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CCFE-PR(16)402016
A non-steady-state orbit-following Monte-Carlo code has been developed. As part of the verification and validation of the code, calculations of time dependent neutron rates have been made for a specific shot in the Mega Amp Spherical Tokamak (MAST) using three-dimensional fields representing vacuum resonant magnetic perturbations (RMPs) and toroida…
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CCFE-PR(16)612016
In the last three years, magnetic reconnection research in the MAST spherical tokamak achieved major progress by use of new 32 chord ion Doppler tomography, 130 channel YAG and 300 channel Ruby Thomson scattering diagnostics. In addition to the previously achieved high power plasma heating during merging, detailed full temperature profile measureme…
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CCFE-PR(16)312016
This paper describes a recent advances in merging/reconnection experiments in MAST, namely tomographic ion Doppler spectroscopy capability from 2013 which solves the problem of the absence of ion temperature profile measurement during the solenoid-less startup. Providing 32 channel line-integrated spectra from 0.25m< rtangential <1.1m are con…
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CCFE-PR(16)482016
In electrostatic simulations of MAST plasma at electron-gyroradius scales, using the local flux-tube gyrokinetic code GS2 with adiabatic ions, we find that the longtime saturated electron heat flux (the level most relevant to energy transport) decreases as the electron collisionality decreases. At early simulation times, the heat flux quasisatura…
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CCFE-PR(16)362016
A number of tools have recently been developed to study equilibrium and stability in tokamaks with pressure anisotropy. Here we apply these tools to a Mega Ampere Spherical Tokamak (MAST) discharge to calculate equilibrium, Alfven continua and eigenmodes, through to linear growth and nonlinear saturation of a toroidal Alfven eigenmode (TAE); this i…
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CCFE-PR(16)252016
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…
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CCFE-PR(17)412016
Four numerical codes are employed to investigate the dynamics of Scrape-Off Layer filaments in tokamak relevant conditions. Experimental measurements were taken in the MAST device using visual camera imaging, which allows the evaluation of the perpendicular size and velocity of the filaments, as well as the combination of density and temperature as…
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CCFE-PR(17)182016
Clear filamentary structures are observed at the edge of tokamak plasmas. These filaments are ejected out radially and carry plasma in the far Scrape Off Layer (SOL) region, where they are responsible for producing most of the transport. A study has been performed of the characteristics of the filaments observed in L-mode plasma on MAST, using visi…
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CCFE-PR(16)272016
Retarding field energy analysers (RFEAs) have been used to compare the ion temperature ( T i ) of large plasma filaments with the background plasma (composed of small scale filaments) at the midplane and divertor target in L mode discharges in the Mega Amp Spherical Tokamak (MAST). At low densities, at the midplane and divertor, at distances from 2…
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CCFE-PR(16)172016
Measurements of local density and magnetic field fluctuations near the pedestal top, conditionally-averaged over the ELM cycle, have been made in MAST. A Doppler backscattering (DBS) system installed at MAST was used to measure intermediate-k (k ? _i _ 3 - 4) density fluctuations at the top of the pedestal. A novel diagnostic technique combining DB…
Showing 111 - 120 of 302 UKAEA Paper Results