Fundamental Research in High Energy Density Science (2023) / Chapter Skim
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1 High Energy Density Science: Understanding Matter at Extremes
1 High Energy Density Science: Understanding Matter at Extremes
Pages 5-18
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From page 5... ...
At these conditions, the forces between atoms, electrons, ions and even nucleons are profoundly modified, changing fundamental material properties, paving paths to the creation of entirely new forms of matter, and enabling conversion of matter into energy. Traditionally, the domain of HED science is defined by pressures exceeding 1 million times atmospheric pressure (see Figure 1-1)
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From page 6... ...
"Hot dense matter" characterizes the conditions of inertial confinement fusion (ICF) , and of the interiors of the Sun and other stars, with densities that can be more than 100 times those of a typical terrestrial solid at ambient conditions.
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From page 7... ...
The trends of the Periodic Table of chemical elements are thus fundamentally transformed in the HED regime, with new materials, properties, and processes being observed. Hydrogen and helium, the most abundant chemical elements in the universe, trans form to fluid metals at HED conditions, for example, with liquid metallic hydrogen being the predominant constituent of stars and giant planets (see Figure 1-2)
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From page 8... ...
The TPa = 1,000 GPa pressures now accessible in a variety of laboratory experiments (see Chapter 2) are comparable to the quantum mechanical forces determining the structure of the atom: ħ2/(4πmea05)
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occurs alongside thermal ionization (atoms losing electrons due to heating) , and ions can simultaneously exhibit properties pertinent to both fluids and solids.
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HED experiments use gem-quality diamonds to compress materials into the 0.1-1 TPa pressure range, and capsules of nanocrystalline diamond containing solidified hydrogen isotopes (deuterium and tritium or "DT" ice) are used as targets for inertial confine ment fusion (ICF)
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From page 11... ...
Thus, it is not sufficient to understand the microphysics of HED science: we must also understand how samples interact with external fields; how inhomogeneous radiation distributions influence plasma evolution; and how instabilities form, grow, and evolve into turbulence and mix. This variety of phenomena -- from the quantum mechanics of chemical bond ing, to collective plasma effects, to strong coupling of matter with radiation, to thermonuclear processes, along with the enormous ranges of relevant length and time scales, from the atomic to the astrophysical -- leads to some of the fundamental excitement of HED science.
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In anticipation of continued advances in both computational and experimental capabilities, the committee prepared this report to assess the accomplishments, opportunities, and challenges of basic research in HED science. In addition, HED science has applications in core mission areas of the NNSA, including stewardship of the nation's nuclear weapons stockpile, countering pro liferation of the associated technologies, and development of nuclear fusion–based energy capabilities: areas in which the basic research described in the text by the BOX 1-3 The Language of High Energy Density Science Atomic pressures.
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From page 13... ...
Matter typically at "classical" conditions, neither quantum nor thermonuclear, roughly at temperatures of 102-106 K ≈ 1-100 eV energies. Warm dense matter is the regime of this matter above ~100 GPa at which several energy scales are comparable, including the Coulomb, thermal, Fermi, and plasmon energies.
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From page 14... ...
STATEMENT OF TASK AND IMPLEMENTATION This study is in response to Section 3137 of the 2020 NDAA (Public Law 116-92) requesting that the NNSA engage the National Academies to produce an unclassified, publicly available assessment of recent advances and the current status of research in the field of HED physics.
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From page 15... ...
The committee will consider HED physics as the physics of matter and radiation at energy densities exceeding 1 × 1011 J/m3 or other tempera ture and pressure ranges within the warm dense matter regime. It will include a particular focus on HED material phases, plasmas atypical of astrophysical condi tions, and conditions of interest to the National Nuclear Security Administration (NNSA)
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From page 16... ...
science and address future national needs, the NNSA should exploit and enhance the capabilities of its flagship HED facilities (e.g., the National Ignition Facility, Z Pulsed Power Facility, and Omega Laser Facility) by establishing plans over the next 5 years for (1)
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From page 17... ...
that access a range of time and length scales. Major Recommendation: The inertial confinement fusion community should redouble efforts to focus on the underlying basic science to (1)
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READER'S GUIDE AND NOTE ON APPENDIXES The report is organized into five chapters and several appendixes. Mirroring the study's statement of task, Chapter 2 summarizes recent progress in the field; Chap ter 3 points to opportunities to pursue, which also reflect current gaps; Chapter 4 considers the HED science workforce; and Chapter 5 addresses the international HED science landscape.
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