Fundamental Research in High Energy Density Science (2023) / Chapter Skim
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Pages 29-49
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From page 29... ...
Another perspective on HED science addresses the role of impacts during the gravitational accumulation of mass as a planet forms. Typical orbital velocities around the Sun show that impacts associated with planet formation generate terapascal-scale pressures; that is, create HED conditions at the planet's growing surface.
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From page 30... ...
REDEFINING CHEMICAL BONDS Low-Temperature Plasma and Electrochemistry The electron distributions between atoms define the chemical bonds in a molecule, solid, liquid, or gas, determining the physical and chemical properties of matter. Not only do HED conditions of high pressure and temperature reshape the distribution of electrons between atoms, relative to ambient conditions, but the electromagnetic fields used to achieve these conditions in laboratory experiments also contribute to changing the electron clouds around atoms.
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From page 31... ...
, and evidence of significant energy being released in ICF experiments is among the most exciting recent breakthroughs in HED science. For the first time, more energy has been produced by nuclear fusion than was directly accessible to the material being compressed.
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From page 32... ...
Finding: NIF, Omega, and Z, the major NNSA HED laser and pulsed-power facilities, are producing breakthrough science, including through their external user programs for Discovery Science. Targets One of the key enabling technologies for performing HED science is the targ etry, which is required in virtually all experiments.
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From page 33... ...
Patel, R Betti, et al., "Physics Principles of Inertial Confinement Fusion (ICF)
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From page 34... ...
Energy yield of 3.15 MJ Target gain ~1.5 3 2.05 MJ of laser energy Fusion Energy Yield (MJ) 2 Max laser energy 1 0 2012 2014 2016 2018 2020 2022 Year FIGURE 2-3-1 Researchers have made huge strides in producing energy from nuclear fusion in the laboratory, with the bar colors representing different design approaches used at the National Ignition Facility.
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From page 35... ...
The significance of HED science is that it greatly enhances the quantum regime of superconductivity, with several room-temperature superconductors having now been discovered at high pressures. In particular, hydrogen-rich compounds are found to exhibit superconductivity at the highest of temperatures, consistent with current HED understanding of hydrogen itself -- these crystalline metal hydrides apparently exhibit some of the exotic quantum properties expected for metallic atomic hydrogen.
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From page 36... ...
The figure shows experimentally measured superconducting transition temperatures as a function of time, with room temperature superconductors having been discovered above 180 GPa pressure by 2020. Although currently synthesized at high pressures, research suggests that it is possible to produce room temperature superconductors at or near ambient conditions.
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From page 37... ...
In short, HED science spun off the modern $500 billion per year computer micro-chip manufacturing industry based on EUV lithography, and the reason that the United States is home to the majority of EUV lithography tools is because of this specific program emerging from the national laboratories and the support provided by it. controlled as a function of pressure and deformation.
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From page 38... ...
The increasing fidelity, flexibility, and reliability of these critical tools -- and the underlying experiments -- is one of the triumphs of HED science. Finding: The integration of approaches from theory, simulation, and experi mentation is critical in the HED regimes, for which the multiplicity of time and lengths scales leads to challenges in understanding basic material properties and macroscale system behavior.
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From page 39... ...
Experiments and theory are intertwined in all three instances, with implications for disciplines ranging from astrophysics and chemistry to condensed-matter, materials, and plasma physics. GRAND CHALLENGES AND OPPORTUNITIES FOR HIGH ENERGY DENSITY SCIENCE Discoveries in HED science that transform the fabric of society materialize when breakthroughs in laboratory and computational technologies can test and put 1 Rather than the inherently negative "gaps" noted in the statement of task, the committee chose to use "opportunities" with the intent that the National Nuclear Security Administration (NNSA)
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From page 40... ...
How can burning fusion plasmas be controlled and harnessed for society's energy, security, and technology needs? Fundamental HED science is essential to the development of the technologies and processes required for controlling nuclear fusion in the laboratory, taking current experiments that are documenting the onset of nuclear ignition to the point of fully exploiting the output of nuclear reactions.
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From page 41... ...
Can we understand the conditions under which life forms and the signatures of planets on which life could emerge? HED science is revealing the violent impact processes by which planets form, with impact sterilization frustrating the early emer gence of life; how planetary interiors and surfaces evolve; and how magnetic fields can be produced, shielding the planet's surface from the charged particles and ionizing radiation emitted by the host star.
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From page 42... ...
A new generation of experiments and model ing, including simulation and theory, is beginning to define the linkages between these different scales, helping to characterize the stability of inertial confinement fusion (ICF) implosions; translating microscopic viscosity estimates to magnetic dynamo processes in planets; defining the strength of bulk matter; and correlating between kinetic, thermal, plasma-wave, Coulomb, and nuclear energy scales in the warm dense matter of low-mass stars.
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From page 43... ...
The energy density of such light already exceeds 1017 J m–3, sur passing by a million-fold the onset of the HED regime described in this report. In interacting with matter, this large energy density represents an enabling technology for HED applications.
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From page 44... ...
Opportunity: Harnessing Star Power in the Laboratory A primary challenge of sparking nuclear fusion is directly related to delivering the energy required to overcome the mutual repulsion of the positively charged nuclei that make up fusion fuel. The current strategy to initiating fusion reactions is to heat fusion fuel to temperatures exceeding a million degrees, forming a hot plasma that is confined for long enough that the energy from these initial reactions can be sustained.
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From page 45... ...
The field of inertial fusion -- unlike its cousin, magnetic confinement fusion -- has strong ties to HED science. Like all HED science, it is massively multi-scale and requires designing, testing, and diagnosing plasma experiments that take fusion fuel and surrounding components from room-temperature (or cryogenic)
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From page 46... ...
But ICF also offers unique opportunities for HED science itself -- the extreme temperatures, densities, and radiation fields created by an igniting plasma lead to new pressure–temperature–radiation regimes that cannot be accessed in other terrestrial environments. Finally, inertial fusion also has deep intellectual ties to stockpile stewardship, which has enabled the United States to maintain a safe, secure, and reliable nuclear weapons stockpile without nuclear explosion testing since 1992.
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From page 47... ...
Extending this density and temperature coverage will make possible extrapolation to yet more extreme conditions, such as those near the degeneracy boundary in white-dwarf stars. Oxygen opacity is a dominant issue for carbon-rich white dwarfs, and such experimental benchmarks will have a significant impact on stellar and white-dwarf modeling.
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From page 48... ...
1H charged-particle breakup take advantage of the diagnostic advances in HED science to measure fundamental
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From page 49... ...
Creating conditions suitable for reliably characterizing laboratory experiments and material properties in this regime is a Grand Challenge. Non-Equilibrium Models and Analysis The vast majority of existing models and measurements assume that materials are in local thermodynamic equilibrium (LTE)
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