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Title: Simultaneous diagnosis of radial profiles and mix in NIF ignition-scale implosions via X-ray spectroscopy

Journal Article · · Physics of Plasmas
DOI: https://doi.org/10.1063/1.5000774 · OSTI ID:1438689
 [1];  [2];  [3];  [2]; ORCiD logo [4];  [1];  [4];  [1]; ORCiD logo [3];  [1]
  1. Univ. of Oxford (United Kingdom). Dept. of Physics. Clarendon Lab.
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Univ. of York (United Kingdom). Dept. of Physics
  4. Univ. of Rochester, NY (United States). Lab. for Laser Energetics
+ Show Author Affiliations

In a National Ignition Facility implosion, hydrodynamic instabilities may cause the cold material from the imploding shell to be injected into the hot-spot (hot-spot mix), enhancing the radiative and conductive losses, which in turn may lead to a quenching of the ignition process. The bound-bound features of the spectrum emitted by high-Z ablator dopants that get mixed into the hot-spot have been previously used to infer the total amount of mixed mass; however, the typical errorbars are larger than the maximum tolerable mix. We present in this paper an improved 2D model for mix spectroscopy which can be used to retrieve information on both the amount of mixed mass and the full imploded plasma profile. By performing radiation transfer and simultaneously fitting all of the features exhibited by the spectra, we are able to constrain self-consistently the effect of the opacity of the external layers of the target on the emission, thus improving the accuracy of the inferred mixed mass. The model's predictive capabilities are first validated by fitting simulated spectra arising from fully characterized hydrodynamic simulations, and then, the model is applied to previously published experimental results, providing values of mix mass in agreement with previous estimates. Finally, we show that the new self consistent procedure leads to better constrained estimates of mix and also provides insight into the sensitivity of the hot-spot spectroscopy to the spatial properties of the imploded capsule, such as the in-flight aspect ratio of the cold fuel surrounding the hotspot.

Research Organization:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Univ. of Rochester, NY (United States); Univ. of Oxford (United Kingdom); University of York (United Kingdom)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA); New York State Energy Research and Development Authority (NYSERDA) (United States); Engineering and Physical Sciences Research Council (EPSRC); Royal Society (United Kingdom)
Grant/Contract Number:
AC52-07NA27344; NA0001944; EP/L000849/1; EP/L000644/1; EP/H035877/1
OSTI ID:
1438689
Alternate ID(s):
OSTI ID: 1407434
Report Number(s):
LLNL-JRNL-736521; TRN: US1900487
Journal Information:
Physics of Plasmas, Vol. 24, Issue 11; ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English

References (21)

Special Topic: Plans for the National Ignition Campaign (NIC) on the National Ignition Facility (NIF): On the threshold of initiating ignition experiments journal May 2011
Hot-Spot Mix in Ignition-Scale Inertial Confinement Fusion Targets journal July 2013
Pressure ionization in laser-fusion target simulation journal May 1980
Measurement of Hydrodynamic Growth near Peak Velocity in an Inertial Confinement Fusion Capsule Implosion using a Self-Radiography Technique journal July 2016
GLF - A simulation code for X-ray lasers journal January 1994
High-mode Rayleigh-Taylor growth in NIF ignition capsules journal June 2010
Lowering of Ionization Potentials in Plasmas journal April 1966
Onset of Hydrodynamic Mix in High-Velocity, Highly Compressed Inertial Confinement Fusion Implosions journal August 2013
Cryogenic thermonuclear fuel implosions on the National Ignition Facility journal May 2012
Hot-spot mix in ignition-scale implosions on the NIF journal May 2012
Detailed model for hot-dense aluminum plasmas generated by an x-ray free electron laser journal February 2016
Point design targets, specifications, and requirements for the 2010 ignition campaign on the National Ignition Facility journal May 2011
The physics basis for ignition using indirect-drive targets on the National Ignition Facility journal February 2004
South pole bang-time diagnostic on the National Ignition Facility (invited) journal October 2012
Lowering of the Ionization Energy for a Plasma in Thermodynamic Equilibrium journal January 1963
Cretin—a radiative transfer capability for laboratory plasmas journal October 2001
Hydrodynamics and K-shell radiation emission of laser compressed Ar-filled glass microballoons journal July 1988
Measurements of continuum lowering in solid-density plasmas created from elements and compounds journal May 2016
A comparison of three-dimensional multimode hydrodynamic instability growth on various National Ignition Facility capsule designs with HYDRA simulations journal April 1998
X-ray Spectroscopy of Laser Imploded Targets
  • Yaakobi, B.; Skupsky, S.; McCrory, R. L.
  • Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 300, Issue 1456 https://doi.org/10.1098/rsta.1981.0090
journal April 1981
Direct Measurements of the Ionization Potential Depression in a Dense Plasma journal August 2012

Cited By (4)

Fluorescence and absorption spectroscopy for warm dense matter studies and ICF plasma diagnostics journal May 2018
Deep learning: A guide for practitioners in the physical sciences journal August 2018
X-ray spectroscopy of planar laser-plasma interaction experiments at the National Ignition Facility journal January 2019
Interpreting the electron temperature inferred from x-ray continuum emission for direct-drive inertial confinement fusion implosions on OMEGA journal August 2019

Figures / Tables (8)

FIG. 1(p. 4)figure FIG. 1
FIG. 2(p. 5)figure FIG. 2
FIG. 3(p. 6)figure FIG. 3
FIG. 4(p. 6)figure FIG. 4
FIG. 5(p. 7)figure FIG. 5
FIG. 6(p. 7)figure FIG. 6
Fig. 7(p. 9)figure Fig. 7
TABLE I(p. 10)table TABLE I

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