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Title: Role of hydrodynamics simulations in laser-plasma interaction predictive capability

Abstract

Efforts to predict and control laser-plasma interactions (LPI) in ignition hohlraum targets for the National Ignition Facility [G. H. Miller et al., Opt. Eng. 43, 2841 (2004)] are based on plasma conditions provided by radiation hydrodynamic simulations. Recent experiments provide compelling evidence that codes such as HYDRA [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] can accurately predict the plasma conditions in laser-heated targets such as gas-filled balloon (gasbag) and hohlraum platforms for studying LPI. Initially puzzling experimental observations are found to be caused by bulk hydrodynamic phenomena. Features in backscatter spectra and transmitted light spectra are reproduced from the simulated plasma conditions. Simulations also agree well with Thomson scattering measurements of the electron temperature. The calculated plasma conditions are used to explore a linear-gain based phenomenological model of backscatter. For long plasmas at ignition-relevant electron temperatures, the measured backscatter increases monotonically with gain and is consistent with linear growth for low reflectivities. These results suggest a role for linear gain postprocessing as a metric for assessing LPI risk.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;  [1]
  1. Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States)
Publication Date:
OSTI Identifier:
20975062
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2710782; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CONTROL; ELECTRON TEMPERATURE; GAIN; HYDRODYNAMICS; ION TEMPERATURE; LASERS; PLASMA; PLASMA DIAGNOSTICS; PLASMA HEATING; PLASMA SIMULATION; THOMSON SCATTERING; US NATIONAL IGNITION FACILITY

Citation Formats

Meezan, N. B., Berger, R. L., Divol, L., Froula, D. H., Hinkel, D. E., Jones, O. S., London, R. A., Moody, J. D., Marinak, M. M., Niemann, C., Neumayer, P. B., Prisbrey, S. T., Ross, J. S., Williams, E. A., Glenzer, S. H., and Suter, L. J. Role of hydrodynamics simulations in laser-plasma interaction predictive capability. United States: N. p., 2007. Web. doi:10.1063/1.2710782.
Meezan, N. B., Berger, R. L., Divol, L., Froula, D. H., Hinkel, D. E., Jones, O. S., London, R. A., Moody, J. D., Marinak, M. M., Niemann, C., Neumayer, P. B., Prisbrey, S. T., Ross, J. S., Williams, E. A., Glenzer, S. H., & Suter, L. J. Role of hydrodynamics simulations in laser-plasma interaction predictive capability. United States. doi:10.1063/1.2710782.
Meezan, N. B., Berger, R. L., Divol, L., Froula, D. H., Hinkel, D. E., Jones, O. S., London, R. A., Moody, J. D., Marinak, M. M., Niemann, C., Neumayer, P. B., Prisbrey, S. T., Ross, J. S., Williams, E. A., Glenzer, S. H., and Suter, L. J. Tue . "Role of hydrodynamics simulations in laser-plasma interaction predictive capability". United States. doi:10.1063/1.2710782.
@article{osti_20975062,
title = {Role of hydrodynamics simulations in laser-plasma interaction predictive capability},
author = {Meezan, N. B. and Berger, R. L. and Divol, L. and Froula, D. H. and Hinkel, D. E. and Jones, O. S. and London, R. A. and Moody, J. D. and Marinak, M. M. and Niemann, C. and Neumayer, P. B. and Prisbrey, S. T. and Ross, J. S. and Williams, E. A. and Glenzer, S. H. and Suter, L. J.},
abstractNote = {Efforts to predict and control laser-plasma interactions (LPI) in ignition hohlraum targets for the National Ignition Facility [G. H. Miller et al., Opt. Eng. 43, 2841 (2004)] are based on plasma conditions provided by radiation hydrodynamic simulations. Recent experiments provide compelling evidence that codes such as HYDRA [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] can accurately predict the plasma conditions in laser-heated targets such as gas-filled balloon (gasbag) and hohlraum platforms for studying LPI. Initially puzzling experimental observations are found to be caused by bulk hydrodynamic phenomena. Features in backscatter spectra and transmitted light spectra are reproduced from the simulated plasma conditions. Simulations also agree well with Thomson scattering measurements of the electron temperature. The calculated plasma conditions are used to explore a linear-gain based phenomenological model of backscatter. For long plasmas at ignition-relevant electron temperatures, the measured backscatter increases monotonically with gain and is consistent with linear growth for low reflectivities. These results suggest a role for linear gain postprocessing as a metric for assessing LPI risk.},
doi = {10.1063/1.2710782},
journal = {Physics of Plasmas},
number = 5,
volume = 14,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • Efforts to predict and control laser-plasma interactions (LPI) in ignition hohlraum targets for the National Ignition Facility [G. H. Miller et al., Optical Eng. 43, 2841 (2004)] are based on plasma conditions provided by radiation hydrodynamic simulations. Recent experiments provide compelling evidence that codes such as hydra [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] can accurately predict the plasma conditions in laser heated targets such as gas-filled balloon (gasbag) and hohlraum platforms for studying LPI. Initially puzzling experimental observations are found to be caused by bulk hydrodynamic phenomena. Features in backscatter spectra and transmitted light spectra aremore » reproduced from the simulated plasma conditions. Simulations also agree well with Thomson scattering measurements of the electron temperature. The calculated plasma conditions are used to explore a linear-gain based phenomenological model of backscatter. For long plasmas at ignition-relevant electron temperatures, the measured backscatter increases monotonically with gain and is consistent with linear growth for low reflectivities. These results suggest a role for linear gain postprocessing as a metric for assessing LPI risk.« less
  • We have developed a new target platform to study Laser Plasma Interaction in ignition-relevant condition at the Omega laser facility (LLE/Rochester)[1]. By shooting an interaction beam along the axis of a gas-filled hohlraum heated by up to 17 kJ of heater beam energy, we were able to create a millimeter-scale underdense uniform plasma at electron temperatures above 3 keV. Extensive Thomson scattering measurements allowed us to benchmark our hydrodynamic simulations performed with HYDRA[2]. As a result of this effort, we can use with much confidence these simulations as input parameters for our LPI simulation code pF3d[3]. In this paper, wemore » show that by using accurate hydrodynamic profiles and full three-dimensional simulations including a realistic modeling of the laser intensity pattern generated by various smoothing options, whole beam three-dimensional linear kinetic modeling of stimulated Brillouin scattering reproduces quantitatively the experimental measurements(SBS thresholds, reflectivity values and the absence of measurable SRS). This good agreement was made possible by the recent increase in computing power routinely available for such simulations. These simulations accurately predicted the strong reduction of SBS measured when polarization smoothing is used.« less
  • New experimental capabilities [Froula et al., Phys. Rev. Lett. 98, 085001 (2007)] have been developed to study laser-plasma interaction (LPI) in ignition-relevant condition at the Omega laser facility (LLE/Rochester). By shooting an interaction beam along the axis of a gas-filled hohlraum heated by up to 17 kJ of heater beam energy, a millimeter-scale underdense uniform plasma at electron temperatures above 3 keV was created. Extensive Thomson scattering measurements allowed to benchmark hydrodynamic simulations performed with HYDRA [Meezan et al., Phys. Plasmas 14, 056304 (2007)]. As a result of this effort, these simulations can be used with much confidence as inputmore » parameters for the LPI simulation code PF3D [Berger et al., Phys. Plasmas 5, 4337 (1998)]. In this paper, it is shown that by using accurate hydrodynamic profiles and full three-dimensional simulations including a realistic modeling of the laser intensity pattern generated by various smoothing options, whole beam three-dimensional linear kinetic modeling of stimulated Brillouin scattering (SBS) reproduces quantitatively the experimental measurements (SBS thresholds, reflectivity values, and the absence of measurable stimulated Raman scattering). This good agreement was made possible by the recent increase in computing power routinely available for such simulations. These simulations accurately predicted the strong reduction of SBS measured when polarization smoothing is used.« less
  • The interaction between two neighboring laser beams focused in a hot underdense homogeneous plasma is investigated using the non-paraxial wave coupling code KOLIBRI [S. H{umlt u}ller {ital et al.}, Phys. Scr. {bold T63}, 151 (1996)] in two and three spatial dimensions. Both the plasma hydrodynamic evolution and the stimulated Brillouin scattering (SBS) aspects are studied in the case of strongly damped ion sound waves. The hydrodynamic effects consist in ponderomotively driven density perturbations located between the beams which may, in turn, influence strongly the light propagation through the plasma. The two beams are found to merge whenever the distance betweenmore » them is smaller than or of the order of their diameter. Concerning the SBS aspect, it is found that due to interference effects between the beams, the spatial amplification of the backscattered light is asymmetric with respect to the laser axis. SBS can also enforce the hydrodynamic effects and the beam merging. {copyright} {ital 1997 American Institute of Physics.}« less
  • Understanding the behavior of a plasma chamber component in the fusion environment requires a simulation technique that is capable of integrating multi-disciplinary computational codes while appropriately treating geometric heterogeneity and complexity. Such a tool should be able to interpret phenomena from mutually dependent scientific disciplines and predict performance with sufficient accuracy and consistency. Integrated multi-physics simulation predictive capability (ISPC) relies upon advanced numerical simulation techniques and is being applied to ITER first wall/shield and Test Blanket Module (TBM) designs. In this paper, progress in ISPC development is described through the presentation of a number of integrated simulations. The simulations covermore » key physical phenomena encountered in a fusion plasma chamber system, including tritium permeation, fluid dynamics, and structure mechanics. Interface engines were developed in order to pass field data, such as surface deformation or nuclear heating rate, from the structural analysis to the thermo-fluid MHD analysis code for magnetohydrodynamic (MHD) velocity profile assessments, or from the neutronics analysis to the thermo-fluid analysis for temperature calculations, respectively. Near-term effort toward further ISPC development is discussed.« less