Precision Shock Tuning on the National Ignition Facility
Name
Robey-2012-Precision Shock Tuning on the National Ignition Facility.pdf
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Author(s)
Frenje, Johan A.
Casey, Daniel Thomas
Gatu Johnson, Maria
Seguin, Fredrick Hampton
Date Issued
May 2012
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Robey, H. et al. “Precision Shock Tuning on the National Ignition Facility.” Physical Review Letters 108.21 (2012). © 2012 American Physical Society
Version
Final published version
Abstract
Ignition implosions on the National Ignition Facility [ J. D. Lindl et al. Phys. Plasmas 11 339 (2004)] are underway with the goal of compressing deuterium-tritium fuel to a sufficiently high areal density (ρR) to sustain a self-propagating burn wave required for fusion power gain greater than unity. These implosions are driven with a very carefully tailored sequence of four shock waves that must be timed to very high precision to keep the fuel entropy and adiabat low and ρR high. The first series of precision tuning experiments on the National Ignition Facility, which use optical diagnostics to directly measure the strength and timing of all four shocks inside a hohlraum-driven, cryogenic liquid-deuterium-filled capsule interior have now been performed. The results of these experiments are presented demonstrating a significant decrease in adiabat over previously untuned implosions. The impact of the improved shock timing is confirmed in related deuterium-tritium layered capsule implosions, which show the highest fuel compression (ρR~1.0 g/cm[superscript 2]) measured to date, exceeding the previous record [ V. Goncharov et al. Phys. Rev. Lett. 104 165001 (2010)] by more than a factor of 3. The experiments also clearly reveal an issue with the 4th shock velocity, which is observed to be 20% slower than predictions from numerical simulation.
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.108.215004
