UKAEA Papers

Showing 741 - 750 of 1892 UKAEA Paper Results
2017
CCFE-PR(17)45
"A study of helium bubble production in 10keV He+ irradiated tungsten"

X. Yi K. Arakawa D. Nguyen-Manh F. Ferroni P. Liu W. Han F. Wan S. G. Roberts

Helium bubble production in tungsten has been studied combining transmission electron microscopy and in situ irradiations with 10 keV He+ ions. The irradiations were carried out at four temperatures (773 K, 1073 K, 1273 K, 1473 K), and were held at intervals of (0.45; 0.9; 1.2; 1.5) × 1020 He+/m2 for each temperature. Based on detailed analyses of…

Preprint Published
2017
CCFE-PR(17)55
"Simulation and Modelling in High Entropy Alloys"

I. Toda-Caraballo Jan S. Wróbel Duc Nguyen-Manh Pablo Pérez P. E. J. Rivera-Díaz-del-Castillo

High Entropy Alloys (HEAs) is a fascinating field of research, with an increasing number of new alloys discovered. This would hardly be conceivable without the aid of materials modeling and the computational alloy design to investigate the immense compositional space. The simplicity of the microstructure achieved contrasts with the enormous complex…

Preprint Purchase
2016
CCFE-PR(16)81
"Recent developments of in-vessel calibration of mid-IR cameras at JET"

I. Balboa S. Silburn P. Drewelow V. Huber A. Huber D. Kinna M. Price G. F. Matthews S. Collins J. Fessey M. Rack P. Trimble K.D. Zastrow

Recent improvements in software tools and methodology have allowed us to perform a more comprehensive in-vessel calibration for all mid-infrared camera systems at JET. A comparison of experimental methods to calculate the non-uniformity correction is described as well as the linearity for the different camera systems. Measurements of the temperatur…

Preprint Published
2016
CCFE-PR(16)84
"An FPGA-based bolometer for the MAST-U Super-X divertor"

J. Lovell G. Naylor A. Field P. Drewelow R. Sharples JET Contributors

A new resistive bolometer system has been developed for MAST-Upgrade. It will measure radiated power in the new Super-X divertor, with millisecond time resolution, along 16 vertical and 16 horizontal lines of sight. The system uses a Xilinx Zynq-7000 series Field-Programmable Gate Array (FPGA) in the D-TACQ ACQ2106 carrier to perform real time data…

Preprint Published
2016
CCFE-PR(16)25
"Multimachine Data–Based Prediction of High-Frequency Sensor Signal Noise for Resistive Wall Mode Control in ITER"

Y. Liu S.A. Sabbagh I.T. Chapman S. Gerasimov Y. Gribov T.C. Hender V. Igochine M. Maraschek G. Matsunag M. Okabayashi E.J. Strait

The high-frequency noise measured by magnetic sensors, at levels above the typical frequency of resistive wall modes, is analyzed across a range of present tokamak devices including DIII-D, JET, MAST, ASDEX Upgrade, JT-60U, and NSTX. A high-pass filter enables identification of the noise component with Gaussian-like statistics that shares certain c…

Preprint Purchase
2016
CCFE-PR(16)12
"Predictive Nonlinear Studies of TAE Induced Alpha-Particle Transport in the Q=10 ITER Baseline Scenario"

M. Fitzgerald S.E. Sharapov P. Rodrigues D. Borba

We use the HAGIS code to compute the nonlinear stability of the Q=10 ITER baseline scenario to toroidal Alfveneigenmodes (TAE) and the subsequent effects of these modes on fusion alpha-particle redistribution. Our calculations build upon an earlier linear stability survey [Rodrigues, P. et al. (2015). Nuclear Fusion, 55(8), 083003] which provides a…

Preprint Published
2016
CCFE-PR(16)14
"Scrape Off Layer Profiles Interpreted with filament Dynamics"

F. Militello J.T. Omotani

A theoretical framework is developed to link the density profiles in the Scrape Off Layer (SOL) with the fluctuations (filaments) that generate them. The framework is based on the dynamics of independent filaments and their statistical behaviour and can be used to rigorously understand the mechanisms that lead to attending and broadening of the SOL…

Preprint Published
2016
CCFE-PR(16)82
"The global build-up to intrinsic ELM bursts and comparison with pellet triggered ELMs seen in JET"

S.C. Chapman R.O. Dendy P.T. Lang N.W. Watkins F.A. Calderon

We focus on JET plasmas in which ELMs are triggered by pellets in the presence of ELMs which occur naturally. We perform direct time domain analysis of signals from fast radial field coils and toroidal full flux azimuthal loops. These toroidally integrating signals provide simultaneous high time resolution measurements of global plasma dynamics and…

Preprint Published
2016
CCFE-PR(16)79
"Electron cyclotron emission spectra in X- and O-mode polarisation at JET: Martin- Puplett interferometer, absolute calibration, revised uncertainties, inboard/outboard temperature profile, and wall properties"

S. Schmuck J. Fessey J. E. Boom L. Meneses P. Abreu E. Belonohy I. Lupelli

At the tokamak Joint European Torus (JET), the electron cyclotron emission spectra in O-mode and X-mode polarisations are diagnosed simultaneous in absolute terms for several harmonics with two Martin-Puplett interferometers. From the second harmonic range in X-mode polarisation, the electron temperature profile can be deduced for the outboard side…

Preprint Published
2016
CCFE-PR(16)39
"Fast, vacancy-free climb of prismatic dislocation loops in bcc metals"

T. D. Swinburne K. Arakawa H. Mori H. Yasuda M. Isshiki Kouji Mimura Masahito Uchikoshi Sergei L. Dudarev

Vacancy-mediated climb models cannot account for the fast, direct coalescence of dislocation loops seen experimentally. An alternative mechanism, self climb, allows prismatic dislocation loops to move away from their glide surface via pipe diffusion around the loop perimeter, independent of any vacancy atmosphere. Despite the known importance of se…

Preprint Published