362 research outputs found

    Multi-imaging x-ray streak camera for ultrahigh-speed two dimensional x-ray imaging of imploded core plasmas(invited)

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    Copyright 2004 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Review of Scientific Instruments, 75(10), 3921-3925, 2004 and may be found at http://dx.doi.org/10.1063/1.178924

    Implosion hydrodynamics of fast ignition targets

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    Copyright 2005 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 12(5), 056312, 2005 and may be found at http://dx.doi.org/10.1063/1.189695

    Reframing human rights: the global network of moral conservative homeschooling activists

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    In this article, we investigate the composition and actions of a principled issue network within the field of human rights that uses rights-claims to pursue traditionalist goals: the moral conservative pro-homeschooling network. We analyse the rising importance of homeschooling within the global moral conservative movement and examine the transnationalization of pro-homeschooling advocacy. We show that the transnational homeschooling advocacy network, while not successful in court cases, has managed to establish home education as part of a global conservative agenda and has made incursions into redefining the terms of the debate within international organizations. Moral conservative homeschooling advocates use a vocabulary of rights and freedoms, and even of moral pluralism, but in the conservative reading human rights are reframed and used to defend a pro-family agenda that establishes the patriarchal family as the ultimate source of authority and the primary carrier of rights

    Assessment of ion kinetic effects in shock-driven inertial confinement fusion implosions using fusion burn imaging

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    The significance and nature of ion kinetic effects in D3He-filled, shock-driven inertial confinement fusion implosions are assessed through measurements of fusion burn profiles. Over this series of experiments, the ratio of ion-ion mean free path to minimum shell radius (the Knudsen number, NK) was varied from 0.3 to 9 in order to probe hydrodynamic-like to strongly kinetic plasma conditions; as the Knudsen number increased, hydrodynamic models increasingly failed to match measured yields, while an empirically-tuned, first-step model of ion kinetic effects better captured the observed yield trends [Rosenberg et al., Phys. Rev. Lett. 112, 185001 (2014)]. Here, spatially resolved measurements of the fusion burn are used to examine kinetic ion transport effects in greater detail, adding an additional dimension of understanding that goes beyond zero-dimensional integrated quantities to one-dimensional profiles. In agreement with the previous findings, a comparison of measured and simulated burn profiles shows that models including ion transport effects are able to better match the experimental results. In implosions characterized by large Knudsen numbers (NK3), the fusion burn profiles predicted by hydrodynamics simulations that exclude ion mean free path effects are peaked far from the origin, in stark disagreement with the experimentally observed profiles, which are centrally peaked. In contrast, a hydrodynamics simulation that includes a model of ion diffusion is able to qualitatively match the measured profile shapes. Therefore, ion diffusion or diffusion-like processes are identified as a plausible explanation of the observed trends, though further refinement of the models is needed for a more complete and quantitative understanding of ion kinetic effects

    Integrated data requirements for natural resource management

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    We do not have sufficient data to adequately describe the integrated socio-ecologicalsystems that support us. It is prohibitively expensive to collect enough data to describe all,so it is important to think strategically about how to (i) use the information we do have and (ii) prioritise the collection of new data. We aim to help by finding efficient ways of improving the information that is available for policy-makers to generate better human–nature outcomes

    Core conditions for alpha heating attained in direct-drive inertial confinement fusion

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    It is shown that direct-drive implosions on the OMEGA laser have achieved core conditions that would lead to significant alpha heating at incident energies available on the National Ignition Facility (NIF) scale. The extrapolation of the experimental results from OMEGA to NIF energy assumes only that the implosion hydrodynamic efficiency is unchanged at higher energies. This approach is independent of the uncertainties in the physical mechanism that degrade implosions on OMEGA, and relies solely on a volumetric scaling of the experimentally observed core conditions. It is estimated that the current best-performing OMEGA implosion [Regan et al., Phys. Rev. Lett. 117, 025001 (2016)10.1103/PhysRevLett.117.025001] extrapolated to a 1.9 MJ laser driver with the same illumination configuration and laser-target coupling would produce 125 kJ of fusion energy with similar levels of alpha heating observed in current highest performing indirect-drive NIF implosions.United States. Department of Energy (DE-FC02-04ER54789)United States. National Nuclear Security Administration (DE-NA0001944
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