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UKAEA-CCFE-PR(18)252018
The evolution of the defect microstructure in materials at high temperature is dominated by diffusion-mediated interactions between dislocations, vacancy clusters and surfaces. This gives rise to complex non-linear couplings between interstitial and vacancy-type dislocation loops, cavities and the field of diffusing vacancies that adiabatically fol…
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UKAEA-CCFE-PR(18)152018
Particle transport is of a great importance for understanding physics of tokamak plasmas and planning future experiments on larger machines such as ITER. The subject was intensively studied in the past, particularly in relation to density peaking and presence of anomalous inward particle convection in L- and H-mode. While in the L-mode case presenc…
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UKAEA-CCFE-PR(18)52018
As shown experimentally, the interplay between screw and edge dislocations in uranium dioxide (UO2) determines the low-temperature plasticity in this material. For the latter, neither the mobility of screw dislocations nor the mechanisms of their glide had been assessed — up until now. It is particularly interesting to evaluate the mobility of 1/…
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UKAEA-RACE-PR(18)012018
The first advanced robot many of us will experience may well be an autonomous vehicle (or driverless car). Autonomous Vehicle (AV) technology has made huge strides in recent years moving from a mainstay of science fiction to the first forays on public roads. The promise in AV stems from a wide range of potential and perceived benefits, the bigges…
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UKAEA-CCFE-PR(18)142018
Measurements are reported of electromagnetic emission close to the cyclotron frequency of energetic ions in JET plasmas heated by waves in the ion cylotron range of frequencies (ICRF). Hydrogen was the majority ion species in all of these plasmas. The measurements were obtained using a sub-harmonic arc detection (SHAD) system in the transmission li…
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UKAEA-CCFE-PR(18)392018
Tungsten has long been the favoured armour material for plasma facing high heat flux components proposed for future fusion reactors, but studies examining the use of tungsten or other refractory metals in the underlying cooled structures have historically excluded them, leaving current concepts heavily dependent on copper alloys such as copper chro…
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UKAEA-CCFE-PR(18)462018
Some of the main plasma physics challenges associated with achieving the conditions for commercial fusion power in tokamaks are reviewed. The confinement quality is considered to be a key factor, having an impact on the size of the reactor and exhaust power that has to be managed. Plasma eruptions can cause excessive erosion if not mitigated, with …
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UKAEA-CCFE-PR(18)382018
Conventional linear elasticity theory predicts the strain fields of a dislocation core to diverge, whereas it is known from atomistic simulations that strains at dislocation cores remain finite. We present an analytical solution to a generalised, variational Peierls-Nabarro model of edge dislocation displacement fields that features a finite core w…
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UKAEA-CCFE-PR(18)102018
In Ion-Temperature-Gradient (ITG) driven turbulence, the resonance condition leads to ion particle turbulent transport coefficients significantly larger than electron particle turbulent transport coefficients. This is shown in non-linear gyrokinetic simulations and explained by an analytical quasilinear model. It is then illustrated by JETTO-QuaLi…
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UKAEA-CCFE-PR(18)502018
There are many sources of random and systematic error in composition quantification by atom probe, however, often only statistical error is reported. Identification of ions and overlaps or interferences of peaks in the mass spectrum are one major source of uncertainty much larger than counting error. These overlaps can be solved using maximum likel…
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