skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Flash Kα radiography of laser-driven solid sphere compression for fast ignition

Abstract

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/cm{sup 2}. The temporal evolution of the experimental and simulated areal densities with a 2-D radiation-hydrodynamics code is in good agreement.

Authors:
 [1]; ; ; ; ; ; ;  [2]; ;  [3];  [4];  [5];  [6];  [7];  [8]
  1. Department of Physics, University of Nevada Reno, Reno, Nevada 89557 (United States)
  2. Institute of Laser Engineering, Osaka University, Suita, Osaka (Japan)
  3. Department of Aerospace Engineering, Tohoku University, Sendai, Miyagi (Japan)
  4. Institute of Laser Technology, Nishi-ku, Osaka (Japan)
  5. University of California San Diego, La Jolla, California 92093 (United States)
  6. Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)
  7. LULI, Ecole Polytechnique, Palaiseau, Cedex (France)
  8. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
Publication Date:
OSTI Identifier:
22590833
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 108; Journal Issue: 25; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPRESSION; DENSITY; LASERS; MAGNESIUM 26; SPHERICAL CONFIGURATION; THERMONUCLEAR IGNITION; TWO-DIMENSIONAL SYSTEMS; X RADIATION; X-RAY RADIOGRAPHY

Citation Formats

Sawada, H., Lee, S., Nagatomo, H., Arikawa, Y., Nishimura, H., Ueda, T., Shigemori, K., Fujioka, S., Shiroto, T., Ohnishi, N., Sunahara, A., Beg, F. N., Theobald, W., Pérez, F., and Patel, P. K. Flash Kα radiography of laser-driven solid sphere compression for fast ignition. United States: N. p., 2016. Web. doi:10.1063/1.4954383.
Sawada, H., Lee, S., Nagatomo, H., Arikawa, Y., Nishimura, H., Ueda, T., Shigemori, K., Fujioka, S., Shiroto, T., Ohnishi, N., Sunahara, A., Beg, F. N., Theobald, W., Pérez, F., & Patel, P. K. Flash Kα radiography of laser-driven solid sphere compression for fast ignition. United States. doi:10.1063/1.4954383.
Sawada, H., Lee, S., Nagatomo, H., Arikawa, Y., Nishimura, H., Ueda, T., Shigemori, K., Fujioka, S., Shiroto, T., Ohnishi, N., Sunahara, A., Beg, F. N., Theobald, W., Pérez, F., and Patel, P. K. 2016. "Flash Kα radiography of laser-driven solid sphere compression for fast ignition". United States. doi:10.1063/1.4954383.
@article{osti_22590833,
title = {Flash Kα radiography of laser-driven solid sphere compression for fast ignition},
author = {Sawada, H. and Lee, S. and Nagatomo, H. and Arikawa, Y. and Nishimura, H. and Ueda, T. and Shigemori, K. and Fujioka, S. and Shiroto, T. and Ohnishi, N. and Sunahara, A. and Beg, F. N. and Theobald, W. and Pérez, F. and Patel, P. K.},
abstractNote = {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/cm{sup 2}. The temporal evolution of the experimental and simulated areal densities with a 2-D radiation-hydrodynamics code is in good agreement.},
doi = {10.1063/1.4954383},
journal = {Applied Physics Letters},
number = 25,
volume = 108,
place = {United States},
year = 2016,
month = 6
}
  • The HYDRA radiation-hydrodynamics code [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] is used to explore one-sided axial target illumination with annular and solid-profile uranium ion beams at 60 GeV to compress and ignite deuterium-tritium fuel filling the volume of metal cases with cross sections in the shape of an ''X'' (X-target). Quasi-three-dimensional, spherical fuel compression of the fuel toward the X-vertex on axis is obtained by controlling the geometry of the case, the timing, power, and radii of three annuli of ion beams for compression, and the hydroeffects of those beams heating the case as well asmore » the fuel. Scaling projections suggest that this target may be capable of assembling large fuel masses resulting in high fusion yields at modest drive energies. Initial two-dimensional calculations have achieved fuel compression ratios of up to 150X solid density, with an areal density {rho}R of about 1 g/cm{sup 2}. At these currently modest fuel densities, fast ignition pulses of 3 MJ, 60 GeV, 50 ps, and radius of 300 {mu}m are injected through a hole in the X-case on axis to further heat the fuel to propagating burn conditions. The resulting burn waves are observed to propagate throughout the tamped fuel mass, with fusion yields of about 300 MJ. Tamping is found to be important, but radiation drive to be unimportant, to the fuel compression. Rayleigh-Taylor instability mix is found to have a minor impact on ignition and subsequent fuel burn-up.« less
  • In order to investigate the intense laser propagation and channel formation in dense plasma, we conducted an experiment with proton deflectometry on the OMEGA EP Laser facility. The proton image was analyzed by tracing the trajectory of mono-energetic protons, which provides understanding the electric and magnetic fields that were generated around the channel. The estimated field strengths (E ∼ 10{sup 11} V/m and B ∼ 10{sup 8} G) agree with the predictions from 2D-Particle-in-cell (PIC) simulations, indicating the feasibility of the proton deflectometry technique for over-critical density plasma.
  • We dynamically compress solid deuterium over <100 ps from initial pressures of 22 GPa to 55 GPa, to final pressures as high as 71 GPa, with <40 μJ of pulse energy. At 25 GPa initial pressure, we measure compression wave speeds consistent with quasi-isentropic compression and a 24% increase in density. The laser drive energy per unit density change is 109 times smaller than it is for recent longer (~30 ns) time scale compression experiments. This suggests that, for a given final density, dynamic compression of hydrogen might be achieved using orders of magnitude lower laser energy than currently used.