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UKAEA-CCFE-PR(19)482018
A 1D model of an RF driven ion source is presented and is based on the ionisation of thermal electrons. The RF source differs from traditional filament and arc ion sources because there are no primary electrons present, and is simply composed of an antenna region (driver) and a main plasma discharge region. However the model does still make use …
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UKAEA-CCFE-PR(19)502019
A model for a beam-driven plasma neutraliser for a 1MeV, 40A beam of D- ions is presented and is based on the dimensions of the ITER gas neutraliser. For the beam-driven plasma neutraliser there is no need for an external power source for producing and sustaining the plasma. Instead the use of high magnetic fields is employed for plasma confinement…
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UKAEA-CCFE-PR(19)492019
EDGE2D-EIRENE (the ‘code’) simulations show that radial electric field, Er, in the near scrape-off layer (SOL) of tokamaks can have large variations leading to a strong local E´B shear greatly exceeding that in the core region. This was pointed out in simulations of JET plasmas with varying divertor geometry, where the magnetic conf…
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UKAEA-CCFE-PR(19)472019
High bandwidth, high spatial resolution measurements of electron temperature, density and plasma potential are valuable for resolving turbulence in the boundary plasma of tokamaks. While conventional Langmuir probes can provide such measurements either their temporal or spatial resolution is limited: the former by the sweep rate necessary for obtai…
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UKAEA-CCFE-PR(19)462019
The effect of plasma shaping on scrape-off layer (SOL) plasma turbulence is investigated through a rigorous validation exercise. Two- and three-dimensional simulations of the SOL plasma dynamics in three TCV limited discharges are carried out with the GBS code. These discharges realize an almost circular magnetic equilibrium, an elongated equilibri…
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UKAEA-CCFE-PR(19)452019
The DEMO blanket attachment concept is challenging due to several factors: the harsh radiation environment, the thermal expansion, the electro-magnetic loads, the remote maintenance feasibility, and the accurate control of the alignment of the breeding blanket first wall during operation. There are two inboard and three outboard blanket segments…
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UKAEA-CCFE-PR(19)442019
The low energy structures of irradiation-induced defects have been studied in detail, as these determine the available modes by which a defect can diffuse or relax. As a result, there are many studies concerning the relative energies of possible defect structures, and empirical potentials are commonly fitted to or evaluated with respect to these en…
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UKAEA-CCFE-PR(19)432019
Body-centered cubic metals and alloys irradiated by energetic particles form highly mobile prismatic dislocation loops with a/2 {111} -type Burgers vectors. We show how to simulate thermal diffusion of prismatic loops using a discrete dislocation dynamics approach that explicitly includes the stochastic forces associated with ambient thermal fluctu…
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UKAEA-CCFE-PR(19)422019
High temperature, neutron irradiated single crystal tungsten, with a post irradiation composition of W-1.20±0.11at.%Re-0.11±0.05at.%Os-0.03±0.01at.%Ta was characterised using a combination of Atom Probe Tomography (APT) and Scanning Transmission Electron Microscopy (STEM). APT showed that within nanoscale clusters of Re/Os, the atomic density wa…
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UKAEA-CCFE-PR(19)412019
A new facility to study the interaction of hydrogen isotopes with nuclear fusion relevant first wall materials, its retention and release, has been produced. The new facility allows implanting a range of gases into samples, including tritium. Accurate study of isotope effects, such as the isotopic exchange in damaged microstructure, has previously …
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