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2005
The accuracy of process measurements of tritium with conventional ion chambers is often affected by surface tritium contamination. The measurement of tritium in the exhaust of the JET torus is particularly difficult due to surface contamination with highly tritiated hydrocarbons. JET’s first unsuccessful attempt to overcome the contamination prob…
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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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2005
Self-consistent simulations of the International Thermonuclear Experimental Reactor (ITER) [R.Aymar, P. Barabaschi, and Y. Shimomura, Plasma Phys. Controlled Fusion 44, 519 (2002)] have been carried out using the JETTO-integrated modeling code in which theory-motivated models are used for the H-mode pedestal and for the stability conditions that le…
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2005
Tritium accumulating in codeposits in the gaps between plasma facing components is a safety concern in next step fusion machines as suitable removal techniques have yet not been developed. We report on Imaging Plate measurements of the tritium areal distribution on the side surface of graphite/CFC tiles installed in the TFTR bumper limiter and JET …
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2005
The structure of amorphous In x Se y alloys has been studied by a first principles tight-binding molecular dynamics technique. The three-dimensional amorphous structures with different densities at different compositions were prepared by quick quenching from the liquid phase. The characteristics of short-range order, namely radial distribution func…
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