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2010
Wepresentgeneralizedstructurefunction(GSF)analysisof magneticandvelocityfieldfluctuationsmeasured insituinthesolarwindat ~ 1 AUwiththeACEspacecraft.Wedecomposethefluctuationsintodirectionsparalleland perpendiculartothemeanlocalbackgroundmagneticfield.GSFplotsbasedonthesequantitiesareshowntoprovideaclear indicatorofthespectralbreakbetweentheinertial…
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2010
Frank-Read sources are among the most important mechanisms of dislocation multiplication, and their operation signals the onset of yield in crystals. We show that the critical stress required to initiate dislocation production falls dramatically at high elastic anisotropy, irrespective of the mean shear modulus. We hence predict the yield stress of…
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2010
Direct coupling between a transport solver and local, nonlinear gyrokinetic calculations using the multiscale gyrokinetic code TRINITY [M. Barnes, “TRINITY: A unified treatment of turbulence, transport, and heating in magnetized plasmas,” Ph.D. thesis, University of Maryland, (2008) eprint arXiv:0901.2868] is described. The coupling of the micr…
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2010
Absolute calibration of LIDAR Thomson scattering systems on large fusion devices may be achieved using rotational Raman scattering. The choice of calibrating gas molecule presents different options and design trade-offs and is likely to be strongly dependent on the laser wavelength selected. Raman scattering of hydrogenic molecules produces a very …
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2009
Tungsten is a strong contender for a plasma-facing material in future fusion power plant designs, and the material of choice for the divertor of ITER, due to its high melting point, thermal conductivity, and resistance to sputtering erosion. Sputtering erosion is a major concern for plasma-facing materials because sputtered atoms could enter the pl…
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2009
Recent studies on the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42 , 614 (2002)] have elucidated key aspects of the dependence of stability, confinement, and density control on the plasma magnetic configuration, leading to the demonstration of nearly noninductive operation for 1 s with pressure 30% above the ideal no-wall stability limit. Achieving…
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2009
Abstract: The effect of beam generated plasma in the channels of the ITER electrostatic residual ion dump (ERID) is investigated. The space charge due to the plasma and the separating positive and negative ion beams could cause the ERID to fail if the plasma density is sufficiently high. The gas density at which this occurs is derived for both the …
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2009
Recent predictions have been made of metallurgical properties of low-activation ferritic/martensitic steels alloys at the high irradiation levels (displacements per atom or dpa) needed for a fusion power plant as based on measurements at low irradiation levels where more data is available. These have been published for the yield stress and for the …
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2009
We derive a model tight-binding many-body d -electron Stoner Hamiltonian for FeCr binary alloys and investigate the sensitivity of its mean-field solutions to the choice of hopping integrals and the Stoner exchange parameters. By applying the local charge-neutrality condition within a self-consistent treatment we show that the negative enthalpy-of-…
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2009
A set of key properties for an ideal dissipation scheme in gyrokinetic simulations is proposed, and implementation of a model collision operator satisfying these properties is described. This operator is based on the exact linearized test-particle collision operator, with approximations to the field-particle terms that preserve conservation laws an…
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