Borisov, A. B.; Longworth, J. W.; Boyer, K.; Rhodes, C. K.

    2001-02-01

    A theoretical analysis of laser-driven collisional ejection of inner-shell electrons is presented to explain the previously observed anomalous kilovolt L-shell x-ray emission spectra from atomic Xe cluster targets excited by intense sub-picosecond 248 nm ultraviolet radiation (McPherson A et al 1994 Nature 370 631-4). For incident ponderomotively-driven electrons photoionized by strong above threshold ionization, the collisional ejection mechanism is shown to be highly l-state and significantly n-state (i.e. radially) selective for time periods shorter than the collisional dephasing time of the photoionized electronic wavefunction. The resulting preference for the collisional ejection of 2p electrons by an ionized 4p state produces the measured anomalous Xe(L) emission which contains direct evidence for (i) the generation of Xe27+(2p53d10) and Xe28+(2p53d9) ions exhibiting inner-shell population inversion and (ii) a coherent correlated electron state collision responsible for the production of double 2p vacancies. For longer time periods, the selectivity of this coherent impact ionization mechanism is rapidly reduced by the combined effects of intrinsic quantum mechanical spreading and dephasing - in agreement with the experimentally observed and extremely strong ~λ-6 pump-laser wavelength dependence of the efficiency of inner-shell (2p) vacancy production in Xe clusters excited in underdense plasmas (Kondo K et al 1997 J. Phys. B: At. Mol. Opt. Phys. 30 2707-16).

  12. Ultrafast photoinduced enhancement of nonlinear optical response in 15-atom gold clusters on indium tin oxide conducting film.

    PubMed

    Kumar, Sunil; Shibu, E S; Pradeep, T; Sood, A K

    2013-04-01

    We show that the third order optical nonlinearity of 15-atom gold clusters is significantly enhanced when in contact with indium tin oxide (ITO) conducting film. Open and close aperture z-scan experiments together with non-degenerate pump-probe differential transmission experiments were done using 80 fs laser pulses centered at 395 nm and 790 nm on gold clusters encased inside cyclodextrin cavities. We show that two photon absorption coefficient is enhanced by an order of magnitude as compared to that when the clusters are on pristine glass plate. The enhancement for the nonlinear optical refraction coefficient is ~3 times. The photo-induced excited state absorption using pump-probe experiments at pump wavelength of 395 nm and probe at 790 nm also show an enhancement by an order of magnitude. These results attributed to the excited state energy transfer in the coupled gold cluster-ITO system are different from the enhancement seen so far in charge donor-acceptor complexes and nanoparticle-conjugate polymer composites. PMID:23571938

  13. Assessment of secondary radiation and radiation protection in laser-driven proton therapy.

    PubMed

    Faby, Sebastian; Wilkens, Jan J

    2015-06-01

    This work is a feasibility study of a radiation treatment unit with laser-driven protons based on a state-of-the-art energy selection system employing four dipole magnets in a compact shielded beamline. The secondary radiation emitted from the beamline and its energy selection system and the resulting effective dose to the patient are assessed. Further, it is evaluated whether or not such a compact system could be operated in a conventional treatment vault for clinical linear accelerators under the constraint of not exceeding the effective dose limit of 1 mSv per year to the general public outside the treatment room. The Monte Carlo code Geant4 is employed to simulate the secondary radiation generated while irradiating a hypothetical tumor. The secondary radiation inevitably generated inside the patient is taken into account as well, serving as a lower limit. The results show that the secondary radiation emanating from the shielded compact therapy system would pose a serious secondary dose contamination to the patient. This is due to the broad energy spectrum and in particular the angular distribution of the laser-driven protons, which make the investigated beamline together with the employed energy selection system quite inefficient. The secondary radiation also cannot be sufficiently absorbed in a conventional linear accelerator treatment vault to enable a clinical operation. A promising result, however, is the fact that the secondary radiation generated in the patient alone could be very well shielded by a regular treatment vault, allowing the application of more than 100 fractions of 2 Gy per day with protons. It is thus theoretically possible to treat patients with protons in such treatment vaults. Nevertheless, the results show that there is a clear need for alternative more efficient energy selection solutions for laser-driven protons. PMID:25267383

  14. Fountain effect of laser-driven relativistic electrons inside a solid dielectric

    SciTech Connect

    Sarkisov, G. S.; Jobe, D.; Spielman, R.; Leblanc, P.; Ivanov, V. V.; Sentoku, Y.; Yates, K.; Wiewior, P.; Bychenkov, V. Yu.

    2011-09-26

    Ultrafast interferometry with sub-ps resolution has been applied for the direct measurement of an electron density induced by a laser-driven relativistic electron beam inside a solid dielectric. The topology of the interference phase shift shows the signature of the ''fountain effect,'' a narrow electron beam that fans out from the propagation axis and heads back to the target surface. Two-dimensional particle-in-cell (PIC) computer simulations demonstrate radial spreading of fast electrons by self-consistent electrostatic fields. The very low ionization, {approx}0.1%, observed after the heating pulse suggests a fast recombination at the sub-ps time scale.

  15. Program to research laser-driven thermionic electron sources for free electron lasers

    NASA Astrophysics Data System (ADS)

    1988-01-01

    This is the Final Report on the research and development of high brightness pulse laser driven thermionic electron sources. Enhanced coupling of electron beam energies to radiative fields in accelerator-driven free-electron lasers requires injector cathodes of higher brightness than is possible with conventional dispenser cathodes or plasma-forming field emitters. Cesiated refractory surfaces and dispenser cathodes which are pulse laser heated may offer such an increase in brightness, by the emission of monoenergetic beams of electrons at high current densities. The studies were designed to investigate the emission characteristics of both of these types of thermionic cathodes.

  16. Characterization of laser-driven shock waves in solids using a fiber optic pressure probe

    SciTech Connect

    Cranch, Geoffrey A.; Lunsford, Robert; Grun, Jacob; Weaver, James; Compton, Steve; May, Mark; Kostinski, Natalie

    2013-11-08

    Measurement of laser-driven shock wave pressure in solid blocks of polymethyl methacrylate is demonstrated using fiber optic pressure probes. Three probes based on a fiber Fabry–Perot, fiber Bragg grating, and interferometric fiber tip sensor are tested and compared. Shock waves are generated using a high-power laser focused onto a thin foil target placed in close proximity to the test blocks. The fiber Fabry–Perot sensor appears capable of resolving the shock front with a rise time of 91 ns. As a result, the peak pressure is estimated, using a separate shadowgraphy measurement, to be 3.4 GPa.

  17. Modeling laser-driven electron acceleration using WARP with Fourier decomposition

    NASA Astrophysics Data System (ADS)

    Lee, P.; Audet, T. L.; Lehe, R.; Vay, J.-L.; Maynard, G.; Cros, B.

    2016-09-01

    WARP is used with the recent implementation of the Fourier decomposition algorithm to model laser-driven electron acceleration in plasmas. Simulations were carried out to analyze the experimental results obtained on ionization-induced injection in a gas cell. The simulated results are in good agreement with the experimental ones, confirming the ability of the code to take into account the physics of electron injection and reduce calculation time. We present a detailed analysis of the laser propagation, the plasma wave generation and the electron beam dynamics.

  18. Ultrafast Synchrotron-Enhanced Thermalization of Laser-Driven Colliding Pair Plasmas

    NASA Astrophysics Data System (ADS)

    Lobet, M.; Ruyer, C.; Debayle, A.; d'Humières, E.; Grech, M.; Lemoine, M.; Gremillet, L.

    2015-11-01

    We report on the first self-consistent numerical study of the feasibility of laser-driven relativistic pair shocks of prime interest for high-energy astrophysics. Using a QED-particle-in-cell code, we simulate the collective interaction between two counterstreaming electron-positron jets driven from solid foils by short-pulse (˜60 fs ), high-energy (˜100 kJ ) lasers. We show that the dissipation caused by self-induced, ultrastrong (>1 06 T ) electromagnetic fluctuations is amplified by intense synchrotron emission, which enhances the magnetic confinement and compression of the colliding jets.

  19. Three-dimensional Dielectric Photonic Crystal Structures for Laser-driven Acceleration

    SciTech Connect

    Cowan, Benjamin M.; /Tech-X, Boulder /SLAC

    2007-12-14

    We present the design and simulation of a three-dimensional photonic crystal waveguide for linear laser-driven acceleration in vacuum. The structure confines a synchronous speed-of-light accelerating mode in both transverse dimensions. We report the properties of this mode, including sustainable gradient and optical-to-beam efficiency. We present a novel method for confining a particle beam using optical fields as focusing elements. This technique, combined with careful structure design, is shown to have a large dynamic aperture and minimal emittance growth, even over millions of optical wavelengths.

  20. Characterization of Heat-Wave Propagation through Laser-Driven Ti-Doped Underdense Plasma

    SciTech Connect

    Tanabe, M; Nishimura, H; Ohnishi, N; Fournier, K B; Fujioka, S; Iwamae, A; Hansen, S B; Nagai, K; Girard, F; Primout, M; Villette, B; Brebion, D; Mima, K

    2009-02-23

    The propagation of a laser-driven heat-wave into a Ti-doped aerogel target was investigated. The temporal evolution of the electron temperature was derived by means of Ti K-shell x-ray spectroscopy, and compared with two-dimensional radiation hydrodynamic simulations. Reasonable agreement was obtained in the early stage of the heat-wave propagation. In the later phase, laser absorption, the propagation of the heat wave, and hydrodynamic motion interact in a complex manner, and the plasma is mostly re-heated by collision and stagnation at the target central axis.

  1. Energy Efficiency of an Intracavity Coupled, Laser-Driven Linear Accelerator Pumped by an External Laser

    SciTech Connect

    Neil Na, Y.C.; Siemann, R.H.; Byer, R.L.; /Stanford U., Phys. Dept.

    2005-06-24

    We calculate the optimum energy efficiency of a laser-driven linear accelerator by adopting a simple linear model. In the case of single bunch operation, the energy efficiency can be enhanced by incorporating the accelerator into a cavity that is pumped by an external laser. In the case of multiple bunch operation, the intracavity configuration is less advantageous because the strong wakefield generated by the electron beam is also recycled. Finally, the calculation indicates that the luminosity of a linear collider based on such a structure is comparably small if high efficiency is desired.

  2. Temporal Structure of Attosecond Pulses from Laser-Driven Coherent Synchrotron Emission

    NASA Astrophysics Data System (ADS)

    Cousens, S.; Reville, B.; Dromey, B.; Zepf, M.

    2016-02-01

    The microscopic dynamics of laser-driven coherent synchrotron emission transmitted through thin foils are investigated using particle-in-cell simulations. For normal incidence interactions, we identify the formation of two distinct electron nanobunches from which emission takes place each half-cycle of the driving laser pulse. These emissions are separated temporally by 130 as and are dominant in different frequency ranges, which is a direct consequence of the distinct characteristics of each electron nanobunch. This may be exploited through spectral filtering to isolate these emissions, generating electromagnetic pulses of duration ˜70 as .

  3. Temporal Structure of Attosecond Pulses from Laser-Driven Coherent Synchrotron Emission.

    PubMed

    Cousens, S; Reville, B; Dromey, B; Zepf, M

    2016-02-26

    The microscopic dynamics of laser-driven coherent synchrotron emission transmitted through thin foils are investigated using particle-in-cell simulations. For normal incidence interactions, we identify the formation of two distinct electron nanobunches from which emission takes place each half-cycle of the driving laser pulse. These emissions are separated temporally by 130 as and are dominant in different frequency ranges, which is a direct consequence of the distinct characteristics of each electron nanobunch. This may be exploited through spectral filtering to isolate these emissions, generating electromagnetic pulses of duration ∼70  as. PMID:26967416

  4. Single shot dynamic ellipsometry mesaurements of laser-driven shock waves

    SciTech Connect

    Bolme, C. A.

    2007-12-12

    A technique has been developed to measure the time-resolved position of a laser-driven shock wave and the subsequent material flow. Ultrafast dynamic ellipsometry, using a chirped femtosecond laser pulse, probes picosecond material dynamics in a single shot by capitalizing on the refractive index changes in the shocked material. For transparent materials, the shock velocity, the particle velocity, and the shocked material's refractive index are extracted. Hugoniot data for poly(chlorotrifluoroethylene-co-vinylidene fluoride) (Kel-F 800) was obtained using ultrafast dynamic ellipsometry, and the data agrees well with previous data on macroscopic samples obtained in plate impact gas gun experiments.

  5. Modeling of reflection-type laser-driven white lighting considering phosphor particles and surface topography.

    PubMed

    Lee, Dong-Ho; Joo, Jae-Young; Lee, Sun-Kyu

    2015-07-27

    This paper presents a model of blue laser diode (LD)-based white lighting coupled with a yellow YAG phosphor, for use in the proper design and fabrication of phosphor in automotive headlamps. First, the sample consisted of an LD, collecting lens, and phosphor was prepared that matches the model. The light distribution of the LD and the phosphor were modeled to investigate an effect of the surface topography and phosphor particle properties on the laser-driven white lighting systems by using the commercially available optical design software. Based on the proposed model, the integral spectrum distribution and the color coordinates were discussed. PMID:26367551

  6. Numerical Simulation of Laser-driven In-Tube Accelerator on Supersonic Condition

    SciTech Connect

    Kim, Sukyum; Jeung, In-Seuck; Choi, Jeong-Yeol

    2004-03-30

    Recently, several laser propulsion vehicles have been launched successfully. But these vehicles remained in a very low subsonic flight. Laser-driven In-Tube Accelerator (LITA) is developed as unique laser propulsion system at Tohoku University. In this paper, flow characteristics and momentum coupling coefficients are studied numerically in the supersonic condition with the same configuration of LITA. Because of the aerodynamic drag, the coupling coefficient could not get correctly especially at the low energy input. In this study, the coupling coefficient was calculated using the concept of the effective impulse.

  7. Numerical Simulation of Laser-driven In-Tube Accelerator on Supersonic Condition

    NASA Astrophysics Data System (ADS)

    Kim, Sukyum; Jeung, In-Seuck; Choi, Jeong-Yeol

    2004-03-01

    Recently, several laser propulsion vehicles have been launched successfully. But these vehicles remained in a very low subsonic flight. Laser-driven In-Tube Accelerator (LITA) is developed as unique laser propulsion system at Tohoku University. In this paper, flow characteristics and momentum coupling coefficients are studied numerically in the supersonic condition with the same configuration of LITA. Because of the aerodynamic drag, the coupling coefficient could not get correctly especially at the low energy input. In this study, the coupling coefficient was calculated using the concept of the effective impulse.

  8. Impulse-scaling in a laser-driven in-tube accelerator

    NASA Astrophysics Data System (ADS)

    Sasoh, A.; Urabe, N.; Kim, S. S. M.; Jeung, I.-S.

    The laser-driven in-tube accelerator (LITA) is a unique device for laser propulsion. It is characterized by the acceleration of a projectile in a tube. The thrust performance can be improved by exploiting a confinement effect. In the experiment, a 3.0-g projectile is vertically launched, and the momentum coupling coefficient is measured for various monoatomic gases. The measured coupling coefficient is almost proportional to the reciprocal of the speed of sound. The same impulse generation characteristics are obtained in simplified situations that are analyzed based on conservation relations.

  9. Vertical Launch Performance of Laser-driven In-Tube Accelerator

    NASA Astrophysics Data System (ADS)

    Urabe, Naohide; Kim, Sukyum; Sasoh, Akihiro; Jeung, In-Seuck

    2003-05-01

    We studied the vertical launch performance of the Laser-driven In-Tube Accelerator (LITA). This device is primarily characterized by accelerating a projectile in a tube. Owing to the confinement effect, the thrust performance is enhanced. The driver gas can be specified and its pressure be turned so that the impulse performance is optimized. In the experiments, a 3.0-gram projectile was vertically launched. The effects of the projectile exit condition, the laser beam incident direction and the driver gas species were experimentally studied.

  10. Ultrafast Synchrotron-Enhanced Thermalization of Laser-Driven Colliding Pair Plasmas.

    PubMed

    Lobet, M; Ruyer, C; Debayle, A; d'Humières, E; Grech, M; Lemoine, M; Gremillet, L

    2015-11-20

    We report on the first self-consistent numerical study of the feasibility of laser-driven relativistic pair shocks of prime interest for high-energy astrophysics. Using a QED-particle-in-cell code, we simulate the collective interaction between two counterstreaming electron-positron jets driven from solid foils by short-pulse (~60 fs), high-energy (~100 kJ) lasers. We show that the dissipation caused by self-induced, ultrastrong (>10^{6} T) electromagnetic fluctuations is amplified by intense synchrotron emission, which enhances the magnetic confinement and compression of the colliding jets. PMID:26636856

  11. Using laser-driven flyer plates to study the shock initiation of nanoenergetic materials

    NASA Astrophysics Data System (ADS)

    Shaw, W. L.; Williams, R. A.; Dreizin, E. L.; Dlott, D. D.

    2014-05-01

    A tabletop system has been developed to launch aluminium laser-driven flyer plates at speeds of up to 4 km/s. The flyers were used to initiate nanoenergetic reactive materials including aluminium/iron oxide and aluminium/molybdenum oxide thermites produced by arrested reactive milling. The flyer flight and impact was characterized by photon Doppler velocimetry and the initiation process by time-resolved emission spectroscopy. Impact initiation thresholds were determined for 50 μm thick flyer plates producing 10 ns shocks. The intensities, delays and durations of the emission bursts, and the effects of nanostructure and microstructure on them were used to investigate fundamental mechanisms of impact initiation.

  12. Nonlinear mapping technique for data visualization and clustering assessment of LIBS data: application to ChemCam data.

    PubMed

    Lasue, J; Wiens, R C; Stepinski, T F; Forni, O; Clegg, S M; Maurice, S

    2011-07-01

    ChemCam is a remote laser-induced breakdown spectroscopy (LIBS) instrument that will arrive on Mars in 2012, on-board the Mars Science Laboratory Rover. The LIBS technique is crucial to accurately identify samples and quantify elemental abundances at various distances from the rover. In this study, we compare different linear and nonlinear multivariate techniques to visualize and discriminate clusters in two dimensions (2D) from the data obtained with ChemCam. We have used principal components analysis (PCA) and independent components analysis (ICA) for the linear tools and compared them with the nonlinear Sammon's map projection technique. We demonstrate that the Sammon's map gives the best 2D representation of the data set, with optimization values from 2.8% to 4.3% (0% is a perfect representation), together with an entropy value of 0.81 for the purity of the clustering analysis. The linear 2D projections result in three (ICA) and five times (PCA) more stress, and their clustering purity is more than twice higher with entropy values about 1.8. We show that the Sammon's map algorithm is faster and gives a slightly better representation of the data set if the initial conditions are taken from the ICA projection rather than the PCA projection. We conclude that the nonlinear Sammon's map projection is the best technique for combining data visualization and clustering assessment of the ChemCam LIBS data in 2D. PCA and ICA projections on more dimensions would improve on these numbers at the cost of the intuitive interpretation of the 2D projection by a human operator. PMID:21331488

  13. Strong non-linear effects in the chiroptical properties of the ligand-exchanged Au38 and Au40 clusters

    NASA Astrophysics Data System (ADS)

    Knoppe, Stefan; Dass, Amala; Bürgi, Thomas

    2012-06-01

    Ligand exchange reactions on size-selected Au38(2-PET)24 and Au40(2-PET)24 clusters (2-PET: 2-phenylethylthiol) with mono- and bi-dentate chiral thiols were performed. The reactions were monitored with MALDI mass spectrometry and the arising chiroptical properties were compared to the number of incorporated chiral ligands. Only a small fraction of chiral ligands is needed to induce significant optical activity to the clusters. The use of bidentate 1,1'-binaphthyl-2,2'-dithiol (BINAS) leads to slow exchange, but the optical activity measured is strong. Moreover, a non-linear behaviour between optical activity and the number of chiral ligands is found in the BINAS case for both Au38 and Au40, which may indicate different exchange rates of enantiopure BINAS with the enantiomers of inherently chiral (but racemic) clusters. This is ascribed to effects arising from the bidentate nature of BINAS. In contrast, the use of monodentate camphor-10-thiol (CamSH) leads to comparably fast exchange on both clusters. The arising optical activity is weak. This is the first study where chiroptical effects are directly correlated with the composition of the ligand shell.Ligand exchange reactions on size-selected Au38(2-PET)24 and Au40(2-PET)24 clusters (2-PET: 2-phenylethylthiol) with mono- and bi-dentate chiral thiols were performed. The reactions were monitored with MALDI mass spectrometry and the arising chiroptical properties were compared to the number of incorporated chiral ligands. Only a small fraction of chiral ligands is needed to induce significant optical activity to the clusters. The use of bidentate 1,1'-binaphthyl-2,2'-dithiol (BINAS) leads to slow exchange, but the optical activity measured is strong. Moreover, a non-linear behaviour between optical activity and the number of chiral ligands is found in the BINAS case for both Au38 and Au40, which may indicate different exchange rates of enantiopure BINAS with the enantiomers of inherently chiral (but racemic) clusters

  14. Terahertz generation by nonlinear mixing of laser pulses in a clustered gas

    SciTech Connect

    Kumar, Manoj; Tripathi, V. K.

    2011-05-15

    A scheme of terahertz (THz) generation by two collinear laser pulses of finite spot size in a clustered gas is investigated theoretically. The lasers quickly ionize the atoms of the clusters, converting them into plasma balls, and exert a ponderomotive force on the cluster electrons, producing a beat frequency longitudinal current of limited transverse extent. The current acts as an antenna to produce beat frequency terahertz radiation. As the cluster expands under the hydrodynamic pressure, plasma frequency of cluster electrons {omega}{sub pe} decreases and approaches {radical}(3) times the frequency of laser, resonant heating and expansion of clusters occurs. On further expansion of clusters as {omega}{sub pe} approaches {radical}(3) times the terahertz frequency, resonant enhancement in THz radiated power occurs.

  15. The Laser-driven Flyer System for Space Debris Hypervelocity Impact Simulations

    NASA Astrophysics Data System (ADS)

    Gong, Zizheng; Dai, Fu; Yang, Jiyun; Hou, Mingqiang; Zheng, Jiandong; Tong, Jingyu; Pang, Hewei

    2009-06-01

    The Laser-driven flyer (LDF) technique is showing promiseful in simulating micro meteoroids and orbital debris (M/OD) hypervelocity impacting effects. LDF system with a single pulses from a Q-switched Nd: glass laser, of 15 ns duration and up to 20J energy, launched the aluminum films of 5 μm thickness up to 8.3km/s velocity was developed in Beijing Institute of Spacecrafts Environment Engineering(BISEE), CAST. The quantitative relationships between the flyer velocity and the laser energy, the width of laser pulse, the diameter of laser focal spot, and the flyer thickness were analyzed, according to Lawrence-Gurney model, and compared with the experimental results. Some experimental aspects in our efforts on the space debris Hypervelocity impacts on the outer surfaces functional material, such as the thermal control material, window glass, and OSR etc., are reviewed. Though still developing, the Laser-driven flyer technique has been demonstrated promise in simulating micro M/OD hypervelocity impacting effects.

  16. Guided post-acceleration of laser-driven ions by a miniature modular structure.

    PubMed

    Kar, Satyabrata; Ahmed, Hamad; Prasad, Rajendra; Cerchez, Mirela; Brauckmann, Stephanie; Aurand, Bastian; Cantono, Giada; Hadjisolomou, Prokopis; Lewis, Ciaran L S; Macchi, Andrea; Nersisyan, Gagik; Robinson, Alexander P L; Schroer, Anna M; Swantusch, Marco; Zepf, Matt; Willi, Oswald; Borghesi, Marco

    2016-01-01

    All-optical approaches to particle acceleration are currently attracting a significant research effort internationally. Although characterized by exceptional transverse and longitudinal emittance, laser-driven ion beams currently have limitations in terms of peak ion energy, bandwidth of the energy spectrum and beam divergence. Here we introduce the concept of a versatile, miniature linear accelerating module, which, by employing laser-excited electromagnetic pulses directed along a helical path surrounding the laser-accelerated ion beams, addresses these shortcomings simultaneously. In a proof-of-principle experiment on a university-scale system, we demonstrate post-acceleration of laser-driven protons from a flat foil at a rate of 0.5 GeV m(-1), already beyond what can be sustained by conventional accelerator technologies, with dynamic beam collimation and energy selection. These results open up new opportunities for the development of extremely compact and cost-effective ion accelerators for both established and innovative applications. PMID:27089200

  17. The ELIMED transport and dosimetry beamline for laser-driven ion beams

    NASA Astrophysics Data System (ADS)

    Romano, F.; Schillaci, F.; Cirrone, G. A. P.; Cuttone, G.; Scuderi, V.; Allegra, L.; Amato, A.; Amico, A.; Candiano, G.; De Luca, G.; Gallo, G.; Giordanengo, S.; Guarachi, L. Fanola; Korn, G.; Larosa, G.; Leanza, R.; Manna, R.; Marchese, V.; Marchetto, F.; Margarone, D.; Milluzzo, G.; Petringa, G.; Pipek, J.; Pulvirenti, S.; Rizzo, D.; Sacchi, R.; Salamone, S.; Sedita, M.; Vignati, A.

    2016-09-01

    A growing interest of the scientific community towards multidisciplinary applications of laser-driven beams has led to the development of several projects aiming to demonstrate the possible use of these beams for therapeutic purposes. Nevertheless, laser-accelerated particles differ from the conventional beams typically used for multiscipilinary and medical applications, due to the wide energy spread, the angular divergence and the extremely intense pulses. The peculiarities of optically accelerated beams led to develop new strategies and advanced techniques for transport, diagnostics and dosimetry of the accelerated particles. In this framework, the realization of the ELIMED (ELI-Beamlines MEDical and multidisciplinary applications) beamline, developed by INFN-LNS (Catania, Italy) and that will be installed in 2017 as a part of the ELIMAIA beamline at the ELI-Beamlines (Extreme Light Infrastructure Beamlines) facility in Prague, has the aim to investigate the feasibility of using laser-driven ion beams for multidisciplinary applications. In this contribution, an overview of the beamline along with a detailed description of the main transport elements as well as the detectors composing the final section of the beamline will be presented.

  18. Guided post-acceleration of laser-driven ions by a miniature modular structure

    PubMed Central

    Kar, Satyabrata; Ahmed, Hamad; Prasad, Rajendra; Cerchez, Mirela; Brauckmann, Stephanie; Aurand, Bastian; Cantono, Giada; Hadjisolomou, Prokopis; Lewis, Ciaran L. S.; Macchi, Andrea; Nersisyan, Gagik; Robinson, Alexander P. L.; Schroer, Anna M.; Swantusch, Marco; Zepf, Matt; Willi, Oswald; Borghesi, Marco

    2016-01-01

    All-optical approaches to particle acceleration are currently attracting a significant research effort internationally. Although characterized by exceptional transverse and longitudinal emittance, laser-driven ion beams currently have limitations in terms of peak ion energy, bandwidth of the energy spectrum and beam divergence. Here we introduce the concept of a versatile, miniature linear accelerating module, which, by employing laser-excited electromagnetic pulses directed along a helical path surrounding the laser-accelerated ion beams, addresses these shortcomings simultaneously. In a proof-of-principle experiment on a university-scale system, we demonstrate post-acceleration of laser-driven protons from a flat foil at a rate of 0.5 GeV m−1, already beyond what can be sustained by conventional accelerator technologies, with dynamic beam collimation and energy selection. These results open up new opportunities for the development of extremely compact and cost-effective ion accelerators for both established and innovative applications. PMID:27089200

  19. Shielded radiography with a laser-driven MeV-energy X-ray source

    NASA Astrophysics Data System (ADS)

    Chen, Shouyuan; Golovin, Grigory; Miller, Cameron; Haden, Daniel; Banerjee, Sudeep; Zhang, Ping; Liu, Cheng; Zhang, Jun; Zhao, Baozhen; Clarke, Shaun; Pozzi, Sara; Umstadter, Donald

    2016-01-01

    We report the results of experimental and numerical-simulation studies of shielded radiography using narrowband MeV-energy X-rays from a compact all-laser-driven inverse-Compton-scattering X-ray light source. This recently developed X-ray light source is based on a laser-wakefield accelerator with ultra-high-field gradient (GeV/cm). We demonstrate experimentally high-quality radiographic imaging (image contrast of 0.4 and signal-to-noise ratio of 2:1) of a target composed of 8-mm thick depleted uranium shielded by 80-mm thick steel, using a 6-MeV X-ray beam with a spread of 45% (FWHM) and 107 photons in a single shot. The corresponding dose of the X-ray pulse measured in front of the target is ∼100 nGy/pulse. Simulations performed using the Monte-Carlo code MCNPX accurately reproduce the experimental results. These simulations also demonstrate that the narrow bandwidth of the Compton X-ray source operating at 6 and 9 MeV leads to a reduction of deposited dose as compared to broadband bremsstrahlung sources with the same end-point energy. The X-ray beam's inherently low-divergence angle (∼mrad) is advantageous and effective for interrogation at standoff distance. These results demonstrate significant benefits of all-laser driven Compton X-rays for shielded radiography.

  20. Application of a transmission crystal x-ray spectrometer to moderate-intensity laser driven sources

    SciTech Connect

    Mao, J. Y.; Chen, L. M.; Zhang, L.; Sun, Y. Q.; Lin, X. X.; Hudson, L. T.; Seely, J. F.; Zhang, J.

    2012-04-15

    In the pursuit of novel, laser-produced x-ray sources for medical imaging applications, appropriate instrumental diagnostics need to be developed concurrently. A type of transmission crystal spectroscopy has previously been demonstrated as a survey tool for sources produced by high-power and high-energy lasers. The present work demonstrates the extension of this method into the study of medium-intensity laser driven hard x-ray sources with a design that preserves resolving power while maintaining high sensitivity. Specifically, spectroscopic measurements of characteristic K{alpha} and K{beta} emissions were studied from Mo targets irradiated by a 100 fs, 200 mJ, Ti: sapphire laser with intensity of 10{sup 17} W/cm{sup 2} to 10{sup 18} W/cm{sup 2} per shot. Using a transmission curved crystal spectrometer and off-Rowland circle imaging, resolving powers (E/{Delta}E) of around 300 for Mo K{alpha}{sub 2} at 17.37 keV were obtained with an end-to-end spectrometer efficiency of (1.13 {+-} 0.10) x 10{sup -5}. This sensitivity is sufficient for registering x-ray lines with high signal to background from targets following irradiation by a single laser pulse, demonstrating the utility of this method in the study of the development of medium-intensity laser driven x-ray sources.

  1. Dynamic control of laser driven proton beams by exploiting self-generated, ultrashort electromagnetic pulses

    NASA Astrophysics Data System (ADS)

    Kar, S.; Ahmed, H.; Nersisyan, G.; Brauckmann, S.; Hanton, F.; Giesecke, A. L.; Naughton, K.; Willi, O.; Lewis, C. L. S.; Borghesi, M.

    2016-05-01

    As part of the ultrafast charge dynamics initiated by high intensity laser irradiations of solid targets, high amplitude EM pulses propagate away from the interaction point and are transported along any stalks and wires attached to the target. The propagation of these high amplitude pulses along a thin wire connected to a laser irradiated target was diagnosed via the proton radiography technique, measuring a pulse duration of ˜20 ps and a pulse velocity close to the speed of light. The strong electric field associated with the EM pulse can be exploited for controlling dynamically the proton beams produced from a laser-driven source. Chromatic divergence control of broadband laser driven protons (upto 75% reduction in divergence of >5 MeV protons) was obtained by winding the supporting wire around the proton beam axis to create a helical coil structure. In addition to providing focussing and energy selection, the technique has the potential to post-accelerate the transiting protons by the longitudinal component of the curved electric field lines produced by the helical coil lens.

  2. Determination of critical energy criteria for hexanitrostilbene using laser-driven flyer plates

    NASA Astrophysics Data System (ADS)

    Bowden, Mike D.; Maisey, Matthew P.

    2008-08-01

    Laser-driven flyer plates comprise of one or more thin layers forming a foil coated onto a transparent substrate. Irradiation of the foil/substrate interface with a Q-switched laser pulse produces a plasma, the expansion of which forms a flyer plate, which can reach velocities in excess of 5 km/s. These plates impart shocks in excess of 50 GPa, with duration of less than a nanosecond. This shock is sufficient to initiate secondary explosives such as Hexanitrostilbene (HNS) and Pentaerythritol Tetranitrate (PETN). Thresholds of detonators based on laser-driven flyer plates are typically measured in terms of energy. By using a Photonic Doppler Velocimeter (PDV) we measure the velocity of the flyer plate at the threshold energy. This allows calculation of the shock pressure and duration imparted to the explosive. By initiating HNS with a variety of flyer thicknesses, from 3 to 5 μm, we are able to evaluate Pnτ in this extreme shock regime. The calculated value of n is compared to published values and discussed for similar systems. We are also able to use the James Criterion to analyze the initiation, with values of Ec and Σc being determined from experimental data, providing a predictive capability to model other configurations such as different flyer thicknesses and materials.

  3. Laser driven single shock compression of fluid deuterium from 45 to 220 GPa

    SciTech Connect

    Hicks, D; Boehly, T; Celliers, P; Eggert, J; Moon, S; Meyerhofer, D; Collins, G

    2008-03-23

    The compression {eta} of liquid deuterium between 45 and 220 GPa under laser-driven shock loading has been measured using impedance matching to an aluminum (Al) standard. An Al impedance match model derived from a best fit to absolute Hugoniot data has been used to quantify and minimize the systematic errors caused by uncertainties in the high-pressure Al equation of state. In deuterium below 100 GPa results show that {eta} {approx_equal} 4.2, in agreement with previous impedance match data from magnetically-driven flyer and convergent-explosive shock wave experiments; between 100 and 220 GPa {eta} reaches a maximum of {approx}5.0, less than the 6-fold compression observed on the earliest laser-shock experiments but greater than expected from simple extrapolations of lower pressure data. Previous laser-driven double-shock results are found to be in good agreement with these single-shock measurements over the entire range under study. Both sets of laser-shock data indicate that deuterium undergoes an abrupt increase in compression at around 110 GPa.

  4. A technology platform for translational research on laser driven particle accelerators for radiotherapy

    NASA Astrophysics Data System (ADS)

    Enghardt, W.; Bussmann, M.; Cowan, T.; Fiedler, F.; Kaluza, M.; Pawelke, J.; Schramm, U.; Sauerbrey, R.; Tünnermann, A.; Baumann, M.

    2011-05-01

    It is widely accepted that proton or light ion beams may have a high potential for improving cancer cure by means of radiation therapy. However, at present the large dimensions of electromagnetic accelerators prevent particle therapy from being clinically introduced on a broad scale. Therefore, several technological approaches among them laser driven particle acceleration are under investigation. Parallel to the development of suitable high intensity lasers, research is necessary to transfer laser accelerated particle beams to radiotherapy, since the relevant parameters of laser driven particle beams dramatically differ from those of beams delivered by conventional accelerators: The duty cycle is low, whereas the number of particles and thus the dose rate per pulse are high. Laser accelerated particle beams show a broad energy spectrum and substantial intensity fluctuations from pulse to pulse. These properties may influence the biological efficiency and they require completely new techniques of beam delivery and quality assurance. For this translational research a new facility is currently constructed on the campus of the university hospital Dresden. It will be connected to the department of radiooncology and host a petawatt laser system delivering an experimental proton beam and a conventional therapeutic proton cyclotron. The cyclotron beam will be delivered on the one hand to an isocentric gantry for patient treatments and on the other hand to an experimental irradiation site. This way the conventional accelerator will deliver a reference beam for all steps of developing the laser based technology towards clinical applicability.

  5. X-ray phase-contrast tomography with a compact laser-driven synchrotron source

    PubMed Central

    Eggl, Elena; Schleede, Simone; Bech, Martin; Achterhold, Klaus; Loewen, Roderick; Ruth, Ronald D.; Pfeiffer, Franz

    2015-01-01

    Between X-ray tubes and large-scale synchrotron sources, a large gap in performance exists with respect to the monochromaticity and brilliance of the X-ray beam. However, due to their size and cost, large-scale synchrotrons are not available for more routine applications in small and medium-sized academic or industrial laboratories. This gap could be closed by laser-driven compact synchrotron light sources (CLS), which use an infrared (IR) laser cavity in combination with a small electron storage ring. Hard X-rays are produced through the process of inverse Compton scattering upon the intersection of the electron bunch with the focused laser beam. The produced X-ray beam is intrinsically monochromatic and highly collimated. This makes a CLS well-suited for applications of more advanced––and more challenging––X-ray imaging approaches, such as X-ray multimodal tomography. Here we present, to our knowledge, the first results of a first successful demonstration experiment in which a monochromatic X-ray beam from a CLS was used for multimodal, i.e., phase-, dark-field, and attenuation-contrast, X-ray tomography. We show results from a fluid phantom with different liquids and a biomedical application example in the form of a multimodal CT scan of a small animal (mouse, ex vivo). The results highlight particularly that quantitative multimodal CT has become feasible with laser-driven CLS, and that the results outperform more conventional approaches. PMID:25902493

  6. Fabrication of nanostructured targets for improved laser-driven proton acceleration

    NASA Astrophysics Data System (ADS)

    Barberio, M.; Scisciò, M.; Veltri, S.; Antici, P.

    2016-07-01

    In this work, we present a novel realization of nanostructured targets suitable for improving laser-driven proton acceleration experiments, in particular with regard to the Target-Normal-Sheath Acceleration (TNSA) acceleration mechanism. The nanostructured targets, produced as films, are realized by a simpler and cheaper method than using conventional lithographic techniques. The growth process includes a two step approach for the production of the gold nanoparticle layers: 1) Laser Ablation in Solution and 2) spray-dry technique using a colloidal solution on target surfaces (Aluminum, Mylar and Multi Walled Carbon Nanotube). The obtained nanostructured films appear, at morphological and chemical analysis, uniformly nanostructured and the nanostructure distributed on the target surfaces without presence of oxides or external contaminants. The obtained targets show a broad optical absorption in all the visible region and a surface roughness that is two times greater than non-nanostructured targets, enabling a greater laser energy absorption during the laser-matter interaction experiments producing the laser-driven proton acceleration.

  7. Towards optical polarization control of laser-driven proton acceleration in foils undergoing relativistic transparency.

    PubMed

    Gonzalez-Izquierdo, Bruno; King, Martin; Gray, Ross J; Wilson, Robbie; Dance, Rachel J; Powell, Haydn; Maclellan, David A; McCreadie, John; Butler, Nicholas M H; Hawkes, Steve; Green, James S; Murphy, Chris D; Stockhausen, Luca C; Carroll, David C; Booth, Nicola; Scott, Graeme G; Borghesi, Marco; Neely, David; McKenna, Paul

    2016-01-01

    Control of the collective response of plasma particles to intense laser light is intrinsic to relativistic optics, the development of compact laser-driven particle and radiation sources, as well as investigations of some laboratory astrophysics phenomena. We recently demonstrated that a relativistic plasma aperture produced in an ultra-thin foil at the focus of intense laser radiation can induce diffraction, enabling polarization-based control of the collective motion of plasma electrons. Here we show that under these conditions the electron dynamics are mapped into the beam of protons accelerated via strong charge-separation-induced electrostatic fields. It is demonstrated experimentally and numerically via 3D particle-in-cell simulations that the degree of ellipticity of the laser polarization strongly influences the spatial-intensity distribution of the beam of multi-MeV protons. The influence on both sheath-accelerated and radiation pressure-accelerated protons is investigated. This approach opens up a potential new route to control laser-driven ion sources. PMID:27624920

  8. X-ray phase-contrast tomography with a compact laser-driven synchrotron source.

    PubMed

    Eggl, Elena; Schleede, Simone; Bech, Martin; Achterhold, Klaus; Loewen, Roderick; Ruth, Ronald D; Pfeiffer, Franz

    2015-05-01

    Between X-ray tubes and large-scale synchrotron sources, a large gap in performance exists with respect to the monochromaticity and brilliance of the X-ray beam. However, due to their size and cost, large-scale synchrotrons are not available for more routine applications in small and medium-sized academic or industrial laboratories. This gap could be closed by laser-driven compact synchrotron light sources (CLS), which use an infrared (IR) laser cavity in combination with a small electron storage ring. Hard X-rays are produced through the process of inverse Compton scattering upon the intersection of the electron bunch with the focused laser beam. The produced X-ray beam is intrinsically monochromatic and highly collimated. This makes a CLS well-suited for applications of more advanced--and more challenging--X-ray imaging approaches, such as X-ray multimodal tomography. Here we present, to our knowledge, the first results of a first successful demonstration experiment in which a monochromatic X-ray beam from a CLS was used for multimodal, i.e., phase-, dark-field, and attenuation-contrast, X-ray tomography. We show results from a fluid phantom with different liquids and a biomedical application example in the form of a multimodal CT scan of a small animal (mouse, ex vivo). The results highlight particularly that quantitative multimodal CT has become feasible with laser-driven CLS, and that the results outperform more conventional approaches. PMID:25902493

  9. Study of transport of laser-driven relativistic electrons in solid materials

    NASA Astrophysics Data System (ADS)

    Leblanc, Philippe

    With the ultra intense lasers available today, it is possible to generate very hot electron beams in solid density materials. These intense laser-matter interactions result in many applications which include the generation of ultrashort secondary sources of particles and radiation such as ions, neutrons, positrons, x-rays, or even laser-driven hadron therapy. For these applications to become reality, a comprehensive understanding of laser-driven energy transport including hot electron generation through the various mechanisms of ionization, and their subsequent transport in solid density media is required. This study will focus on the characterization of electron transport effects in solid density targets using the state-of- the-art particle-in-cell code PICLS. A number of simulation results will be presented on the topics of ionization propagation in insulator glass targets, non-equilibrium ionization modeling featuring electron impact ionization, and electron beam guiding by the self-generated resistive magnetic field. An empirically derived scaling relation for the resistive magnetic in terms of the laser parameters and material properties is presented and used to derive a guiding condition. This condition may prove useful for the design of future laser-matter interaction experiments.

  10. Radiation reaction effect on laser driven auto-resonant particle acceleration

    SciTech Connect

    Sagar, Vikram; Sengupta, Sudip; Kaw, P. K.

    2015-12-15

    The effects of radiation reaction force on laser driven auto-resonant particle acceleration scheme are studied using Landau-Lifshitz equation of motion. These studies are carried out for both linear and circularly polarized laser fields in the presence of static axial magnetic field. From the parametric study, a radiation reaction dominated region has been identified in which the particle dynamics is greatly effected by this force. In the radiation reaction dominated region, the two significant effects on particle dynamics are seen, viz., (1) saturation in energy gain by the initially resonant particle and (2) net energy gain by an initially non-resonant particle which is caused due to resonance broadening. It has been further shown that with the relaxation of resonance condition and with optimum choice of parameters, this scheme may become competitive with the other present-day laser driven particle acceleration schemes. The quantum corrections to the Landau-Lifshitz equation of motion have also been taken into account. The difference in the energy gain estimates of the particle by the quantum corrected and classical Landau-Lifshitz equation is found to be insignificant for the present day as well as upcoming laser facilities.

  11. Laser-driven ion sources for metal ion implantation for the reduction of dry friction

    SciTech Connect

    Boody, F. P.; Juha, L.; Kralikova, B.; Krasa, J.; Laska, L.; Masek, K.; Pfeifer, M.; Rohlena, K.; Skala, J.; Straka, P.; Perina, V.; Woryna, E.; Giersch, D.; Hoepfl, R.; Kelly, J. C.; Hora, H.

    1997-04-15

    The anomalously high ion currents and very high ionization levels of laser-produced plasmas give laser-driven ion sources significant advantages over conventional ion sources. In particular, laser-driven ion sources should provide higher currents of metal ions at lower cost, for implantation into solids in order to improve their material properties such as friction. The energy and charge distributions for Pb and Sn ions produced by ablation of solid targets with {approx}25 J, {approx}300 ps iodine laser pulses, resulting in up to 48-times ionized MeV ions, as well as the optimization of focus position, are presented. Implantation of these ions into Ck-45 steel, without electrostatic acceleration, produced profiles with two regions. Almost all of the ions were implanted in a near surface region a few nm deep. However, a small but significant number of ions were implanted as deep as could be measured with Rutherford backscattering (RBS), here 150 nm for Sn and 250 nm for Pb. For the implanted ion densities and profiles achieved, no change in the coefficient of friction was measured for either ion.

  12. Impulse Generation Mechanisms in a Laser-Driven In-Tube Accelerator

    NASA Astrophysics Data System (ADS)

    Choi, Jeong-Yeol; Kang, Ki-Ha; Sasoh, Akihiro; Jeung, In-Seuck; Urabe, Naohide; Kleine, Harald

    To enhance laser-propulsion thrust performance, a unique Laser-driven In-Tube Accelerator (LITA) has been developed. This paper numerically analyzes the impulse generation mechanisms in LITA. For this purpose, a LITA performance experiment was conducted in atmospheric air with a projectile installed on a ballistic pendulum to calibrate the numerical approximations. We conducted experimental flow visualization by framing shadowgraph and computational fluid dynamics solving the axi-symmetric Euler equation applied to an ideal gas. The results show that a laser-driven blast wave is generated by a spherical hot gas core where the supplied laser energy is absorbed first. The effect of confinement by the tube or shroud wall is confirmed. The impulse production is established not only from the interaction between the incident blast wave and projectile, but also from the following repetitive pressure waves. Assuming that about 30% of the input laser energy is absorbed by the working air, both the impulse and peak pressure agrees quantitatively between the experiment and numerical simulation.

  13. Uniform heating of materials into the warm dense matter regime with laser-driven quasimonoenergetic ion beams

    NASA Astrophysics Data System (ADS)

    Bang, W.; Albright, B. J.; Bradley, P. A.; Vold, E. L.; Boettger, J. C.; Fernández, J. C.

    2015-12-01

    In a recent experiment at the Trident laser facility, a laser-driven beam of quasimonoenergetic aluminum ions was used to heat solid gold and diamond foils isochorically to 5.5 and 1.7 eV, respectively. Here theoretical calculations are presented that suggest the gold and diamond were heated uniformly by these laser-driven ion beams. According to calculations and SESAME equation-of-state tables, laser-driven aluminum ion beams achievable at Trident, with a finite energy spread of ΔE /E ˜20 %, are expected to heat the targets more uniformly than a beam of 140-MeV aluminum ions with zero energy spread. The robustness of the expected heating uniformity relative to the changes in the incident ion energy spectra is evaluated, and expected plasma temperatures of various target materials achievable with the current experimental platform are presented.

  14. Uniform heating of materials into the warm dense matter regime with laser-driven quasimonoenergetic ion beams

    DOE PAGESBeta

    Bang, W.; Albright, B. J.; Bradley, P. A.; Vold, E. L.; Boettger, J. C.; Fernández, J. C.

    2015-12-01

    In a recent experiment at the Trident laser facility, a laser-driven beam of quasimonoenergetic aluminum ions was used to heat solid gold and diamond foils isochorically to 5.5 and 1.7 eV, respectively. Here theoretical calculations are presented that suggest the gold and diamond were heated uniformly by these laser-driven ion beams. According to calculations and SESAME equation-of-state tables, laser-driven aluminum ion beams achievable at Trident, with a finite energy spread of ΔE/E~20%, are expected to heat the targets more uniformly than a beam of 140-MeV aluminum ions with zero energy spread. As a result, the robustness of the expected heatingmore » uniformity relative to the changes in the incident ion energy spectra is evaluated, and expected plasma temperatures of various target materials achievable with the current experimental platform are presented.« less

  15. Uniform heating of materials into the warm dense matter regime with laser-driven quasimonoenergetic ion beams

    SciTech Connect

    Bang, W.; Albright, B. J.; Bradley, P. A.; Vold, E. L.; Boettger, J. C.; Fernández, J. C.

    2015-12-01

    In a recent experiment at the Trident laser facility, a laser-driven beam of quasimonoenergetic aluminum ions was used to heat solid gold and diamond foils isochorically to 5.5 and 1.7 eV, respectively. Here theoretical calculations are presented that suggest the gold and diamond were heated uniformly by these laser-driven ion beams. According to calculations and SESAME equation-of-state tables, laser-driven aluminum ion beams achievable at Trident, with a finite energy spread of ΔE/E~20%, are expected to heat the targets more uniformly than a beam of 140-MeV aluminum ions with zero energy spread. As a result, the robustness of the expected heating uniformity relative to the changes in the incident ion energy spectra is evaluated, and expected plasma temperatures of various target materials achievable with the current experimental platform are presented.

  16. Compact disposal of high-energy electron beams using passive or laser-driven plasma decelerating stage

    SciTech Connect

    Bonatto, A.; Schroeder, C. B.; Vay, J. -L.; Geddes, C. R.; Benedetti, C.; Esarey and, E.; Leemans, W. P.

    2014-07-13

    A plasma decelerating stage is investigated as a compact alternative for the disposal of high-energy beams (beam dumps). This could benefit the design of laser-driven plasma accelerator (LPA) applications that require transportability and or high-repetition-rate operation regimes. Passive and laser-driven (active) plasma-based beam dumps are studied analytically and with particle-in-cell (PIC) simulations in a 1D geometry. Analytical estimates for the beam energy loss are compared to and extended by the PIC simulations, showing that with the proposed schemes a beam can be efficiently decelerated in a centimeter-scale distance.

  17. Influence of electromagnetic oscillating two-stream instability on the evolution of laser-driven plasma beat-wave

    SciTech Connect

    Gupta, D. N.; Singh, K. P.; Suk, H.

    2007-01-15

    The electrostatic oscillating two-stream instability of laser-driven plasma beat-wave was studied recently by Gupta et al. [Phys. Plasmas 11, 5250 (2004)], who applied their theory to limit the amplitude level of a plasma wave in the beat-wave accelerator. As a self-generated magnetic field is observed in laser-produced plasma, hence, the electromagnetic oscillating two-stream instability may be another possible mechanism for the saturation of laser-driven plasma beat-wave. The efficiency of this scheme is higher than the former.

  18. Towards a novel laser-driven method of exotic nuclei extraction-acceleration for fundamental physics and technology

    NASA Astrophysics Data System (ADS)

    Nishiuchi, M.; Sakaki, H.; Esirkepov, T. Zh.; Nishio, K.; Pikuz, T. A.; Faenov, A. Ya.; Skobelev, I. Yu.; Orlandi, R.; Pirozhkov, A. S.; Sagisaka, A.; Ogura, K.; Kanasaki, M.; Kiriyama, H.; Fukuda, Y.; Koura, H.; Kando, M.; Yamauchi, T.; Watanabe, Y.; Bulanov, S. V.; Kondo, K.; Imai, K.; Nagamiya, S.

    2016-04-01

    A combination of a petawatt laser and nuclear physics techniques can crucially facilitate the measurement of exotic nuclei properties. With numerical simulations and laser-driven experiments we show prospects for the Laser-driven Exotic Nuclei extraction-acceleration method proposed in [M. Nishiuchi et al., Phys, Plasmas 22, 033107 (2015)]: a femtosecond petawatt laser, irradiating a target bombarded by an external ion beam, extracts from the target and accelerates to few GeV highly charged short-lived heavy exotic nuclei created in the target via nuclear reactions.

  19. Demonstartion of density dependence of x-ray flux in a laser-driven hohlraum

    SciTech Connect

    Young, P E; Rosen, M D; Hammer, J H; Hsing, W S; Glendinning, S G; Turner, R E; Kirkwood, R; Schein, J; Sorce, C; Satcher, J; Hamza, A; Reibold, R A; Hibbard, R; Landen, O; Reighard, A; McAlpin, S; Stevenson, M; Thomas, B

    2008-02-11

    Experiments have been conducted using laser-driven cylindrical hohlraums whose walls are machined from Ta{sub 2}O{sub 5} foams of 100 mg/cc and 4 g/cc densities. Measurements of the radiation temperature demonstrate that the lower density walls produce higher radiation temperatures than the high density walls. This is the first experimental demonstration of the prediction that this would occur [M. D. Rosen and J. H. Hammer, Phys. Rev. E 72, 056403 (2005)]. For high density walls, the radiation front propagates subsonically, and part of the absorbed energy is wasted by the flow kinetic energy. For the lower wall density, the front velocity is supersonic and can devote almost all of the absorbed energy to heating the wall.

  20. Efficient quasi-monoenergetic ion beams from laser-driven relativistic plasmas

    PubMed Central

    Palaniyappan, Sasi; Huang, Chengkun; Gautier, Donald C.; Hamilton, Christopher E.; Santiago, Miguel A.; Kreuzer, Christian; Sefkow, Adam B.; Shah, Rahul C.; Fernández, Juan C.

    2015-01-01

    Table-top laser–plasma ion accelerators have many exciting applications, many of which require ion beams with simultaneous narrow energy spread and high conversion efficiency. However, achieving these requirements has been elusive. Here we report the experimental demonstration of laser-driven ion beams with narrow energy spread and energies up to 18 MeV per nucleon and ∼5% conversion efficiency (that is 4 J out of 80-J laser). Using computer simulations we identify a self-organizing scheme that reduces the ion energy spread after the laser exits the plasma through persisting self-generated plasma electric (∼1012 V m−1) and magnetic (∼104 T) fields. These results contribute to the development of next generation compact accelerators suitable for many applications such as isochoric heating for ion-fast ignition and producing warm dense matter for basic science. PMID:26657147

  1. A compact broadband ion beam focusing device based on laser-driven megagauss thermoelectric magnetic fields

    NASA Astrophysics Data System (ADS)

    Albertazzi, B.; d'Humières, E.; Lancia, L.; Dervieux, V.; Antici, P.; Böcker, J.; Bonlie, J.; Breil, J.; Cauble, B.; Chen, S. N.; Feugeas, J. L.; Nakatsutsumi, M.; Nicolaï, P.; Romagnani, L.; Shepherd, R.; Sentoku, Y.; Swantusch, M.; Tikhonchuk, V. T.; Borghesi, M.; Willi, O.; Pépin, H.; Fuchs, J.

    2015-04-01

    Ultra-intense lasers can nowadays routinely accelerate kiloampere ion beams. These unique sources of particle beams could impact many societal (e.g., proton-therapy or fuel recycling) and fundamental (e.g., neutron probing) domains. However, this requires overcoming the beam angular divergence at the source. This has been attempted, either with large-scale conventional setups or with compact plasma techniques that however have the restriction of short (<1 mm) focusing distances or a chromatic behavior. Here, we show that exploiting laser-triggered, long-lasting (>50 ps), thermoelectric multi-megagauss surface magnetic (B)-fields, compact capturing, and focusing of a diverging laser-driven multi-MeV ion beam can be achieved over a wide range of ion energies in the limit of a 5° acceptance angle.

  2. Long-Range Coulomb Effect in Intense Laser-Driven Photoelectron Dynamics

    NASA Astrophysics Data System (ADS)

    Quan, Wei; Hao, Xiaolei; Chen, Yongju; Yu, Shaogang; Xu, Songpo; Wang, Yanlan; Sun, Renping; Lai, Xuanyang; Wu, Chengyin; Gong, Qihuang; He, Xiantu; Liu, Xiaojun; Chen, Jing

    2016-06-01

    In strong field atomic physics community, long-range Coulomb interaction has for a long time been overlooked and its significant role in intense laser-driven photoelectron dynamics eluded experimental observations. Here we report an experimental investigation of the effect of long-range Coulomb potential on the dynamics of near-zero-momentum photoelectrons produced in photo-ionization process of noble gas atoms in intense midinfrared laser pulses. By exploring the dependence of photoelectron distributions near zero momentum on laser intensity and wavelength, we unambiguously demonstrate that the long-range tail of the Coulomb potential (i.e., up to several hundreds atomic units) plays an important role in determining the photoelectron dynamics after the pulse ends.

  3. Long-Range Coulomb Effect in Intense Laser-Driven Photoelectron Dynamics

    PubMed Central

    Quan, Wei; Hao, XiaoLei; Chen, YongJu; Yu, ShaoGang; Xu, SongPo; Wang, YanLan; Sun, RenPing; Lai, XuanYang; Wu, ChengYin; Gong, QiHuang; He, XianTu; Liu, XiaoJun; Chen, Jing

    2016-01-01

    In strong field atomic physics community, long-range Coulomb interaction has for a long time been overlooked and its significant role in intense laser-driven photoelectron dynamics eluded experimental observations. Here we report an experimental investigation of the effect of long-range Coulomb potential on the dynamics of near-zero-momentum photoelectrons produced in photo-ionization process of noble gas atoms in intense midinfrared laser pulses. By exploring the dependence of photoelectron distributions near zero momentum on laser intensity and wavelength, we unambiguously demonstrate that the long-range tail of the Coulomb potential (i.e., up to several hundreds atomic units) plays an important role in determining the photoelectron dynamics after the pulse ends. PMID:27256904

  4. Long-Range Coulomb Effect in Intense Laser-Driven Photoelectron Dynamics.

    PubMed

    Quan, Wei; Hao, XiaoLei; Chen, YongJu; Yu, ShaoGang; Xu, SongPo; Wang, YanLan; Sun, RenPing; Lai, XuanYang; Wu, ChengYin; Gong, QiHuang; He, XianTu; Liu, XiaoJun; Chen, Jing

    2016-01-01

    In strong field atomic physics community, long-range Coulomb interaction has for a long time been overlooked and its significant role in intense laser-driven photoelectron dynamics eluded experimental observations. Here we report an experimental investigation of the effect of long-range Coulomb potential on the dynamics of near-zero-momentum photoelectrons produced in photo-ionization process of noble gas atoms in intense midinfrared laser pulses. By exploring the dependence of photoelectron distributions near zero momentum on laser intensity and wavelength, we unambiguously demonstrate that the long-range tail of the Coulomb potential (i.e., up to several hundreds atomic units) plays an important role in determining the photoelectron dynamics after the pulse ends. PMID:27256904

  5. Flash Kα radiography of laser-driven solid sphere compression for fast ignition

    NASA Astrophysics Data System (ADS)

    Sawada, H.; Lee, S.; Shiroto, T.; Nagatomo, H.; Arikawa, Y.; Nishimura, H.; Ueda, T.; Shigemori, K.; Sunahara, A.; Ohnishi, N.; Beg, F. N.; Theobald, W.; Pérez, F.; Patel, P. K.; Fujioka, S.

    2016-06-01

    Time-resolved compression of a laser-driven solid deuterated plastic sphere with a cone was measured with flash Kα x-ray radiography. A spherically converging shockwave launched by nanosecond GEKKO XII beams was used for compression while a flash of 4.51 keV Ti Kα x-ray backlighter was produced by a high-intensity, picosecond laser LFEX (Laser for Fast ignition EXperiment) near peak compression for radiography. Areal densities of the compressed core were inferred from two-dimensional backlit x-ray images recorded with a narrow-band spherical crystal imager. The maximum areal density in the experiment was estimated to be 87 ± 26 mg/cm2. The temporal evolution of the experimental and simulated areal densities with a 2-D radiation-hydrodynamics code is in good agreement.

  6. New methods for high current fast ion beam production by laser-driven acceleration

    SciTech Connect

    Margarone, D.; Krasa, J.; Prokupek, J.; Velyhan, A.; Laska, L.; Jungwirth, K.; Mocek, T.; Korn, G.; Rus, B.; Torrisi, L.; Gammino, S.; Cirrone, P.; Cutroneo, M.; Romano, F.; Picciotto, A.; Serra, E.; Giuffrida, L.; Mangione, A.; Rosinski, M.; Parys, P.; and others

    2012-02-15

    An overview of the last experimental campaigns on laser-driven ion acceleration performed at the PALS facility in Prague is given. Both the 2 TW, sub-nanosecond iodine laser system and the 20 TW, femtosecond Ti:sapphire laser, recently installed at PALS, are used along our experiments performed in the intensity range 10{sup 16}-10{sup 19} W/cm{sup 2}. The main goal of our studies was to generate high energy, high current ion streams at relatively low laser intensities. The discussed experimental investigations show promising results in terms of maximum ion energy and current density, which make the laser-accelerated ion beams a candidate for new-generation ion sources to be employed in medicine, nuclear physics, matter physics, and industry.

  7. Acceleration of laser-driven ion bunch from double-layer thin foils

    SciTech Connect

    Wang, X.; Liang, E.; Yu, W.; Yu, M. Y.

    2012-05-15

    Generation of monoenergetic ion bunch from a double-layer thin-foil target irradiated by an intense linearly polarized laser pulse is investigated using two-dimensional particle-in-cell simulation. The protons in the front low-density hydrogen target layer accelerated by the space-charge field of the laser-driven hot electrons can penetrate through the high-Z high-mass and high-density ion layer, resulting in an energetic proton bunch. A part of the latter is further accelerated by the space-charge field of the hot electrons in the vacuum behind the high-Z ion layer. With this scheme, quasi-monoenergetic proton bunches can be produced using presently available laser pulses of moderate contrast and duration.

  8. Stable Laser-Driven Electron Beams from a Steady-State-Flow Gas Cell

    SciTech Connect

    Osterhoff, J.; Popp, A.; Karsch, S.; Major, Zs.; Marx, B.; Fuchs, M.; Hoerlein, R.; Gruener, F.; Habs, D.; Krausz, F.; Rowlands-Rees, T. P.; Hooker, S. M.

    2009-01-22

    Quasi-monoenergetic, laser-driven electron beams of up to {approx}200 MeV in energy have been generated from steady-state-flow gas cells [1]. These beams are emitted within a low-divergence cone of 2.1{+-}0.5 mrad FWHM and feature unparalleled shot-to-shot stability in energy (2.5% rms), pointing direction (1.4 mrad rms) and charge (16% rms) owing to a highly reproducible plasma-density profile within the laser-plasma-interaction volume. Laser-wakefield acceleration (LWFA) in gas cells of this type constitutes a simple and reliable source of relativistic electrons with well defined properties, which should allow for applications such as the production of extreme-ultraviolet undulator radiation in the near future.

  9. Efficient quasi-monoenergetic ion beams from laser-driven relativistic plasmas

    SciTech Connect

    Palaniyappan, Sasi; Huang, Chengkun; Gautier, Donald C.; Hamilton, Christopher E.; Santiago, Miguel A.; Kreuzer, Christian; Sefkow, Adam B.; Shah, Rahul C.; Fernández, Juan C.

    2015-12-11

    Table-top laser–plasma ion accelerators have many exciting applications, many of which require ion beams with simultaneous narrow energy spread and high conversion efficiency. However, achieving these requirements has been elusive. We report the experimental demonstration of laser-driven ion beams with narrow energy spread and energies up to 18 MeV per nucleon and ~5% conversion efficiency (that is 4 J out of 80-J laser). Using computer simulations we identify a self-organizing scheme that reduces the ion energy spread after the laser exits the plasma through persisting self-generated plasma electric (~1012 V m-1) and magnetic (~104 T) fields. Furthermore, these results contribute to the development of next generation compact accelerators suitable for many applications such as isochoric heating for ion-fast ignition and producing warm dense matter for basic science.

  10. Biological cell irradiation at ultrahigh dose rate employing laser driven protons

    SciTech Connect

    Doria, D.; Kakolee, K. F.; Kar, S.; and others

    2012-07-09

    The ultrashort duration of laser-driven multi-MeV ion bursts offers the possibility of radiobiological studies at extremely high dose rates. Employing the TARANIS Terawatt laser at Queen's University, the effect of proton irradiation at MeV-range energies on live cells has been investigated at dose rates exceeding 10{sup 9}Gy/s as a single exposure. A clonogenic assay showed consistent lethal effects on V-79 live cells, which, even at these dose rates, appear to be in line with previously published results employing conventional sources. A Relative Biological Effectiveness (RBE) of 1.4{+-}0.2 at 10% survival is estimated from a comparison with a 225 kVp X-ray source.

  11. Particle-in-cell simulations of electron energization in laser-driven magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Lu, San; Lu, Quanming; Guo, Fan; Sheng, Zhengming; Wang, Huanyu; Wang, Shui

    2016-01-01

    Electrons can be energized during laser-driven magnetic reconnection, and the energized electrons form three super-Alfvénic electron jets in the outflow region (Lu et al 2014 New J. Phys. 16 083021). In this paper, by performing two-dimensional particle-in-cell simulations, we find that the electrons can also be significantly energized before magnetic reconnection occurs. When two plasma bubbles with toroidal magnetic fields expand and squeeze each other, the electrons in the magnetic ribbons are energized through betatron acceleration due to the enhancement of the magnetic field, and an electron temperature anisotropy {T}{{e}\\perp }\\gt {T}{{e}| | } develops. Meanwhile, some electrons are trapped and bounced repeatedly between the two expanding/approaching bubbles and get energized through a Fermi-like process. The energization before magnetic reconnection is more significant (or important) than that during magnetic reconnection.

  12. Equation of state measurements of warm dense carbon using laser-driven shock and release technique.

    PubMed

    Falk, K; Gamboa, E J; Kagan, G; Montgomery, D S; Srinivasan, B; Tzeferacos, P; Benage, J F

    2014-04-18

    We present a new approach to equation of state experiments that utilizes a laser-driven shock and release technique combined with spatially resolved x-ray Thomson scattering, radiography, velocity interferometry, and optical pyrometry to obtain independent measurements of pressure, density, and temperature for carbon at warm dense matter conditions. The uniqueness of this approach relies on using a laser to create very high initial pressures to enable a very deep release when the shock moves into a low-density pressure standard. This results in material at near normal solid density and temperatures around 10 eV. The spatially resolved Thomson scattering measurements facilitate a temperature determination of the released material by isolating the scattering signal from a specific region in the target. Our results are consistent with quantum molecular dynamics calculations for carbon at these conditions and are compared to several equation of state models. PMID:24785044

  13. Efficient quasi-monoenergetic ion beams from laser-driven relativistic plasmas.

    PubMed

    Palaniyappan, Sasi; Huang, Chengkun; Gautier, Donald C; Hamilton, Christopher E; Santiago, Miguel A; Kreuzer, Christian; Sefkow, Adam B; Shah, Rahul C; Fernández, Juan C

    2015-01-01

    Table-top laser-plasma ion accelerators have many exciting applications, many of which require ion beams with simultaneous narrow energy spread and high conversion efficiency. However, achieving these requirements has been elusive. Here we report the experimental demonstration of laser-driven ion beams with narrow energy spread and energies up to 18 MeV per nucleon and ∼5% conversion efficiency (that is 4 J out of 80-J laser). Using computer simulations we identify a self-organizing scheme that reduces the ion energy spread after the laser exits the plasma through persisting self-generated plasma electric (∼10(12) V m(-1)) and magnetic (∼10(4) T) fields. These results contribute to the development of next generation compact accelerators suitable for many applications such as isochoric heating for ion-fast ignition and producing warm dense matter for basic science. PMID:26657147

  14. Influence of radiation reaction force on ultraintense laser-driven ion acceleration.

    PubMed

    Capdessus, R; McKenna, P

    2015-05-01

    The role of the radiation reaction force in ultraintense laser-driven ion acceleration is investigated. For laser intensities ∼10(23)W/cm(2), the action of this force on electrons is demonstrated in relativistic particle-in-cell simulations to significantly enhance the energy transfer to ions in relativistically transparent targets, but strongly reduce the ion energy in dense plasma targets. An expression is derived for the revised piston velocity, and hence ion energy, taking account of energy loses to synchrotron radiation generated by electrons accelerated in the laser field. Ion mass is demonstrated to be important by comparing results obtained with proton and deuteron plasma. The results can be verified in experiments with cryogenic hydrogen and deuterium targets. PMID:26066270

  15. Toward high-energy laser-driven ion beams: Nanostructured double-layer targets

    NASA Astrophysics Data System (ADS)

    Passoni, M.; Sgattoni, A.; Prencipe, I.; Fedeli, L.; Dellasega, D.; Cialfi, L.; Choi, Il Woo; Kim, I. Jong; Janulewicz, K. A.; Lee, Hwang Woon; Sung, Jae Hee; Lee, Seong Ku; Nam, Chang Hee

    2016-06-01

    The development of novel target concepts is crucial to make laser-driven acceleration of ion beams suitable for applications. We tested double-layer targets formed of an ultralow density nanostructured carbon layer (˜7 mg/cm 3 , 8 - 12 μ m -thick) deposited on a μ m -thick solid Al foil. A systematic increase in the total number of the accelerated ions (protons and C6 + ) as well as enhancement of both their maximum and average energies was observed with respect to bare solid foil targets. Maximum proton energies up to 30 MeV were recorded. Dedicated three-dimensional particle-in-cell simulations were in remarkable agreement with the experimental results, giving clear indication of the role played by the target nanostructures in the interaction process.

  16. Micro-punching process based on spallation delamination induced by laser driven-flyer

    NASA Astrophysics Data System (ADS)

    Di, Jianke; Zhou, Ming; Li, Jian; Li, Chen; Zhang, Wei; Amoako, George

    2012-01-01

    In this article, we proposed a micro-punching process for microstructure on films based on laser driven-flyer induced spallation delamination phenomenon at the interface between a film and its substrate. To validate such a micro-punching process, a series of experiments were carried out for fabrication of microstructures on Au films coated on K9 glass substrates and polyimide substrate. Results show that through such a punching process, the microstructure on Au films can be fabricated efficiently and the spatial resolution is able to reach micron level. Moreover, we found that this method was more suitable for films coated on soft substrates rather than that coated on brittle substrates due to the additional destruction of the brittle substrate. This micro-punching process has a wide range of potential application in microfluidic devices, biodevices and other MEMS devices.

  17. Thermally generated magnetic fields in laser-driven compressions and explosions

    NASA Technical Reports Server (NTRS)

    Tidman, D. A.

    1975-01-01

    The evolution of thermally generated magnetic fields in a plasma undergoing a nearly spherically symmetric adiabatic compression or expansion is calculated. The analysis is applied to obtain approximate results for the development of magnetic fields in laser-driven compression and explosion of a pellet of nuclear fuel. Localized sources, such as those occurring at composition boundaries in structured pellets or at shock fronts, give stronger fields than those deriving from smoothly distributed asymmetries. Although these fields may approach 10 million G in the late stages of compression, this is not expected to present difficulties for the compression process. Assuming ignition of a nuclear explosion occurs, the sources become much stronger, and values of approximately 10 billion G are obtained at tamper boundaries assuming a 20% departure from spherical symmetry during the explosion.

  18. High-intensity laser-driven proton acceleration enhancement from hydrogen containing ultrathin targets

    SciTech Connect

    Dollar, F.; Reed, S. A.; Matsuoka, T.; Bulanov, S. S.; Chvykov, V.; Kalintchenko, G.; McGuffey, C.; Rousseau, P.; Thomas, A. G. R.; Willingale, L.; Yanovsky, V.; Krushelnick, K.; Maksimchuk, A.; Litzenberg, D. W.

    2013-09-30

    Laser driven proton acceleration experiments from micron and submicron thick targets using high intensity (2 × 10{sup 21} W/cm{sup 2}), high contrast (10{sup −15}) laser pulses show an enhancement of maximum energy when hydrogen containing targets were used instead of non-hydrogen containing. In our experiments, using thin (<1μm) plastic foil targets resulted in maximum proton energies that were consistently 20%–100% higher than when equivalent thickness inorganic targets, including Si{sub 3}N{sub 4} and Al, were used. Proton energies up to 20 MeV were measured with a flux of 10{sup 7} protons/MeV/sr.

  19. Efficient quasi-monoenergetic ion beams from laser-driven relativistic plasmas

    DOE PAGESBeta

    Palaniyappan, Sasi; Huang, Chengkun; Gautier, Donald C.; Hamilton, Christopher E.; Santiago, Miguel A.; Kreuzer, Christian; Sefkow, Adam B.; Shah, Rahul C.; Fernández, Juan C.

    2015-12-11

    Table-top laser–plasma ion accelerators have many exciting applications, many of which require ion beams with simultaneous narrow energy spread and high conversion efficiency. However, achieving these requirements has been elusive. We report the experimental demonstration of laser-driven ion beams with narrow energy spread and energies up to 18 MeV per nucleon and ~5% conversion efficiency (that is 4 J out of 80-J laser). Using computer simulations we identify a self-organizing scheme that reduces the ion energy spread after the laser exits the plasma through persisting self-generated plasma electric (~1012 V m-1) and magnetic (~104 T) fields. Furthermore, these results contributemore » to the development of next generation compact accelerators suitable for many applications such as isochoric heating for ion-fast ignition and producing warm dense matter for basic science.« less

  20. The Effect of Ion Motion on Laser-Driven Plasma Wake in Capillary

    NASA Astrophysics Data System (ADS)

    Zhou, Suyun; Chen, Hui; Li, Yanfang

    2016-01-01

    The effect of ion motion in capillary-guided laser-driven plasma wake is investigated through rebuilding a two-dimensional analytical model. It is shown that laser pulse with the same power can excite more intense wakefield in the capillary of a smaller radius. When laser intensity exceeds a critical value, the effect of ion motion reducing the wakefield rises, which becomes significant with a decrease of capillary radius. This phenomenon can be attributed to plasma ions in smaller capillary obtaining more energy from the plasma wake. The dependence of the difference value between maximal scalar potential of wake for two cases of ion rest and ion motion on the radius of the capillary is discussed. supported by National Natural Science Foundation of China (No. 11247016), the Natural Science Foundation of Jiangxi Province, China (Nos. 2014ZBAB202001 and 20151BAB212010), and the Science Foundation for Youths of the Jiangxi Education Committee of China (No. GJJ14224)

  1. Laser-driven flyer impact experiments at the LULI 2000 laser facility

    NASA Astrophysics Data System (ADS)

    Ozaki, N.; Koenig, M.; Benuzzi-Mounaix, A.; Vinci, T.; Ravasio, A.; Esposito, M.; Lepape, S.; Henry, E.; Hüser, G.; Tanaka, K. A.; Nazarov, W.; Nagai, K.; Yoshida, M.

    2006-06-01

    New laser-driven flyer impact experiments have been performed at the LULI laboratory. In these experiments, three types of targets (single Al flyer, multi-layered, and foam-buffered high-Z metal) were used. Impacted conditions in fused quartz were measured with rear-side (two VISARs and SOP) and transverse diagnostics (shadowgraph). In the foam-buffered target, Ta foil was accelerated up to a velocity of 55 km/s. Shock wave accelerated in fused quartz by an Al flyer impact was generated, and the shock wave passing a distinct boundary to a conductive state was directly observed. This method is a way to create unique conditions within the EOS diagram of material.

  2. Perspectives for neutron and gamma spectroscopy in high power laser driven experiments at ELI-NP

    NASA Astrophysics Data System (ADS)

    Negoita, F.; Gugiu, M.; Petrascu, H.; Petrone, C.; Pietreanu, D.; Fuchs, J.; Chen, S.; Higginson, D.; Vassura, L.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Antici, P.; Balabanski, D.; Balascuta, S.; Cernaianu, M.; Dancus, I.; Gales, S.; Neagu, L.; Petcu, C.; Risca, M.; Toma, M.; Turcu, E.; Ursescu, D.

    2015-02-01

    The measurement of energy spectra of neutrons and gamma rays emitted by nuclei, together with charge particles spectroscopy, are the main tools for understanding nuclear phenomena occurring also in high power laser driven experiments. However, the large number of particles emitted in a very short time, in particular the strong X-rays flash produced in laser-target interaction, impose adaptation of technique currently used in nuclear physics experiment at accelerator based facilities. These aspects are discussed (Section 1) in the context of proposed studies at high power laser system of ELI-NP. Preliminary results from two experiments performed at Titan (LLNL) and ELFIE (LULI) facilities using plastic scintillators for neutron detection (Section 2) and LaBr3(Ce) scintillators for gamma detection (Section 3) are presented demonstrating the capabilities and the limitations of the employed methods. Possible improvements of these spectroscopic methods and their proposed implementation at ELI-NP will be discussed as well in the last section.

  3. Studies of laser-driven isentropic compression of iron in the context of geophysics

    NASA Astrophysics Data System (ADS)

    Mazevet, S.; Huser, G.; Occelli, F.; Festa, F.; Brambrink, E.; Amadou, N.; Vinci, T.; Diziere, A.; Benuzzi-Mounaix, A.; Koenig, M.; Guyot, F.; Morard, G.; Myanishi, K.; Kodama, R.; Ozaki, N.; de Resseguier, Th.

    2010-11-01

    The study of iron using dynamic compression paths yielding parameters different from that achieved on the principal Hugoniot might allow to access parameters relevant for the understanding of the solid-liquid phase transition in the Earth core (330 GPa, 5000 K). Beside the geophysical interest, dynamic compression allows to study the dynamics of the alpha-epsilon phase transition, as compression characteristic times are comparable with reaction kinetics. We have performed laser-driven ramp compression experiments on iron samples using the LULI laser facility. Different pressure ramp shapes and target samples will be presented. These results are also important to design future experiments using very large-scale facilities, which would allow to explore pressure-temperature conditions relevant to terrestrial-type exoplanets, which were recently discovered.

  4. A compact broadband ion beam focusing device based on laser-driven megagauss thermoelectric magnetic fields.

    PubMed

    Albertazzi, B; d'Humières, E; Lancia, L; Dervieux, V; Antici, P; Böcker, J; Bonlie, J; Breil, J; Cauble, B; Chen, S N; Feugeas, J L; Nakatsutsumi, M; Nicolaï, P; Romagnani, L; Shepherd, R; Sentoku, Y; Swantusch, M; Tikhonchuk, V T; Borghesi, M; Willi, O; Pépin, H; Fuchs, J

    2015-04-01

    Ultra-intense lasers can nowadays routinely accelerate kiloampere ion beams. These unique sources of particle beams could impact many societal (e.g., proton-therapy or fuel recycling) and fundamental (e.g., neutron probing) domains. However, this requires overcoming the beam angular divergence at the source. This has been attempted, either with large-scale conventional setups or with compact plasma techniques that however have the restriction of short (<1 mm) focusing distances or a chromatic behavior. Here, we show that exploiting laser-triggered, long-lasting (>50 ps), thermoelectric multi-megagauss surface magnetic (B)-fields, compact capturing, and focusing of a diverging laser-driven multi-MeV ion beam can be achieved over a wide range of ion energies in the limit of a 5° acceptance angle. PMID:25933857

  5. Focusing dynamics of high-energy density, laser-driven ion beams.

    PubMed

    Chen, S N; d'Humières, E; Lefebvre, E; Romagnani, L; Toncian, T; Antici, P; Audebert, P; Brambrink, E; Cecchetti, C A; Kudyakov, T; Pipahl, A; Sentoku, Y; Borghesi, M; Willi, O; Fuchs, J

    2012-02-01

    The dynamics of the focusing of laser-driven ion beams produced from concave solid targets was studied. Most of the ion beam energy is observed to converge at the center of the cylindrical targets with a spot diameter of 30  μm, which can be very beneficial for applications requiring high beam energy densities. Also, unbalanced laser irradiation does not compromise the focusability of the beam. However, significant filamentation occurs during the focusing, potentially limiting the localization of the energy deposition region by these beams at focus. These effects could impact the applicability of such high-energy density beams for applications, e.g., in proton-driven fast ignition. PMID:22400936

  6. Efficient quasi-monoenergetic ion beams from laser-driven relativistic plasmas

    NASA Astrophysics Data System (ADS)

    Palaniyappan, Sasi; Huang, Chengkun; Gautier, Donald C.; Hamilton, Christopher E.; Santiago, Miguel A.; Kreuzer, Christian; Sefkow, Adam B.; Shah, Rahul C.; Fernández, Juan C.

    2015-12-01

    Table-top laser-plasma ion accelerators have many exciting applications, many of which require ion beams with simultaneous narrow energy spread and high conversion efficiency. However, achieving these requirements has been elusive. Here we report the experimental demonstration of laser-driven ion beams with narrow energy spread and energies up to 18 MeV per nucleon and ~5% conversion efficiency (that is 4 J out of 80-J laser). Using computer simulations we identify a self-organizing scheme that reduces the ion energy spread after the laser exits the plasma through persisting self-generated plasma electric (~1012 V m-1) and magnetic (~104 T) fields. These results contribute to the development of next generation compact accelerators suitable for many applications such as isochoric heating for ion-fast ignition and producing warm dense matter for basic science.

  7. Ultrafast phase contrast imaging of laser driven shocks using betatron X-rays

    NASA Astrophysics Data System (ADS)

    Chapman, D. J.; Rutherford, M. E.; White, T. G.; Eakins, D. E.; Wood, J. C.; Poder, K.; Lopes, N. C.; Bryant, J. S. J.; Mangles, S. P. D.; Najmudin, Z.; Cole, J. S.; Albert, F.; Pollack, B. B.; Behm, K. T.; Zhao, Z.; Thomas, A. G. R.; Krushelnick, K.; Schumaker, W.; Glenzer, S.

    2015-06-01

    Bright, high-energy photon sources, such as synchrotrons and more recently the new generation of X-ray free-electron lasers, offer the attractive combination of high brilliance, short pulse duration and high-energy X-rays. Betatron X-rays produced within a laser-plasma wakefield accelerator provide an exciting complementary energetic photon source to these large scale facilities. We describe the first proof-of-principle experiments imaging shock-front evolution in laser driven targets using wakefield betatron X-rays. These pioneering experiments were performed on the 400TW Gemini laser at the Rutherford Appleton Laboratory, UK. Shock waves were driven into silicon wafers along the [100] direction, and stroboscopically imaged perpendicular to the shock propagation direction using a ~ 40 fs betatron X-ray pulse. These initial results showcase a promising, potentially table top sized X-ray source suitable for probing the response of materials under extreme condition.

  8. Reflective optical probing of laser-driven plasmas at the rear surface of solid targets

    NASA Astrophysics Data System (ADS)

    Metzkes, J.; Zeil, K.; Kraft, S. D.; Rehwald, M.; Cowan, T. E.; Schramm, U.

    2016-03-01

    In this paper, a reflective optical pump-probe technique for laser-driven plasmas at solid density target surfaces is presented. The technique is termed high depth-of-field time-resolved microscopy and it exploits the angular redistribution of the probe beam intensity after the probe’s reflection from an expanded and hence non-planar iso-density surface in the plasma. The main application of the robust technique, which uses simple imaging of the probe beam, is the spatio-temporal resolution of the plasma formation and expansion at the target rear surface. Analytic and numerical modeling of the experimental setup are applied for the analysis of the experimental results. The relevance and potential of the optical plasma probing method is highlighted by the application to targets of different geometries, helping to understand the target shape-related differences in the ion acceleration performance.

  9. Characterization of the ELIMED Permanent Magnets Quadrupole system prototype with laser-driven proton beams

    NASA Astrophysics Data System (ADS)

    Schillaci, F.; Pommarel, L.; Romano, F.; Cuttone, G.; Costa, M.; Giove, D.; Maggiore, M.; Russo, A. D.; Scuderi, V.; Malka, V.; Vauzour, B.; Flacco, A.; Cirrone, G. A. P.

    2016-07-01

    Laser-based accelerators are gaining interest in recent years as an alternative to conventional machines [1]. In the actual ion acceleration scheme, energy and angular spread of the laser-driven beams are the main limiting factors for beam applications and different solutions for dedicated beam-transport lines have been proposed [2,3]. In this context a system of Permanent Magnet Quadrupoles (PMQs) has been realized [2] by INFN-LNS (Laboratori Nazionali del Sud of the Instituto Nazionale di Fisica Nucleare) researchers, in collaboration with SIGMAPHI company in France, to be used as a collection and pre-selection system for laser driven proton beams. This system is meant to be a prototype to a more performing one [3] to be installed at ELI-Beamlines for the collection of ions. The final system is designed for protons and carbons up to 60 MeV/u. In order to validate the design and the performances of this large bore, compact, high gradient magnetic system prototype an experimental campaign have been carried out, in collaboration with the group of the SAPHIR experimental facility at LOA (Laboratoire d'Optique Appliquée) in Paris using a 200 TW Ti:Sapphire laser system. During this campaign a deep study of the quadrupole system optics has been performed, comparing the results with the simulation codes used to determine the setup of the PMQ system and to track protons with realistic TNSA-like divergence and spectrum. Experimental and simulation results are good agreement, demonstrating the possibility to have a good control on the magnet optics. The procedure used during the experimental campaign and the most relevant results are reported here.

  10. Laser-driven x-ray and neutron source development for industrial applications of plasma accelerators

    NASA Astrophysics Data System (ADS)

    Brenner, C. M.; Mirfayzi, S. R.; Rusby, D. R.; Armstrong, C.; Alejo, A.; Wilson, L. A.; Clarke, R.; Ahmed, H.; Butler, N. M. H.; Haddock, D.; Higginson, A.; McClymont, A.; Murphy, C.; Notley, M.; Oliver, P.; Allott, R.; Hernandez-Gomez, C.; Kar, S.; McKenna, P.; Neely, D.

    2016-01-01

    Pulsed beams of energetic x-rays and neutrons from intense laser interactions with solid foils are promising for applications where bright, small emission area sources, capable of multi-modal delivery are ideal. Possible end users of laser-driven multi-modal sources are those requiring advanced non-destructive inspection techniques in industry sectors of high value commerce such as aerospace, nuclear and advanced manufacturing. We report on experimental work that demonstrates multi-modal operation of high power laser-solid interactions for neutron and x-ray beam generation. Measurements and Monte Carlo radiation transport simulations show that neutron yield is increased by a factor ~2 when a 1 mm copper foil is placed behind a 2 mm lithium foil, compared to using a 2 cm block of lithium only. We explore x-ray generation with a 10 picosecond drive pulse in order to tailor the spectral content for radiography with medium density alloy metals. The impact of using  >1 ps pulse duration on laser-accelerated electron beam generation and transport is discussed alongside the optimisation of subsequent bremsstrahlung emission in thin, high atomic number target foils. X-ray spectra are deconvolved from spectrometer measurements and simulation data generated using the GEANT4 Monte Carlo code. We also demonstrate the unique capability of laser-driven x-rays in being able to deliver single pulse high spatial resolution projection imaging of thick metallic objects. Active detector radiographic imaging of industrially relevant sample objects with a 10 ps drive pulse is presented for the first time, demonstrating that features of 200 μm size are resolved when projected at high magnification.

  11. Laser-driven electron beamlines generated by coupling laser-plasma sources with conventional transport systems

    SciTech Connect

    Antici, P.; Benedetti, C.; Lancia, L.; Migliorati, M.; Mostacci, A.; Palumbo, L.

    2012-08-15

    Laser-driven electron beamlines are receiving increasing interest from the particle accelerator community. In particular, the high initial energy, low emittance, and high beam current of the plasma based electron source potentially allow generating much more compact and bright particle accelerators than what conventional accelerator technology can achieve. Using laser-generated particles as injectors for generating beamlines could significantly reduce the size and cost of accelerator facilities. Unfortunately, several features of laser-based particle beams need still to be improved before considering them for particle beamlines and thus enable the use of plasma-driven accelerators for the multiple applications of traditional accelerators. Besides working on the plasma source itself, a promising approach to shape the laser-generated beams is coupling them with conventional accelerator elements in order to benefit from both a versatile electron source and a controllable beam. In this paper, we perform start-to-end simulations to generate laser-driven beamlines using conventional accelerator codes and methodologies. Starting with laser-generated electrons that can be obtained with established multi-hundred TW laser systems, we compare different options to capture and transport the beams. This is performed with the aim of providing beamlines suitable for potential applications, such as free electron lasers. In our approach, we have analyzed which parameters are critical at the source and from there evaluated different ways to overcome these issues using conventional accelerator elements and methods. We show that electron driven beamlines are potentially feasible, but exploiting their full potential requires extensive improvement of the source parameters or innovative technological devices for their transport and capture.

  12. Laser-driven electron beam acceleration and future application to compact light sources

    SciTech Connect

    Hafz, N.; Jeong, T. M.; Lee, S. K.; Pae, K. H.; Sung, J. H.; Choi, I. W.; Yu, T. J.; Lee, J.; Jeong, Y. U.

    2009-07-25

    Laser-driven plasma accelerators are gaining much attention by the advanced accelerator community due to the potential these accelerators hold in miniaturizing future high-energy and medium-energy machines. In the laser wakefield accelerator (LWFA), the ponderomotive force of an ultrashort high intensity laser pulse excites a longitudinal plasma wave or bubble. Due to huge charge separation, electric fields created in the plasma bubble can be several orders of magnitude higher than those available in conventional microwave and RF-based accelerator facilities which are limited (up to approx100 MV/m) by material breakdown. Therefore, if an electron bunch is injected into the bubble in phase with its field, it will gain relativistic energies within an extremely short distance. Here, in the LWFA we show the generation of high-quality and high-energy electron beams up to the GeV-class within a few millimeters of gas-jet plasmas irradiated by tens of terawatt ultrashort laser pulses. Thus we realize approximately four orders of magnitude acceleration gradients higher than available by conventional technology. As a practical application of the stable high-energy electron beam generation, we are planning on injecting the electron beams into a few-meters long conventional undulator in order to realize compact X-ray synchrotron (immediate) and FEL (future) light sources. Stable laser-driven electron beam and radiation devices will surely open a new era in science, medicine and technology and will benefit a larger number of users in those fields.

  13. The progress in the laser-driven proton acceleration experiment JAEA with table-tip Ti:Sappire laser system

    NASA Astrophysics Data System (ADS)

    Nishiuchi, M.; Ogura, K.; Pirozhkov, A. S.; Tanimoto, T.; Yogo, A.; Sakaki, H.; Hori, T.; Fukuda, Y.; Kanasaki, M.; Sagisaka, A.; Tampo, M.; Kiriyama, H.; Shimomura, T.; Kondo, K.; Kawanishi, S.; Brenner, C.; Neely, D.

    2011-05-01

    This paper presents the experimental investigation of laser-driven proton acceleration using a table top Ti:Sapphire laser system interacting with the thin-foil targets during the course of medical application of the laser-driven proton beam. The proton beam with maximum energy of upto 14~MeV is generated in 60 TW mode. The number of protons at ~10 MeV is estimated to be over 105 proton/sr/MeV/shot with beam having half divergence angle of 5~degree. If 10 Hz operation is assumed 2 Gy dose is possible to irradiate during 10 min onto a ~1 mm tumor just under the skin. In contrast to the previous condition of our apparatus with which we demonstrated the DNA double-strand breaking by irradiating the laser-driven proton beam onto the human cancer cells in-vitro test, the result reported here has significant meaning in the sense that pre-clinical in-vivo test can be started by irradiating the laser-driven proton beam onto the skin of the mouse, which is unavoidable step before the real radiation therapy.

  14. Experimental Results on the First Short Pulse Laser Driven Neutron Source Powerful Enough For Applications In Radiography

    NASA Astrophysics Data System (ADS)

    Guler, Nevzat

    2012-10-01

    Short pulse laser driven neutron source can be a compact and relatively cheap way to produce neutrons with energies in excess of 10 MeV. It is based on short pulse laser driven ions interacting with a converter material to produce neutrons via separation or breakup mechanisms. Previous research on the short pulse laser driven ion acceleration has mainly concentrated on surface acceleration mechanisms, which typically yield isotropic emission of neutrons from the converter. Recent experiments performed with a high contrast laser at TRIDENT facility at LANL demonstrated laser driven ion acceleration mechanism based on the concept of relativistic transparency. This produced an intense beam of high energy (up to 80 MeV) deuterons directed into a Be converter to produce a forward peaked neutron flux with a record yield, on the order of 4.4x10^9 n/sr. The produced neutron beam had a pulse duration less than a nanosecond and an energy range between 2-80 MeV, peaking around 12 MeV. The neutrons in the energy range of 2.5 to 15 MeV were selected by the gated neutron imager to radiograph tungsten blocks of different thicknesses. We will present the results from the two acceleration mechanisms and the first short pulse laser generated neutron radiograph.

  15. Utilizing a Low-Cost, Laser-Driven Interactive System (LaDIS) to Improve Learning in Developing Rural Regions

    ERIC Educational Resources Information Center

    Liou, Wei-Kai; Chang, Chun-Yen

    2014-01-01

    This study proposes an innovation Laser-Driven Interactive System (LaDIS), utilizing general IWBs (Interactive Whiteboard) didactics, to support student learning for rural and developing regions. LaDIS is a system made to support traditional classroom practices between an instructor and a group of students. This invention effectively transforms a…

  16. Frequency sweep rates of rising tone electromagnetic ion cyclotron waves: Comparison between nonlinear theory and Cluster observation

    SciTech Connect

    He, Zhaoguo; Zong, Qiugang Wang, Yongfu; Liu, Siqing; Lin, Ruilin; Shi, Liqin

    2014-12-15

    Resonant pitch angle scattering by electromagnetic ion cyclotron (EMIC) waves has been suggested to account for the rapid loss of ring current ions and radiation belt electrons. For the rising tone EMIC wave (classified as triggered EMIC emission), its frequency sweep rate strongly affects the efficiency of pitch-angle scattering. Based on the Cluster observations, we analyze three typical cases of rising tone EMIC waves. Two cases locate at the nightside (22.3 and 22.6 magnetic local time (MLT)) equatorial region and one case locates at the duskside (18MLT) higher magnetic latitude (λ = –9.3°) region. For the three cases, the time-dependent wave amplitude, cold electron density, and cold ion density ratio are derived from satellite data; while the ambient magnetic field, thermal proton perpendicular temperature, and the wave spectral can be directly provided by observation. These parameters are input into the nonlinear wave growth model to simulate the time-frequency evolutions of the rising tones. The simulated results show good agreements with the observations of the rising tones, providing further support for the previous finding that the rising tone EMIC wave is excited through the nonlinear wave growth process.

  17. Efficient calculation of cosmological neutrino clustering in the non-linear regime

    NASA Astrophysics Data System (ADS)

    Archidiacono, Maria; Hannestad, Steen

    2016-06-01

    We study in detail how neutrino perturbations can be followed in linear theory by using only terms up to l=2 in the Boltzmann hierarchy. We provide a new approximation to the third moment and demonstrate that the neutrino power spectrum can be calculated to a precision of better than ~ 5% for masses up to ~ 1 eV and k lesssim 10 h/Mpc. The matter power spectrum can be calculated far more precisely and typically at least a factor of a few better than with existing approximations. We then proceed to study how the neutrino power spectrum can be reliably calculated even in the non-linear regime by using the non-linear gravitational potential, sourced by dark matter overdensities, as it is derived from semi-analytic methods based on N-body simulations in the Boltzmann evolution hierarchy. Our results agree extremely well with results derived from N-body simulations that include cold dark matter and neutrinos as independent particles with different properties.

  18. Propagation of Laser-Driven Relativistic Electron Beam inside Solid Dielectric

    NASA Astrophysics Data System (ADS)

    Sarkisov, G. S.; Jobe, D.; Spielman, R.; Ivanov, V. V.; Leblanc, P.; Sentoku, Y.; Yates, K.; Wiewior, P.; Bychenkov, V. Yu.

    2011-10-01

    Laser probing diagnostics shadowgraphy, interferometry and polarimetry was used for comprehensive characterization of ionization wave dynamics inside glass target induced by laser-driven relativistic electron beam. Experiment was done using 50-TW Leopard laser at University of Nevada Reno. It has been shown that for laser flax ~2 ×1018W/cm2 hemispheric ionization wave propagates with c/3 speed has smooth electron density distribution, absorbing probing green beam in 2-10 times. Maximum of free-electron density inside glass target is ~2x1019cm-3, which correspond to ionization ~0.1%. Magnetic and electric fields do not exceed ~15 kG and ~1 MV/cm. Electron temperature has hot-ring structure with maximum 0.1-0.5 eV. The topology of the interference phase shift shows the signature of the ``fountain effect'', a narrow electron beam that fans out from the propagation axis and heads back to the target surface. Two-dimensional PIC-simulations demonstrate radial spreading of fast electrons by self-consistent electrostatic fields. The very low ionization, ~0.1%, observed after the heating pulse suggests a fast recombination at the sub-ps time scale. Work was supported by the DOE/NNSA under UNR grant DE-FC52-06NA27616 and grant DE-PS02-08ER08-16.

  19. Quantitative X-ray phase-contrast microtomography from a compact laser-driven betatron source

    PubMed Central

    Wenz, J.; Schleede, S.; Khrennikov, K.; Bech, M.; Thibault, P.; Heigoldt, M.; Pfeiffer, F.; Karsch, S.

    2015-01-01

    X-ray phase-contrast imaging has recently led to a revolution in resolving power and tissue contrast in biomedical imaging, microscopy and materials science. The necessary high spatial coherence is currently provided by either large-scale synchrotron facilities with limited beamtime access or by microfocus X-ray tubes with rather limited flux. X-rays radiated by relativistic electrons driven by well-controlled high-power lasers offer a promising route to a proliferation of this powerful imaging technology. A laser-driven plasma wave accelerates and wiggles electrons, giving rise to a brilliant keV X-ray emission. This so-called betatron radiation is emitted in a collimated beam with excellent spatial coherence and remarkable spectral stability. Here we present a phase-contrast microtomogram of a biological sample using betatron X-rays. Comprehensive source characterization enables the reconstruction of absolute electron densities. Our results suggest that laser-based X-ray technology offers the potential for filling the large performance gap between synchrotron- and current X-ray tube-based sources. PMID:26189811

  20. Nonthermal Electron Energization from Magnetic Reconnection in Laser-Driven Plasmas.

    PubMed

    Totorica, Samuel R; Abel, Tom; Fiuza, Frederico

    2016-03-01

    The possibility of studying nonthermal electron energization in laser-driven plasma experiments of magnetic reconnection is studied using two- and three-dimensional particle-in-cell simulations. It is demonstrated that nonthermal electrons with energies more than an order of magnitude larger than the initial thermal energy can be produced in plasma conditions currently accessible in the laboratory. Electrons are accelerated by the reconnection electric field, being injected at varied distances from the X points, and in some cases trapped in plasmoids, before escaping the finite-sized system. Trapped electrons can be further energized by the electric field arising from the motion of the plasmoid. This acceleration gives rise to a nonthermal electron component that resembles a power-law spectrum, containing up to ∼8% of the initial energy of the interacting electrons and ∼24% of the initial magnetic energy. Estimates of the maximum electron energy and of the plasma conditions required to observe suprathermal electron acceleration are provided, paving the way for a new platform for the experimental study of particle acceleration induced by reconnection. PMID:26991182

  1. Quantitative X-ray phase-contrast microtomography from a compact laser-driven betatron source

    NASA Astrophysics Data System (ADS)

    Wenz, J.; Schleede, S.; Khrennikov, K.; Bech, M.; Thibault, P.; Heigoldt, M.; Pfeiffer, F.; Karsch, S.

    2015-07-01

    X-ray phase-contrast imaging has recently led to a revolution in resolving power and tissue contrast in biomedical imaging, microscopy and materials science. The necessary high spatial coherence is currently provided by either large-scale synchrotron facilities with limited beamtime access or by microfocus X-ray tubes with rather limited flux. X-rays radiated by relativistic electrons driven by well-controlled high-power lasers offer a promising route to a proliferation of this powerful imaging technology. A laser-driven plasma wave accelerates and wiggles electrons, giving rise to a brilliant keV X-ray emission. This so-called betatron radiation is emitted in a collimated beam with excellent spatial coherence and remarkable spectral stability. Here we present a phase-contrast microtomogram of a biological sample using betatron X-rays. Comprehensive source characterization enables the reconstruction of absolute electron densities. Our results suggest that laser-based X-ray technology offers the potential for filling the large performance gap between synchrotron- and current X-ray tube-based sources.

  2. Laser-driven, magnetized quasi-perpendicular collisionless shocks on the Large Plasma Devicea)

    NASA Astrophysics Data System (ADS)

    Schaeffer, D. B.; Everson, E. T.; Bondarenko, A. S.; Clark, S. E.; Constantin, C. G.; Vincena, S.; Van Compernolle, B.; Tripathi, S. K. P.; Winske, D.; Gekelman, W.; Niemann, C.

    2014-05-01

    The interaction of a laser-driven super-Alfvénic magnetic piston with a large, preformed magnetized ambient plasma has been studied by utilizing a unique experimental platform that couples the Raptor kJ-class laser system [Niemann et al., J. Instrum. 7, P03010 (2012)] to the Large Plasma Device [Gekelman et al., Rev. Sci. Instrum. 62, 2875 (1991)] at the University of California, Los Angeles. This platform provides experimental conditions of relevance to space and astrophysical magnetic collisionless shocks and, in particular, allows a detailed study of the microphysics of shock formation, including piston-ambient ion collisionless coupling. An overview of the platform and its capabilities is given, and recent experimental results on the coupling of energy between piston and ambient ions and the formation of collisionless shocks are presented and compared to theoretical and computational work. In particular, a magnetosonic pulse consistent with a low-Mach number collisionless shock is observed in a quasi-perpendicular geometry in both experiments and simulations.

  3. Laser-driven, magnetized quasi-perpendicular collisionless shocks on the Large Plasma Device

    SciTech Connect

    Schaeffer, D. B. Everson, E. T.; Bondarenko, A. S.; Clark, S. E.; Constantin, C. G.; Vincena, S.; Van Compernolle, B.; Tripathi, S. K. P.; Gekelman, W.; Niemann, C.; Winske, D.

    2014-05-15

    The interaction of a laser-driven super-Alfvénic magnetic piston with a large, preformed magnetized ambient plasma has been studied by utilizing a unique experimental platform that couples the Raptor kJ-class laser system [Niemann et al., J. Instrum. 7, P03010 (2012)] to the Large Plasma Device [Gekelman et al., Rev. Sci. Instrum. 62, 2875 (1991)] at the University of California, Los Angeles. This platform provides experimental conditions of relevance to space and astrophysical magnetic collisionless shocks and, in particular, allows a detailed study of the microphysics of shock formation, including piston-ambient ion collisionless coupling. An overview of the platform and its capabilities is given, and recent experimental results on the coupling of energy between piston and ambient ions and the formation of collisionless shocks are presented and compared to theoretical and computational work. In particular, a magnetosonic pulse consistent with a low-Mach number collisionless shock is observed in a quasi-perpendicular geometry in both experiments and simulations.

  4. Preferential enhancement of laser-driven carbon ion acceleration from optimized nanostructured surfaces.

    PubMed

    Dalui, Malay; Wang, W-M; Trivikram, T Madhu; Sarkar, Subhrangsu; Sarkar, Subhrangshu; Tata, Sheroy; Jha, J; Ayyub, P; Sheng, Z M; Krishnamurthy, M

    2015-01-01

    High-intensity ultrashort laser pulses focused on metal targets readily generate hot dense plasmas which accelerate ions efficiently and can pave way to compact table-top accelerators. Laser-driven ion acceleration studies predominantly focus on protons, which experience the maximum acceleration owing to their highest charge-to-mass ratio. The possibility of tailoring such schemes for the preferential acceleration of a particular ion species is very much desired but has hardly been explored. Here, we present an experimental demonstration of how the nanostructuring of a copper target can be optimized for enhanced carbon ion acceleration over protons or Cu-ions. Specifically, a thin (≈ 0.25 μm) layer of 25-30 nm diameter Cu nanoparticles, sputter-deposited on a polished Cu-substrate, enhances the carbon ion energy by about 10-fold at a laser intensity of 1.2 × 10(18)  W/cm(2). However, particles smaller than 20 nm have an adverse effect on the ion acceleration. Particle-in-cell simulations provide definite pointers regarding the size of nanoparticles necessary for maximizing the ion acceleration. The inherent contrast of the laser pulse is found to play an important role in the species selective ion acceleration. PMID:26153048

  5. Overview of laser-driven generation of electron-positron beams

    NASA Astrophysics Data System (ADS)

    Sarri, G.; Dieckmann, M. E.; Kourakis, I.; di Piazza, A.; Reville, B.; Keitel, C. H.; Zepf, M.

    2015-08-01

    Electron-positron (e-p) plasmas are widely thought to be emitted, in the form of ultra-relativistic winds or collimated jets, by some of the most energetic or powerful objects in the Universe, such as black-holes, pulsars, and quasars. These phenomena represent an unmatched astrophysical laboratory to test physics at its limit and, given their immense distance from Earth (some even farther than several billion light years), they also provide a unique window on the very early stages of our Universe. However, due to such gigantic distances, their properties are only inferred from the indirect interpretation of their radiative signatures and from matching numerical models: their generation mechanism and dynamics still pose complicated enigmas to the scientific community. Small-scale reproductions in the laboratory would represent a fundamental step towards a deeper understanding of this exotic state of matter. Here we present recent experimental results concerning the laser-driven production of ultra-relativistic e-p beams. In particular, we focus on the possibility of generating beams that present charge neutrality and that allow for collective effects in their dynamics, necessary ingredients for the testing pair-plasma physics in the laboratory. A brief discussion of the analytical and numerical modelling of the dynamics of these plasmas is also presented in order to provide a summary of the novel plasma physics that can be accessed with these objects. Finally, general considerations on the scalability of laboratory plasmas up to astrophysical scenarios are given.

  6. Towards controlled flyer acceleration by a laser-driven mini flyer

    NASA Astrophysics Data System (ADS)

    Yu, Hyeonju; Fedotov, Vitalij; Baek, Wonkye; Yoh, Jack J.

    2014-06-01

    A laser driven flyer (LDF) system is designed to blast off a very small, thin flyer plate for impact on a target. When a Nd:YAG laser beam is focused through a transparent substrate onto thin metal, a fraction of the metal is ablated. The blow-off products being contained between the substrate and the flyer make the remaining thin film launch as a separate flyer. Some energy of the laser beam is lost by reflection at the boundary between substrate and metal because of the high reflectivity. By using a proper metal of high absorptance at 1.064 μm wavelength, the laser coupling to the flyer would define the system efficiency of a launch system. An effort is presented here to improve the coupling results in the enhancement of the flyer velocity for a given pulse energy. An optimum energy conversion between laser energy and kinetic energy of the flyer is achieved through a black paint coating technique as opposed to a more conventional means of a multi-layered approach requiring electron beaming or magnetron sputtering that are rather expensive and time consuming. The mini flyer flown under 1.4 km/s showed a controlled flight trajectory without fragmentation, suggesting that performance of this simple system is competitive to if not better than other attempts by the multi-layered LDF systems.

  7. Preferential enhancement of laser-driven carbon ion acceleration from optimized nanostructured surfaces

    PubMed Central

    Dalui, Malay; Wang, W.-M.; Trivikram, T. Madhu; Sarkar, Subhrangshu; Tata, Sheroy; Jha, J.; Ayyub, P.; Sheng, Z. M.; Krishnamurthy, M.

    2015-01-01

    High-intensity ultrashort laser pulses focused on metal targets readily generate hot dense plasmas which accelerate ions efficiently and can pave way to compact table-top accelerators. Laser-driven ion acceleration studies predominantly focus on protons, which experience the maximum acceleration owing to their highest charge-to-mass ratio. The possibility of tailoring such schemes for the preferential acceleration of a particular ion species is very much desired but has hardly been explored. Here, we present an experimental demonstration of how the nanostructuring of a copper target can be optimized for enhanced carbon ion acceleration over protons or Cu-ions. Specifically, a thin (≈0.25 μm) layer of 25–30 nm diameter Cu nanoparticles, sputter-deposited on a polished Cu-substrate, enhances the carbon ion energy by about 10-fold at a laser intensity of 1.2×1018  W/cm2. However, particles smaller than 20 nm have an adverse effect on the ion acceleration. Particle-in-cell simulations provide definite pointers regarding the size of nanoparticles necessary for maximizing the ion acceleration. The inherent contrast of the laser pulse is found to play an important role in the species selective ion acceleration. PMID:26153048

  8. Propagation of a laser-driven relativistic electron beam inside a solid dielectric.

    PubMed

    Sarkisov, G S; Ivanov, V V; Leblanc, P; Sentoku, Y; Yates, K; Wiewior, P; Chalyy, O; Astanovitskiy, A; Bychenkov, V Yu; Jobe, D; Spielman, R B

    2012-09-01

    Laser probe diagnostics: shadowgraphy, interferometry, and polarimetry were used for a comprehensive characterization of ionization wave dynamics inside a glass target induced by a laser-driven, relativistic electron beam. Experiments were done using the 50-TW Leopard laser at the University of Nevada, Reno. We show that for a laser flux of ∼2 × 10(18) W/cm2 a hemispherical ionization wave propagates at c/3 for 10 ps and has a smooth electron-density distribution. The maximum free-electron density inside the glass target is ∼2 × 10(19) cm-3, which corresponds to an ionization level of ∼0.1%. Magnetic fields and electric fields do not exceed ∼15 kG and ∼1 MV/cm, respectively. The electron temperature has a hot, ringlike structure with a maximum of ∼0.7 eV. The topology of the interference phase shift shows the signature of the "fountain effect", a narrow electron beam that fans out from the propagation axis and heads back to the target surface. Two-dimensional particle-in-cell (PIC) computer simulations demonstrate radial spreading of fast electrons by self-consistent electrostatic fields driven by laser. The very low ionization observed after the laser heating pulse suggests a fast recombination on the sub-ps time scale. PMID:23031038

  9. Cost reduction study for the LANL KrF laser-driven LMF design

    SciTech Connect

    Not Available

    1989-10-27

    This report is in fulfillment of the deliverable requirements for the optical components portions of the LANL-KrF Laser-Driven LMF Design Cost Reduction Study. This report examines the future cost reductions that may accrue through the use of mass production, innovative manufacturing techniques, and new materials. Results are based on data collection and survey of optical component manufacturers, BDM experience, and existing cost models. These data provide a good representation of current methods and technologies from which future estimates can be made. From these data, a series of scaling relationships were developed to project future costs for a selected set of technologies. The scaling relationships are sensitive to cost driving parameters such as size and surface figure requirements as well as quantity requirements, production rate, materials, and manufacturing processes. In addition to the scaling relationships, descriptions of the selected processes were developed along with graphical representations of the processes. This report provides a useful tool in projecting the costs of advanced laser concepts at the component level of detail. A mix of the most diverse yet comparable technologies was chosen for this study. This yielded a useful, yet manageable number of variables to examine. The study has resulted in a first-order cost model which predicts the relative cost behavior of optical components within different variable constraints.

  10. Two laser-driven mix experiments to study reshock and shear

    NASA Astrophysics Data System (ADS)

    Welser-Sherrill, L.; Fincke, J.; Doss, F.; Loomis, E.; Flippo, K.; Offermann, D.; Keiter, P.; Haines, B.; Grinstein, F.

    2013-09-01

    In an effort to better understand mix in Inertial Confinement Fusion (ICF) implosion cores, a series of laser-driven mix experiments has been designed for the University of Rochester's OMEGA laser. Our objective is to perform experiments to investigate the turbulent mixing at material interfaces when subject to multiple shocks and reshocks or high-speed shear. Ultimately, these experiments are providing detailed quantitative measurements to assist in validation efforts for the BHR-2 mix model, which is implemented in the RAGE hydrodynamics code. The Reshock experiment studies the physical process of shocking and reshocking mix layers. Radiographs are recorded to compile a temporal evolution of the mixing layer and its subsequent reshock, compression, and re-growth phases. The Shear experiment investigates shear-driven growth of a mix layer, and radiography captures the time evolution of the development of turbulent mixing due to shear. Simulations of both the Reshock and Shear experiments using RAGE and the BHR-2 mix model demonstrate good agreement with the mix evolution seen in the experimental data, giving confidence that BHR-2 is capable of simulating the behavior of both compressive and shear-driven turbulent flows.