Indirect Drive Inertial Confinement Fusion Experiments on the National Ignition Facility (NIF) have achieved a burning plasma state with neutron yields exceeding 170 kJ, roughly 3 times the prior record and a necessary stage for igniting plasmas. The results are achieved despite multiple sources of degradations that lead to high variability in performance. Results shown here, for the first time, include an empirical correction factor for mode-2 asymmetry in the burning plasma regime in addition to previously determined corrections for radiative mix and mode-1.
View Article and Find Full Text PDFPhys Rev Lett
February 2024
Landmark-based geometric morphometrics is widely used to study the morphology of the endocast, or internal mold of the braincase, and the diversity associated with this structure across vertebrates. Landmarks, as the basic unit of such methods, are intended to be points of correspondence, selected depending on the question at hand, whose proper definition is essential to guarantee robustness and reproducibility of results. In this study, 20 landmarks are defined to provide a framework to analyze the morphological variability in squamate endocasts.
View Article and Find Full Text PDFWe present measurements of ice-ablator mix at stagnation of inertially confined, cryogenically layered capsule implosions. An ice layer thickness scan with layers significantly thinner than used in ignition experiments enables us to investigate mix near the inner ablator interface. Our experiments reveal for the first time that the majority of atomically mixed ablator material is "dark" mix.
View Article and Find Full Text PDFVertebrate endocasts are widely used in the fields of paleoneurology and comparative neuroanatomy. The validity of endocranial studies is dependent upon the extent to which an endocast reflects brain morphology. Due to the variable neuroanatomical resolution of vertebrate endocasts, direct information about the brain morphology can be sometimes difficult to assess and needs to be investigated across lineages.
View Article and Find Full Text PDFWe present the design of the first igniting fusion plasma in the laboratory by Lawson's criterion that produced 1.37 MJ of fusion energy, Hybrid-E experiment N210808 (August 8, 2021) [Phys. Rev.
View Article and Find Full Text PDFAn inertial fusion implosion on the National Ignition Facility, conducted on August 8, 2021 (N210808), recently produced more than a megajoule of fusion yield and passed Lawson's criterion for ignition [Phys. Rev. Lett.
View Article and Find Full Text PDFThe petrosal lobules (in whole or part homologous with the paraflocculi) of the cerebellum regulate functions associated with vision including smooth pursuit and velocity control of eye movements, suggesting a possible relationship between the petrosal lobules and behavioral adaptation. Previous studies have produced diverging conclusions regarding the lobules' ecological signal. The current study examines lobule scaling within an ecologically diverse but phylogenetically constrained sample of extant mammals to determine whether ecology influences relative petrosal lobule size.
View Article and Find Full Text PDFObtaining a burning plasma is a critical step towards self-sustaining fusion energy. A burning plasma is one in which the fusion reactions themselves are the primary source of heating in the plasma, which is necessary to sustain and propagate the burn, enabling high energy gain. After decades of fusion research, here we achieve a burning-plasma state in the laboratory.
View Article and Find Full Text PDFInertial confinement fusion implosions must achieve high in-flight shell velocity, sufficient energy coupling between the hot spot and imploding shell, and high areal density (ρR=∫ρdr) at stagnation. Asymmetries in ρR degrade the coupling of shell kinetic energy to the hot spot and reduce the confinement of that energy. We present the first evidence that nonuniformity in the ablator shell thickness (∼0.
View Article and Find Full Text PDFThe first cryogenic deuterium and deuterium-tritium liquid layer implosions at the National Ignition Facility (NIF) demonstrate D_{2} and DT layer inertial confinement fusion (ICF) implosions that can access a low-to-moderate hot-spot convergence ratio (12
Direct measurements of hydrodynamic instability growth at the fuel-ablator interface in inertial confinement fusion (ICF) implosions are reported for the first time. These experiments investigate one of the degradation mechanisms behind the lower-than-expected performance of early ICF implosions on the National Ignition Facility. Face-on x-ray radiography is used to measure instability growth occurring between the deuterium-tritium fuel and the plastic ablator from well-characterized perturbations.
View Article and Find Full Text PDFRecent experiments on the National Ignition Facility [M. J. Edwards et al.
View Article and Find Full Text PDFExperiments have recently been conducted at the National Ignition Facility utilizing inertial confinement fusion capsule ablators that are 175 and 165 μm in thickness, 10% and 15% thinner, respectively, than the nominal thickness capsule used throughout the high foot and most of the National Ignition Campaign. These three-shock, high-adiabat, high-foot implosions have demonstrated good performance, with higher velocity and better symmetry control at lower laser powers and energies than their nominal thickness ablator counterparts. Little to no hydrodynamic mix into the DT hot spot has been observed despite the higher velocities and reduced depth for possible instability feedthrough.
View Article and Find Full Text PDFThe first measurements of multiple, high-pressure shock waves in cryogenic deuterium-tritium (DT) ice layered capsule implosions on the National Ignition Facility have been performed. The strength and relative timing of these shocks must be adjusted to very high precision in order to keep the DT fuel entropy low and compressibility high. All previous measurements of shock timing in inertial confinement fusion implosions [T.
View Article and Find Full Text PDFThe National Ignition Facility has been used to compress deuterium-tritium to an average areal density of ~1.0±0.1 g cm(-2), which is 67% of the ignition requirement.
View Article and Find Full Text PDFPhys Rev B Condens Matter
March 1989
Phys Rev B Condens Matter
February 1988
J Obstet Gynecol Neonatal Nurs
December 1985
Sixty-six primiparous adolescent mothers, aged 14 to 18 years, were asked to identify what they felt they needed to know about caring for themselves and their infant during the first six weeks postpartum. Data were collected by a structured questionnaire. Responses were classified according to four categories: infant medical needs, mother-infant psychosocial needs, maternal physical needs, and daily physical infant care.
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