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in creator/contributor: "Lasinski, B. F."

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Light Absorption and Scattering Mechanisms in Laser Fusion Plasmas

The picture of laser light absorption and scattering which is emerging from theory and computer simulation studies of laser-plasma interactions is described. On the subject of absorption, we discuss theoretical and experimental evidence that resonance absorption in a steepened density profile is a dominant absorption mechanism. Recent work also indicates the presence of critical surface ripples, which we study using two and three dimensional computer simulations. Predictions of hot electron spe… more

Date: October 4, 1977

Creator: Barnes, C.; Estabrook, K. G.; Kruer, W. L.; Langdon, A. B.; Lasinski, B. F.; Max, C. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

ARGUS laser plasma experiments at 1. 06. mu. m, 0. 53. mu. m and 0. 35. mu. m

ARGUS wavelength scaling experiments have been performed on low (Be) and high (Au) Z disk targets, with laser wavelengths of 1.06 ..mu..m, 0.53 ..mu..m and 0.35 ..mu..m. The laser provided a 700 psec pulse, with up to 100J and 1.06 ..mu..m; 200J at 0.53 ..mu..m; and 40J at 0.35 ..mu..m. Laser intensities on target ranged from 3 x 10/sup 13/ to over 3 x 10/sup 15/W/cm/sup 2/, using an f/2.2 focusing system. Box calorimeter measurements show the expected increasing fractional absorption at shorte… more

Date: January 1, 1982

Creator: Turner, R. E.; Campbell, E. M.; Mead, W. C.; Ze, F.; Max, C.; Phillion, D. W. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

On Point Designs for High Gain Fast Ignition

Fast ignition research has reached the stage where point designs are becoming crucial to the identification of key issues and the development of projects to demonstrate high gain fast ignition. The status of point designs for cone coupled electron fast ignition and some of the issues they highlight are discussed.

Date: September 27, 2007

Creator: Key, M.; Akli, K.; Beg, F.; Betti, R.; Clark, D. S.; Chen, S. N. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Materials Science at the Extremes of Pressure and Strain Rate

Solid state experiments at very high pressures and strain rates are possible on high power laser facilities, albeit over brief intervals of time and spatial small scales. A new shockless drive has been developed on the Omega laser. VISAR measurements establish the high strain rates, 10{sup 7}-10{sup 8} s{sup -1}. Solid-state strength is inferred using the Rayleigh-Taylor instability as a ''diagnostic''. Temperature and compression in polycrystalline samples can be deduced from EXAFS measurement… more

Date: August 20, 2003

Creator: Remington, B. A.; Cavallo, R. M.; Edwards, M. J.; Lasinski, B. F.; Lorenz, K. T.; Lorenzana, H. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Optical scatterng measurements from 1. 06. mu. m, and 0. 35. mu. m laser heated targets

Scattered light measurements have been obtained on Argus disk target experiments at 1.06 ..mu..m, 0.53 ..mu..m, and 0.35 ..mu..m laser wavelengths. We present backscatter measurements taken near the three laser wavelengths for SBS, and measurements of the three-halves and second harmonics taken during the two longer wavelength laser irradiations. The SBS measurements show the strong influence of the increased absorption at the shorter laser wavelengths. The spectra of the three-halves harmonic … more

Date: October 1, 1981

Creator: Turner, R. E.; Cambpell, E. M.; Hermes, G.; Lasinski, B. F.; Mead, W. L.; Phillion, D. W. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Scaling of laser-plasma interactions with laser wavelength and plasma size

Plasma size is an important parameter in wavelength-scaling experiments because it determines both the threshold and potential gain for a variety of laser-plasma instabilities. Most experiments to date have of necessity produced relatively small plasmas, due to laser energy and pulse-length limitations. We have discussed in detail three recent Livermore experiments which had large enough plasmas that some instability thresholds were exceeded or approached. Our evidence for Raman scatter, filame… more

Date: January 25, 1983

Creator: Max, C. E.; Campbell, E. M.; Mead, W. C.; Kruer, W. L.; Phillion, D. W.; Turner, R. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Free-electron laser experiments in the microwave tokamak experiment

Microwave pulses have been injected from a free electron-laser (FEL) into the Microwave Tokamak Experiment (MTX) at up to 0.2 GW at 140 GHz in short pulses (10-ns duration) with O-mode polarization. The power transmitted through the plasma was measured in a first experimental study of high power pulse propagation in the plasma; no nonlinear effects were found at this power level. Calculations indicate that nonlinear effects may be found at the higher power densities expected in future experimen… more

Date: August 1, 1990

Creator: Allen, S. L.; Brown, M. D.; Byers, J. A.; Casper, T. A.; Cohen, B. I.; Cohen, R. H. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A Reduced Model of Kinetic Effects Related to the Saturation of Stimulated Brillouin Scattering

We developed a reduced description of kinetic effects that is included in a fluid model of stimulated Brillouin backscattering (SBS) in low Z plasmas (e.g. He, Be). Following hybrid-PIC simulations, the modified ion distribution function is parametrized by the width {delta} of the plateau created by trapping around the phase velocity of the SBS-driven acoustic wave. An evolution equation is derived for {delta}, which affects SBS through a frequency shift and a reduced Landau damping. This model… more

Date: August 26, 2003

Creator: Divol, L.; Williams, E. A.; Cohen, B. I.; Langdon, A. B. & Lasinski, B. F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Accessing High Pressure States Relevant to Core Conditions in the Giant Planets

We have designed an experimental technique to use on the National Ignition Facility (NIF) laser to achieve very high pressure (P{sub max} > 10 Mbar = 1000 GPa), dense states of matter at moderate temperatures (kT < 0.5 eV = 6000 K), relevant to the core conditions of the giant planets. A discussion of the conditions in the interiors of the giant planets is given, and an experimental design that can approach those conditions is described.

Date: April 15, 2004

Creator: Remington, B. A.; Cavallo, R. M.; Edwards, M. J.; Ho, D. D.; Lorenz, K. T.; Lorenzana, H. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

LSP Calculations of Cone-Wire Experiments

Recent experiments at the Institute of Laser Engineering (ILE) in Japan [1] and at Rutherford Appleton Laboratory (RAL) in the United Kingdom [2] have shown good coupling of short-pulse high-intensity laser light into high-energy electrons channeled down a narrow fiber. Such target configurations are being considered as backlighter targets on the National Ignition Facility (NIF). We will report on LSP calculations of these cone-wire experiments and other candidate target configurations. These c… more

Date: June 13, 2005

Creator: Town, R. J.; Cottrill, L. A.; Key, M. H.; Kruer, W. L.; Langdon, A. B.; Lasinski, B. F. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Gigagauss Magnetic Field Generation From High Intensity Laser Solid Interactions

Intense laser (>10<sup>21</sup> W/cm2 ) sources using pulse compression techniques in the sub-picosecond time frame have been used to create dynamic electric field strenghs in excess of 100 Megavolts/micron with associated magnetic field strengths in the Gigagauss regime. We have begun a series of experiments using the Petawatt Laser system at LLNL to determine the potential of these sources for a variety of applications. Hot electron spectra from laser-target interactions in Au have been measu… more

Date: October 15, 1998

Creator: Cowan, T.; Moran, M.; Hammer, J.; Hatchett, S.; Hunt, A.; Key, M. H. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The Potential of Fast Ignition and Related Experiments With a Petawatt Laser Facility

A model of energy gain induced by fast ignition of thermonuclear burn in compressed deuterium-tritium fuel, is used to show the potential for 300x gain with a driver energy of 1 M J, if the National Ignition Facility (NIF) were to be adapted for fast ignition. The physics of fast ignition has been studied using a petawatt laser facility at the Lawrence Livermore National Laboratory. Laser plasma interaction in a preformed plasma on a solid target leads to relativistic self-focusing evidenced by… more

Date: April 6, 2000

Creator: Key, M. H.; Campbell, E. M.; Cowan, T. E.; Hatchett, S. P.; Henry, E. A.; Koch, J. A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Progress in Fast Ignitor Research With the Nova Petawatt Laser Facility

The physics of fast ignition is being studied using a petawatt laser facility at the Lawrence Livermore National Laboratory. Performance of the PW laser with deformable mirror wavefront control giving intensities up to 3x10{sup 20} Wcm{sup {minus}2} is described. Measurements of the efficiency of conversion of laser energy to relativistic electrons and of their energy spectrum and angular distribution including an observed narrow beam angle of {+-}15{degree}, are reported. Heating by the electr… more

Date: November 10, 1998

Creator: Cowan, T. E.; Hammel, B. A.; Hatchett, S. P.; Henry, E. A.; Key, M. H.; Kilkenny, J. D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

ARGUS disk-target experiments at 1. 06. mu. m, 0. 53. mu. m, 0. 35. mu. m

We report on ARGUS wavelength scaling experiments on disk targets at 1.06 ..mu..m, 0.53 ..mu..m, and 0.35 ..mu..m. Measurements were made of absorption, stimulated Brillouin and Raman scattering, and 3/2 harmonic light.

Date: January 1, 1982

Creator: Turner, R. E.; Campbell, E. M.; Mead, W. C.; Ze, F.; Max, C.; Phillion, D. W. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Materials Science under Extreme Conditions of Pressure and Strain Rate

Solid state dynamics experiments at very high pressures (P >> 10 GPa) and strain rates ({var_epsilon} >> 10{sup 5} s{sup -1}) have been demonstrated on high energy laser facilities, albeit over brief intervals of time and small spatial scales. We have developed two methods for driving samples to high pressures (10-100 GPa) at high strain rate (10{sup 6}-10{sup 8} s{sup -1}) in the solid state. One method uses a shockless compression technique, and the other uses multiple staged shoc… more

Date: March 27, 2003

Creator: Remington, B. A.; Bazan, G.; Bringa, E.; Caturla, M.; Edwards, M. J.; Glendinning, S. G. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Raman Generated Magnetic Fields in Laser Light Speckles

In modern 2D and 3D PIC simulations relevant to National Ignition Facility (NIF) parameters, the low frequency magnetic fields associated with the localized fast electron currents generated by Stimulated Raman Scatter have been identified. We consider electron plasma densities from 0.1 to 0.2 of critical density (n{sub c}) and electron plasma temperatures (T{sub e}) from a few keV to over 10 keV in simulations with space scales corresponding to a laser speckle in modeling with our massively par… more

Date: September 2, 2003

Creator: Lasinski, B. F.; Still, C. H.; Langdon, A. B.; Hinkel, D. E. & Williams, E. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Simulations Of Electron Transport For Fast Ignition Using LSP

A crucial issue for the viability of the fast ignition approach to inertial fusion energy is the transport of the ignition pulse energy from the critical surface to the high-density compressed fuel. Experiments have characterized this transport through the interaction of short pulse, high intensity lasers with solid-density targets containing thin K{sub alpha} fluorescence layers. These experiments show a reasonably well-collimated beam, although with a significantly larger radius than the inci… more

Date: May 27, 2004

Creator: Town, R. J.; Chen, C.; Cottrill, L. A.; Key, M. H.; Kruer, W. L.; Langdon, A. B. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Computational Methods for Collisional Plasma Physics

Modeling the high density, high temperature plasmas produced by intense laser or particle beams requires accurate simulation of a large range of plasma collisionality. Current simulation algorithms accurately and efficiently model collisionless and collision-dominated plasmas. The important parameter regime between these extremes, semi-collisional plasmas, has been inadequately addressed to date. LLNL efforts to understand and harness high energy-density physics phenomena for stockpile stewards… more

Date: February 18, 2004

Creator: Lasinski, B. F.; Larson, D. J.; Hewett, D. W.; Langdon, A. B. & Still, C. H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Laser-Plasma Interactions in Drive Campaign targets on the National Ignition Facility

No Description Available.

Date: November 16, 2013

Creator: Hinkel, D. E.; Callahan, D. A.; Moody, J. D.; Amendt, P. A.; Lasinski, B. F.; MacGowan, B. J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Progress Toward Ignition at the National Ignition Facility

No Description Available.

Date: July 3, 2013

Creator: Hinkel, D. E.; Edwards, M. J.; Amendt, P. A.; Benedetti, R.; Hopkins, L. B.; Bleuel, D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Development and Application of a Predictive Computational Tool for Short-Pulse, High-Intensity Target Interactions

The widely differing spatial, temporal, and density scales needed to accurately model the fast ignition process and other short-pulse laser-plasma interactions leads to a computationally challenging project that is difficult to solve using a single code. This report summarizes the work performed on a three year LDRD to couple together three independent codes using PYTHON to build a new integrated computational tool. An example calculation using this new model is described.

Date: January 26, 2007

Creator: Town, R. J.; Chung, H.; Langdon, A. B.; Lasinski, B. F.; Lund, S. M.; McCandless, B. C. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Exploring the Fast Ignition Approach to Fusion Energy

Probably the most famous equation in physics is Einstein's E=mc{sup 2}, which was contained within his fifth and final paper that was published in 1905. It is this relationship between energy ( E) and mass ( m) that the fusion process exploits to generate energy. When two isotopes of hydrogen (normally Deuterium and Tritium (DT)) fuse they form helium and a neutron. In this process some of the mass of the hydrogen is converted into energy. In the fast ignition approach to fusion a large driver … more

Date: April 18, 2005

Creator: Town, R. J.; Chung, H.; Cottrill, L. A.; Foord, M.; Hatchett, S. P.; Key, M. H. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Effect of Shock Proximity on Richtmyer-Meshkov Growth

We report here experiments, conducted on the Omega laser [T.R. Boehly et al., Optics Commun. 133, 495 (1997)], and simulations that show reduced Richtmyer-Meshkov growth rates in a strongly shocked system with linear initial amplitudes (k{eta}{sub 0} {le} 0.9). The growth rate at early time is less than half the impulsive model prediction, rising at later time to near the impulsive prediction. An analytical model that accounts for shock proximity agrees with the results.

Date: October 31, 2002

Creator: Glendinning, S. G.; Bolstad, J.; Braun, D. G.; Edwards, M. J.; Hsing, W. W.; Lasinski, B. F. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

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

In our Petawatt laser experiments several hundred joules of 1 {micro}m laser light in 0.5-5.0 ps pulses with intensities up to 3 x 10{sup 20}Wcm{sup -2} were incident on solid targets producing a strongly relativistic interaction. The energy content, spectra, and angular patterns of the photon, electron, and ion radiations were diagnosed in a number of ways, including several novel (to laser physics) nuclear activation techniques. From the beamed bremsstrahlung we infer that about 40-50% of the… more

Date: November 12, 1999

Creator: Hatchett, S. P.; Brown, C. G.; Cowan, T. E.; Henry, E. A.; Johnson, J.; Key, M. H. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department