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Title: Probing the Interface Stability of Implosions

Abstract

In the quest for reaching ignition of deuterium-tritium (DT) fuel capsule implosions, experiments on the National Ignition Facility have shown lower final fuel areal densities than simulated. Possible explanations for reduced compression are higher preheat that can increase the ablator-DT ice density jump and induce mix at that interface, or reverberating shocks. We were hence interested in developing x-ray Refraction Enhanced Radiography (RER) to infer the inflight density profiles in layered fuel capsule implosions. The first experiments validated our setup by recording a streaked x-ray fringe pattern from an undriven high density carbon (HDC) capsule consistent with raytracing calculations at the required ~ 6 micron and 25 ps resolution. Streaked RER was then applied to inflight cryogenically layered HDC capsule implosions using a hydrogen-tritium fuel mix. The first RER of an inflight capsule revealed strong features associated with the ablation front and ice-ablator interface that are not visible in standard absorption in-flight radiographs.

Authors:
 [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1479066
Report Number(s):
LLNL-TR-760012
947993
DOE Contract Number:  
AC52-07NA27344
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
Lasers

Citation Formats

Landen, Otto. Probing the Interface Stability of Implosions. United States: N. p., 2018. Web. doi:10.2172/1479066.
Landen, Otto. Probing the Interface Stability of Implosions. United States. https://doi.org/10.2172/1479066
Landen, Otto. 2018. "Probing the Interface Stability of Implosions". United States. https://doi.org/10.2172/1479066. https://www.osti.gov/servlets/purl/1479066.
@article{osti_1479066,
title = {Probing the Interface Stability of Implosions},
author = {Landen, Otto},
abstractNote = {In the quest for reaching ignition of deuterium-tritium (DT) fuel capsule implosions, experiments on the National Ignition Facility have shown lower final fuel areal densities than simulated. Possible explanations for reduced compression are higher preheat that can increase the ablator-DT ice density jump and induce mix at that interface, or reverberating shocks. We were hence interested in developing x-ray Refraction Enhanced Radiography (RER) to infer the inflight density profiles in layered fuel capsule implosions. The first experiments validated our setup by recording a streaked x-ray fringe pattern from an undriven high density carbon (HDC) capsule consistent with raytracing calculations at the required ~ 6 micron and 25 ps resolution. Streaked RER was then applied to inflight cryogenically layered HDC capsule implosions using a hydrogen-tritium fuel mix. The first RER of an inflight capsule revealed strong features associated with the ablation front and ice-ablator interface that are not visible in standard absorption in-flight radiographs.},
doi = {10.2172/1479066},
url = {https://www.osti.gov/biblio/1479066}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Oct 08 00:00:00 EDT 2018},
month = {Mon Oct 08 00:00:00 EDT 2018}
}