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Title: High-power laser source evaluation

Robust Nuclear-Weapons-Effects Testing (NWET) capability will be needed for the foreseeable future to ensure the performance and reliability, in nuclear environments, of the evolving U.S. stockpile of weapons and other assets. Ongoing research on the use of high-energy lasers to generate environments of utility in nuclear weapon radiation effects simulations is addressed in the work described in this report. Laser-driven hohlraums and a variety of other targets have been considered in an effort to develop NWET capability of the highest possible fidelity in above-ground experiments. The envelope of large-system test needs is shown as the gray region in fig. 1. It does not represent the spectrum of any device; it is just the envelope of the spectral region of outputs from a number of possible devices. It is a goal of our laser-only and ignition-capsule source development work to generate x rays that fall somewhere in this envelope. One of the earlier appearances of this envelope is in ref. 1. The Defense Special Weapons Agency provided important support for the work described herein. A total of $520K was provided in the 1997 IACROs 97-3022 for Source Development and 97-3048 for Facilitization. The period of performance specified in the Statement ofmore » Work ran from 28 February 1997 until 30 November 1997. This period was extended, by agreement with DSWA, for two reasons: 1) despite the stated period of performance, funds were not available at LLNL to begin this work until somewhat later in the fiscal year, and 2) we agreed to stretch the current resources until follow-on funds were in hand, to minimize effects of ramping down and up again. The tasks addressed in this report are the following: 1) Non-ignition-source model benchmarking and design. This involves analysis of existing and new data on laser-only sources to benchmark LASNEX predictions 2) Non-ignition-source development experiments 3) Ignition capsule design to improve total x-ray output and simplify target fabrication 4) Facilitization of source arrays and of the NIF for NWET A funding triad that includes the Defense Special Weapons Agency, the NIF Project and LLNL' s Defense Technology Department supports the work that is reported in this document. The additional work presented here shows how the DSWA-funded work integrates with the larger effort. There has been continued success in the development and fielding of the potentially longer- duration non-ignition beryllium-can sources. There have been advances in understanding of the relevant physics of these underdense radiators as well as further experimental support for the validity of the predictions. This report includes results on our SLIC designs (Seed Layer Ignition Capsules) that permit optimism for prospects of improving the hot-x-ray-to- neutron ratio and total hot x-ray yield for NIF ignition targets. An important summary of the laser-only x-ray environments appears again in this year' s document. This summary serves as an audit trail for the non-ignition-sources that are projected for NIF based on experimental results and on projections of LASNEX modeling.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
OSTI Identifier:
8274
Report Number(s):
UCRL-ID-129096-98
DP0101017; ON: DE00008274
DOE Contract Number:
W-7405-Eng-48
Resource Type:
Technical Report
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE Office of Defense Programs (DP)
Country of Publication:
United States
Language:
English
Subject:
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; 42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; Lasers; Evaluation; Progress Report