Title: Approaching a burning plasma on the NIF

Abstract

The locus of National Ignition Facility (NIF) inertial confinement fusion (ICF) implosion data, in hot-spot burn-average areal density (ρR) and Brysk temperature (T) space, is shown here and illustrates that several implosions are nearing a burning plasma state, where α-heating is the dominant source of plasma heating. A formula for diagnosing a burning plasma using measured/inferred data from ICF implosion experiments is given with the underlying derivation. Plotting ICF implosion performance against inferred hot-spot energy illustrates the key need to maximize the delivery of energy to an implosion hot-spot. A very compact analytical equation for α-heating is given, which shows that fundamentally, α-heating provides a discrete “boost” to $p{V}^{\gamma }$ of an implosion hot-spot. It is then shown numerically that the analytical expression for the amplification of $p{V}^{\gamma }$ is simply related to yield amplification and to other more famous metrics used for inferring yield amplification in experiments. Interestingly, the argument of the $p{V}^{\gamma }$ boost equation appears to provide a fundamental ignition condition that implicitly includes the effects of asymmetry, and it also exposes the origin of why there is uncertainty in defining single ignition criteria. The resulting analysis of NIF implosion data indicates that an increase in burn-average hot-spot temperature will be needed in order to ignite, and the strategy being pursued to achieve this goal is outlined.

Authors:

Hurricane, O. A.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-8600-5448"

Springer, P. T. ^[1]; Patel, P. K. ^[1]; Callahan, D. A. ^[1]; Baker, K. ^[1]; Casey, D. T. ^[1]; Divol, L. ^[1]; Döppner, T. ^[1]; Hinkel, D. E. ^[1]; Hohenberger, M.  ^[1];

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Berzak Hopkins, L. F.  ^[1];

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Jarrott, C.  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-3894-662X"

Kritcher, A. ^[1]; Le Pape, S. ^[1]; Maclaren, S.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-2022-2212"

Masse, L.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-3587-9671"

Pak, A. ^[1]; Ralph, J. ^[1]; Thomas, C.  ^[1];

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Volegov, P. ^[2] more »; Zylstra, A.  ^[1]

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• Search DOE PAGES for ORCID "0000-0003-0489-7479"

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+ Show Author Affiliations

1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Publication Date:

Thu May 09 00:00:00 EDT 2019

Research Org.:

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1524719

Alternate Identifier(s):

OSTI ID: 1511768

Report Number(s):

LLNL-JRNL-764614
Journal ID: ISSN 1070-664X; 954402

Grant/Contract Number:  

AC52-07NA27344

Resource Type:

Accepted Manuscript

Journal Name:

Physics of Plasmas

Additional Journal Information:

Journal Volume: 26; Journal Issue: 5; Journal ID: ISSN 1070-664X

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY