The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform

M. M. Marinak - One of the best experts on this subject based on the ideXlab platform.

  • national ignition facility targets driven at high radiation temperature ignition hydrodynamic stability and laser Plasma Interactions
    Physics of Plasmas, 2004
    Co-Authors: D E Hinkel, S. W. Haan, A. B. Langdon, C.h. Still, T R Dittrich, M. M. Marinak
    Abstract:

    A target design driven indirectly to ignition at a radiation temperature of 350 eV for the National Ignition Facility (NIF) is reported in integrated radiation-hydrodynamic simulations which detail the necessary specifications to achieve ignition and burn. The target is further analyzed to determine its hydrodynamic stability as well as its vulnerability to laser–Plasma Interactions. This target shows enhanced hydrodynamic stability over targets previously designed at lower radiation temperatures [S. W. Haan, S. M. Pollaine, J. D. Lindl et al., Phys. Plasmas 2, 2480 (1995); W. J. Krauser, N. M. Hoffman, D. C. Wilson et al., ibid.3, 2084 (1996); D. C. Wilson, P. A. Bradley, N. M. Hoffman et al., ibid.5, 1953 (1998); P. A. Bradley and D. C. Wilson, ibid.6, 4293 (1999)]. To control laser–Plasma instabilities, both polarization and temporal smoothing of the spatially smoothed NIF laser beams is necessary. Analyses of laser scatter in target blow-off at peak power demonstrate saturation in both the 300 and 350...

  • National Ignition Facility targets driven at high radiation temperature: Ignition, hydrodynamic stability, and laser–Plasma Interactions
    Physics of Plasmas, 2004
    Co-Authors: Denise Hinkel, S. W. Haan, A. B. Langdon, Tom Dittrich, C.h. Still, M. M. Marinak
    Abstract:

    A target design driven indirectly to ignition at a radiation temperature of 350 eV for the National Ignition Facility (NIF) is reported in integrated radiation-hydrodynamic simulations which detail the necessary specifications to achieve ignition and burn. The target is further analyzed to determine its hydrodynamic stability as well as its vulnerability to laser–Plasma Interactions. This target shows enhanced hydrodynamic stability over targets previously designed at lower radiation temperatures [S. W. Haan, S. M. Pollaine, J. D. Lindl et al., Phys. Plasmas 2, 2480 (1995); W. J. Krauser, N. M. Hoffman, D. C. Wilson et al., ibid.3, 2084 (1996); D. C. Wilson, P. A. Bradley, N. M. Hoffman et al., ibid.5, 1953 (1998); P. A. Bradley and D. C. Wilson, ibid.6, 4293 (1999)]. To control laser–Plasma instabilities, both polarization and temporal smoothing of the spatially smoothed NIF laser beams is necessary. Analyses of laser scatter in target blow-off at peak power demonstrate saturation in both the 300 and 350...

A. B. Langdon - One of the best experts on this subject based on the ideXlab platform.

  • Analyses of laser-Plasma Interactions in NIF ignition emulator designs
    Journal of Physics: Conference Series, 2010
    Co-Authors: Denise Hinkel, C.h. Still, L. J. Suter, D. A. Callahan, Nathan Meezan, David Strozzi, E. A. Williams, A. B. Langdon
    Abstract:

    The National Ignition Campaign is currently conducting energetics experiments at the National Ignition Facility (NIF). These experiments directly test all aspects of ignition hohlraum performance. An important aspect of good performance is understanding and mitigation of laser-Plasma Interactions, which enables laser coupling to the target. The hohlraum energetics target and pulse-shape are designed to produce an ignition-hohlraum-like Plasma to test laser-Plasma Interactions. The pre-shot laser-Plasma interaction predictions for the first energetics targets (one room temperature target, and one cryogenic target) are presented here. These findings correlate well with the experimental data, namely that the primary concern is stimulated Raman scatter of the inner beams deep in the target. Such scatter is mostly re-absorbed, but modifies the energy deposition profile and thus the symmetry. Stimulated Brillouin scatter is at low levels, both in pre-shot predictions and in the experiments.

  • Analyses of laser-Plasma Interactions in National Ignition Facility ignition targetsa)
    Physics of Plasmas, 2008
    Co-Authors: Denise Hinkel, A. B. Langdon, D. A. Callahan, Steven H. Langer, Charles H. Still, E. A. Williams
    Abstract:

    A capability to analyze laser-Plasma Interactions (LPI) for ignition targets to be fielded at the National Ignition Facility has been developed and exercised. LPI in these targets may cause direct energy loss (backscatter) or energy redirection (beam spray, deflection, and energy transfer). These analyses range from analyzing the gain exponents for backscatter and beam spray to performing massively parallel, three-dimensional simulations of laser beam propagation in the most promising candidate ignition target designs. In the former assessment, ignition designs are iterated to reduce the gain exponent values. In the latter, beam propagation simulations are performed to analyze the reflectivity and beam transmission of speckled laser beams in the computed Plasma profiles of the ignition targets. In current ignition designs, laser reflectivity is calculated to be well below 10%.

  • national ignition facility targets driven at high radiation temperature ignition hydrodynamic stability and laser Plasma Interactions
    Physics of Plasmas, 2004
    Co-Authors: D E Hinkel, S. W. Haan, A. B. Langdon, C.h. Still, T R Dittrich, M. M. Marinak
    Abstract:

    A target design driven indirectly to ignition at a radiation temperature of 350 eV for the National Ignition Facility (NIF) is reported in integrated radiation-hydrodynamic simulations which detail the necessary specifications to achieve ignition and burn. The target is further analyzed to determine its hydrodynamic stability as well as its vulnerability to laser–Plasma Interactions. This target shows enhanced hydrodynamic stability over targets previously designed at lower radiation temperatures [S. W. Haan, S. M. Pollaine, J. D. Lindl et al., Phys. Plasmas 2, 2480 (1995); W. J. Krauser, N. M. Hoffman, D. C. Wilson et al., ibid.3, 2084 (1996); D. C. Wilson, P. A. Bradley, N. M. Hoffman et al., ibid.5, 1953 (1998); P. A. Bradley and D. C. Wilson, ibid.6, 4293 (1999)]. To control laser–Plasma instabilities, both polarization and temporal smoothing of the spatially smoothed NIF laser beams is necessary. Analyses of laser scatter in target blow-off at peak power demonstrate saturation in both the 300 and 350...

  • National Ignition Facility targets driven at high radiation temperature: Ignition, hydrodynamic stability, and laser–Plasma Interactions
    Physics of Plasmas, 2004
    Co-Authors: Denise Hinkel, S. W. Haan, A. B. Langdon, Tom Dittrich, C.h. Still, M. M. Marinak
    Abstract:

    A target design driven indirectly to ignition at a radiation temperature of 350 eV for the National Ignition Facility (NIF) is reported in integrated radiation-hydrodynamic simulations which detail the necessary specifications to achieve ignition and burn. The target is further analyzed to determine its hydrodynamic stability as well as its vulnerability to laser–Plasma Interactions. This target shows enhanced hydrodynamic stability over targets previously designed at lower radiation temperatures [S. W. Haan, S. M. Pollaine, J. D. Lindl et al., Phys. Plasmas 2, 2480 (1995); W. J. Krauser, N. M. Hoffman, D. C. Wilson et al., ibid.3, 2084 (1996); D. C. Wilson, P. A. Bradley, N. M. Hoffman et al., ibid.5, 1953 (1998); P. A. Bradley and D. C. Wilson, ibid.6, 4293 (1999)]. To control laser–Plasma instabilities, both polarization and temporal smoothing of the spatially smoothed NIF laser beams is necessary. Analyses of laser scatter in target blow-off at peak power demonstrate saturation in both the 300 and 350...

  • An MPP hydrocode to study laser-Plasma Interactions
    1998
    Co-Authors: R. L. Berger, A. B. Langdon, C.h. Still, S H Langer, L. J. Suter, Williams E A
    Abstract:

    Because of the increased size and power inherent in a laser-AGEX on NIF, laser-Plasma Interactions (LPI) observed in NOVA AGEX play an increasingly important role. The process by which filamentation and stimulated backscatter grow is complex. Furthermore, there is a competition among the instabilities so that lessening one can increase another. Therefore, simulating them is an integral part to successful experiments on NIF. In this paper, we present a massively parallel hydrocode to simulate laser-Plasma Interactions in NIF-relevant AGEX regimes.

Denise Hinkel - One of the best experts on this subject based on the ideXlab platform.

  • Analyses of laser-Plasma Interactions in NIF ignition emulator designs
    Journal of Physics: Conference Series, 2010
    Co-Authors: Denise Hinkel, C.h. Still, L. J. Suter, D. A. Callahan, Nathan Meezan, David Strozzi, E. A. Williams, A. B. Langdon
    Abstract:

    The National Ignition Campaign is currently conducting energetics experiments at the National Ignition Facility (NIF). These experiments directly test all aspects of ignition hohlraum performance. An important aspect of good performance is understanding and mitigation of laser-Plasma Interactions, which enables laser coupling to the target. The hohlraum energetics target and pulse-shape are designed to produce an ignition-hohlraum-like Plasma to test laser-Plasma Interactions. The pre-shot laser-Plasma interaction predictions for the first energetics targets (one room temperature target, and one cryogenic target) are presented here. These findings correlate well with the experimental data, namely that the primary concern is stimulated Raman scatter of the inner beams deep in the target. Such scatter is mostly re-absorbed, but modifies the energy deposition profile and thus the symmetry. Stimulated Brillouin scatter is at low levels, both in pre-shot predictions and in the experiments.

  • Analyses of laser-Plasma Interactions in National Ignition Facility ignition targetsa)
    Physics of Plasmas, 2008
    Co-Authors: Denise Hinkel, A. B. Langdon, D. A. Callahan, Steven H. Langer, Charles H. Still, E. A. Williams
    Abstract:

    A capability to analyze laser-Plasma Interactions (LPI) for ignition targets to be fielded at the National Ignition Facility has been developed and exercised. LPI in these targets may cause direct energy loss (backscatter) or energy redirection (beam spray, deflection, and energy transfer). These analyses range from analyzing the gain exponents for backscatter and beam spray to performing massively parallel, three-dimensional simulations of laser beam propagation in the most promising candidate ignition target designs. In the former assessment, ignition designs are iterated to reduce the gain exponent values. In the latter, beam propagation simulations are performed to analyze the reflectivity and beam transmission of speckled laser beams in the computed Plasma profiles of the ignition targets. In current ignition designs, laser reflectivity is calculated to be well below 10%.

  • National Ignition Facility targets driven at high radiation temperature: Ignition, hydrodynamic stability, and laser–Plasma Interactions
    Physics of Plasmas, 2004
    Co-Authors: Denise Hinkel, S. W. Haan, A. B. Langdon, Tom Dittrich, C.h. Still, M. M. Marinak
    Abstract:

    A target design driven indirectly to ignition at a radiation temperature of 350 eV for the National Ignition Facility (NIF) is reported in integrated radiation-hydrodynamic simulations which detail the necessary specifications to achieve ignition and burn. The target is further analyzed to determine its hydrodynamic stability as well as its vulnerability to laser–Plasma Interactions. This target shows enhanced hydrodynamic stability over targets previously designed at lower radiation temperatures [S. W. Haan, S. M. Pollaine, J. D. Lindl et al., Phys. Plasmas 2, 2480 (1995); W. J. Krauser, N. M. Hoffman, D. C. Wilson et al., ibid.3, 2084 (1996); D. C. Wilson, P. A. Bradley, N. M. Hoffman et al., ibid.5, 1953 (1998); P. A. Bradley and D. C. Wilson, ibid.6, 4293 (1999)]. To control laser–Plasma instabilities, both polarization and temporal smoothing of the spatially smoothed NIF laser beams is necessary. Analyses of laser scatter in target blow-off at peak power demonstrate saturation in both the 300 and 350...

A. Fedotoff - One of the best experts on this subject based on the ideXlab platform.

  • Electron and photon production from relativistic laser–Plasma Interactions
    Nuclear Fusion, 2003
    Co-Authors: E. Lefebvre, N. Cochet, S. Fritzler, Victor Malka, M.-m. Aleonard, J.-f. Chemin, S. Darbon, L. Disdier, Jérôme Faure, A. Fedotoff
    Abstract:

    The interaction of short and intense laser pulses with Plasmas is a very efficient source of relativistic electrons with tunable properties. In low-density Plasmas, we observed bunches of electrons up to 200 MeV, accelerated in the wakefield of the laser pulse. Less energetic electrons (tens of megaelectronvolt) have been obtained, albeit with a higher efficiency, during the interaction with a pre-exploded foil or a solid target. When these relativistic electrons slow down in a thick tungsten target, they emit very energetic Bremsstrahlung photons which have been diagnosed directly with photoconductors, and indirectly through photonuclear activation measurements. Dose, photoactivation, and photofission measurements are reported. These results are in reasonable agreement, over three orders of magnitude, with a model built on laser–Plasma interaction and electron transport numerical simulations.

  • electron and photon production from relativistic laser Plasma Interactions
    Nuclear Fusion, 2003
    Co-Authors: E. Lefebvre, N. Cochet, S. Fritzler, Victor Malka, M.-m. Aleonard, J.-f. Chemin, S. Darbon, L. Disdier, Jérôme Faure, A. Fedotoff
    Abstract:

    The interaction of short and intense laser pulses with Plasmas is a very efficient source of relativistic electrons with tunable properties. In low-density Plasmas, we observed bunches of electrons up to 200 MeV, accelerated in the wakefield of the laser pulse. Less energetic electrons (tens of megaelectronvolt) have been obtained, albeit with a higher efficiency, during the interaction with a pre-exploded foil or a solid target. When these relativistic electrons slow down in a thick tungsten target, they emit very energetic Bremsstrahlung photons which have been diagnosed directly with photoconductors, and indirectly through photonuclear activation measurements. Dose, photoactivation, and photofission measurements are reported. These results are in reasonable agreement, over three orders of magnitude, with a model built on laser–Plasma interaction and electron transport numerical simulations.

D E Hinkel - One of the best experts on this subject based on the ideXlab platform.

  • multiple beam laser Plasma Interactions in inertial confinement fusiona
    Physics of Plasmas, 2014
    Co-Authors: J F Myatt, J Zhang, R W Short, A V Maximov, W Seka, D H Froula, D H Edgell, D T Michel, I V Igumenshchev, D E Hinkel
    Abstract:

    The experimental evidence for multiple-beam laser-Plasma instabilities of relevance to laser driven inertial confinement fusion at the ignition scale is reviewed, in both the indirect and direct-drive approaches. The instabilities described are cross-beam energy transfer (in both indirectly driven targets on the NIF and in direct-drive targets), multiple-beam stimulated Raman scattering (for indirect-drive), and multiple-beam two-plasmon decay instability (in direct drive). Advances in theoretical understanding and in the numerical modeling of these multiple beam instabilities are presented.

  • national ignition facility targets driven at high radiation temperature ignition hydrodynamic stability and laser Plasma Interactions
    Physics of Plasmas, 2004
    Co-Authors: D E Hinkel, S. W. Haan, A. B. Langdon, C.h. Still, T R Dittrich, M. M. Marinak
    Abstract:

    A target design driven indirectly to ignition at a radiation temperature of 350 eV for the National Ignition Facility (NIF) is reported in integrated radiation-hydrodynamic simulations which detail the necessary specifications to achieve ignition and burn. The target is further analyzed to determine its hydrodynamic stability as well as its vulnerability to laser–Plasma Interactions. This target shows enhanced hydrodynamic stability over targets previously designed at lower radiation temperatures [S. W. Haan, S. M. Pollaine, J. D. Lindl et al., Phys. Plasmas 2, 2480 (1995); W. J. Krauser, N. M. Hoffman, D. C. Wilson et al., ibid.3, 2084 (1996); D. C. Wilson, P. A. Bradley, N. M. Hoffman et al., ibid.5, 1953 (1998); P. A. Bradley and D. C. Wilson, ibid.6, 4293 (1999)]. To control laser–Plasma instabilities, both polarization and temporal smoothing of the spatially smoothed NIF laser beams is necessary. Analyses of laser scatter in target blow-off at peak power demonstrate saturation in both the 300 and 350...