The National Academies Press

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From page 14... ... A complementary, congressionally mandated study on HED research for stockpile stewardship was separately prepared in response to a request in the 2019 National Defense Authorization Act (NDAA) Read the entire page →
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) Read the entire page →
From page 16... ... The rapidly expanding influence of the private sector, developments around the world, and challenges to workplace climate put at risk the approach and laboratories in HED science research that have served the nation well since World War II. Leading Recommendation: To strengthen its global leadership in high energy density (HED) Read the entire page →
From page 17... ... strategy for high energy density science over the next 2 years. This strategy should include benchmarking and the verification and validation of codes, code comparisons, the close integration of simulations using HPC with experi ments, co-development of hardware and software for the research com munity, open-source documentation of codes and experimental results in a standardized open format (e.g., to enhance use and effectiveness of machine learning and artificial intelligence tools) Read the entire page →
From page 18... ... 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. Read the entire page →
From page 19... ... . Finding: HED science has produced spectacular advances in basic science (see, e.g., Table 2-1 and Box 2-3) Read the entire page →
From page 20... ... 51 Origin and Evolution of the Solar System Iron opacity measured, theory and astrophysics applications Nature 517 (2015) 56 Laboratory evidence for the magnetic field of the universe Nat Com 9 (2018) Read the entire page →
From page 21... ... 862 NOTE: ApJ, Astrophysical Journal; ARCMP, Annual Review of Condensed Matter Physics; PNAS, Proceedings of the National Academy of Sciences; PRE, Physical Review E; PRL, Physical Review Letters; RSI, Review of Scientific Instruments; Sci Adv, Science Advances. PHYSICS AND MATERIALS: MATTER MANIPULATION ON THE QUANTUM SCALE Pressure Metallization and Un-metallization One of the most dramatic effects of pressure is the transformation of many chemical elements and compounds into the metallic state, characterized by high electrical conductivity, as well as high opacity to and reflectivity of visible light. Read the entire page →
From page 22... ... The dashed lines labeled Jupiter and Sun show the conditions of temperature and pressure within those bodies; ICF (inertial confinement fusion) indicates the conditions of a capsule undergo ing laser compression. Read the entire page →
From page 23... ... More generally, there is a close relationship between phenomena labeled as the metal-insulator transition of cold or warm-dense matter, continuum lowering in hot-dense plasmas, and electron localization of electrides in chemistry. The differences between these concepts and terminology have made it difficult to understand the relationships between these processes, and the transition between electrically insulating and conducting matter continues to be a rich topic for research in the high energy density realm. Read the entire page →
From page 24... ... surrounded by negatively charged electron orbitals (blue and green) Read the entire page →
From page 25... ... . Sodium is normally a metal opaque to visible light at ambient conditions and at lower p ressures -- for example, at 120 GPa (reflective of visible light) Read the entire page →
From page 26... ... cold compression of atoms to the point that their core electron orbitals begin to combine and hybridize, and (2) compres sion at high enough temperatures that electronic transitions occur between inner atomic core orbitals or mixed core and outer orbitals (see Figure 2-2-1) Read the entire page →
From page 27... ... at which chemical bonding is changed, from static compression using diamond-anvil cells to mechanical impact and laser- and magnetic-driven dynamic compression. Finding: High-quality measurements are possible well into the HED regime, to 0.5-1 TPa statically, and to 1-10 TPa through shock or ramp loading; pio neering laboratory measurements are exploring the 10-100 TPa (0.1-1 billion atmosphere) Read the entire page →
From page 28... ... The difficulty of calculations, which require not only extensive atomic structure but also dense-plasma effects, is compounded by the relatively few atomic physicists who focus on HED conditions. The recent experimental measurement of iron opacity was therefore widely considered a major contribution, not only as a technical accomplishment -- the fact that the opacity of ionized iron could be successfully measured -- but also because it helps address a problem in understanding the Sun's composition. Read the entire page →

From page 14...

... A complementary, congressionally mandated study on HED research for stockpile stewardship was separately prepared in response to a request in the 2019 National Defense Authorization Act (NDAA)