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2005
We have investigated the electronic structure of MoSi2, Mo5Si3, Mo3Si, and Mo(Si1−xAlx)2 alloys at a range of x values using a combination of valence-band x-ray photoelectron spectroscopy sVBXPSd and densityfunctional theory. We find good agreement between the experimental spectra and the calculated total densities of states. The observed differe…
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2005
A set of external coils (A-coils) capable of producing nonaxisymmetric, predominantly n =1, fields with different toroidal phase and a range of poloidal mode m spectra has been used to determine the threshold amplitude for mode locking over a range of plasma parameters in Alcator C-Mod [I. H. Hutchinson, R. Boivin, F. Bombarda, P. Bonoli, S. Fairfa…
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2005
We present calculations of the transmutation of initially pure tungsten first-wall and divertor plasma-facing armor intoW-Re-Os alloys in the European Union Power Plant Conceptual Study (PPCS) fusion plant models A, B, and AB. The fusion neutron spectrum was modeled using the MCNP Monte Carlo code including resonance self-shielding effects, and we …
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2005
JET has operated with divertors of differing geometries since 1994. Impurities accumulated in the inner leg of all the divertors, and operation of the first (Mk I) divertor with beryllium tiles demonstrated that most are eroded from the main chamber walls and swept along the scrape-off layer to the inner divertor. Carbon deposited at the inner dive…
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2005
The tight-binding Stoner model of band magnetism is generalized to account for local charge neutrality by working within the tight-binding-bond s TBB d representation of the binding energy. We show that the analytic forces within this TBB Stoner model take a very simple form because neither the renormalization in the on-site energies due to local c…
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2005
Nonlinear three-dimensional electromagnetic simulations are employed to study the dynamics of edge localized modes (ELMs) driven by intermediate wavelength peeling-ballooning modes. It is found that the early behavior of the modes is similar to expectations from linear, ideal peeling-ballooning mode theory, with the modes growing linearly at a frac…
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2004
This Letter provides information on the spatial and temporal structure of periodic eruptions observed in magnetically confined laboratory fusion plasmas, called edge-localized modes (ELMs), and highlights similarities with solar eruptions. Taken together, the observations presented in this Letter provide strong evidence for ELMs being associated wi…
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2004
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2004
The generalized Charney-Hasegawa-Mima equation is unstable to a four wave modulational instability whereby a coherent, monochromatic drift wave can drive a band of modes and associated zonal flows unstable. Although initially the fastest growing modes dominate, a secondary nonlinear instability later drives the longest wavelength zonal flow and its…
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2004
A microwave interferometry technique is applied for the first time for detecting a discrete spectrum of Alfvén cascade (AC) eigenmodes excited with fast ions in reversed magnetic shear plasmas of the Joint European Torus. The interferometry measurements of plasma density perturbations associated with ACs show an unprecedented frequency and time re…
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