H. Tanabe T. Yamada T. Watanabe K. Gi K. Kadowaki M. Inomoto R. Imazawa M. Gryaznevich R. Scannell N. Conway B. Crowley K. G. McClements I. Fitzgerald C. Michael J. Harrison A. Meakins N. Hawkes T. OGorman F. Cheng Y. Ono The Mast Team
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…
PreprintJ.C. Hillesheim D. Dickinson C.M. Roach S. Saarelma R. Scannell A. Kirk N.A. Crocker W.A. Peebles H. Meyer The MAST Team
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…
Preprint PublishedM. Valovič P.T. Lang A. Kirk W. Suttrop M. Cavedon G. Cseh M. Dunne L.R. Fischer L. Garzotti L. Guimarais G. Kocsis A. Mlynek B. Plőckl R. Scannell T. Szepesi G. Tardini A. Thornton E. Viezzer E. Wolfrum The ASDEX Upgrade team The EUROfusion MST1 team
The complete refuelling of the plasma density loss (pump-out) caused by mitigation of Edge Localised Modes (ELMs) is demonstrated on the ASDEX Upgrade tokamak. The plasma is refuelled by injection of frozen deuterium pellets and ELMs are mitigated by external resonant magnetic perturbations (RMPs). In this experiment relevant dimensionless paramete…
Preprint PublishedM. J. Leyland M. N. A. Beurskens J. C. Flanagan L. Frassinetti K. J. Gibson M. Kempenaars M. Maslov R. Scannell JET Contributors
The Joint European Torus (JET) high resolution Thomson scattering (HRTS) system measures radial electron temperature and density profiles. One of the key capabilities of this diagnostic is measuring the steep pressure gradient, termed the pedestal, at the edge of JET plasmas. The pedestal is susceptible to limiting instabilities, such as Edge Local…
Preprint PublishedH. Tanabe T. Yamada T. Watanabe K. Gi K. Kadowaki M. Inomoto R. Imazawa M. Gryaznevich C. Michael B. Crowley N. J. Conway R. Scannell J. Harrison I. Fitzgerald A. Meakins N. Hawkes K. G. McClements T. OGorman C. Z. Cheng Y. Ono The MAST Team
Electron and ion heating characteristics during merging reconnection startup on the MAST spherical tokamak have been revealed in detail using 130 channel YAG- and 300 channel Ruby-Thomson scattering system and a new 32 chord ion Doppler tomography diagnostic. Detailed 2D profile measurements of electron and ion temperature together with electron de…
Preprint PublishedA. Kirk W. Suttrop I.T. Chapman Yueqiang Liu R. Scannell A.J. Thornton L. Barrera Orte P. Cahyna T. Eich R. Fischer C. Fuchs C. Ham J.R. Harrison MW. Jakubowski B. Kurzan S. Pamela M. Peterka D. Ryan S. Saarelma B. Sieglin M. Valovic M Willensdorfer MAST and ASDEX Upgrade Teams
Sustained Edge Localised Mode (ELM) mitigation has been achieved on MAST and AUG using RMPs with various toroidal mode numbers over a wide range of low to medium collisionality discharges. The ELM energy loss and peak heat loads at the divertor targets have been reduced. The ELM mitigation phase is typically associated with a drop in plasma density…
Preprint PublishedJ.C. Hillesheim F.I. Parra M. Barnes N.A. Crocker H. Meyer W.A. Peebles R. Scannell A. Thornton The MAST Team
Tokamak plasmas rotate even without external injection of momentum. A Doppler backscattering system installed at MAST has allowed this intrinsic rotation to be studied in Ohmic L-mode and Hmode plasmas, including the first observation of intrinsic rotation reversals in a spherical tokamak. Experimental results are compared to a novel 1D model, whic…
Preprint PublishedJ. Milnes N.B. Ayed F. Dhalla G. Fishpool J. Hill I. Katramados R. Martin G. Naylor T. O’Gorman R. Scannell The MAST Upgrade team
The Mega Amp Spherical Tokamak (MAST) is the centre piece of the UK fusion research programme.In 2010, a MAST Upgrade programme was initiated with three primary objectives, to contribute to: (1)testing reactor concepts (in particular exhaust solutions via a flexible divertor allowing Super-X and otherextended leg configurations); (2) adding to the …
Preprint PublishedT. O’Gorman G. Naylor R. Scannell G. Cunningham K. J. Brunner R. Martin D. Croft
A single chord two-color CO2/HeNe (10.6/0.633 µm) heterodyne laser interferometer has been designed to measure the line integral electron density along the mid-plane of the MAST Upgrade tokamak, with a typical error of 1 × 1018 m-3 (~2 phase error) at 4 MHz temporal resolution. To ensure this diagnostic system can be restored from any failures wi…
PublishedP. Bohm M. Aftanas P. Bilkova E. Stefanikova O. Mikulin R. Melich F. Janky J. Havlicek D. Sestak V. Weinzettl J. Stockel M. Hron R. Panek R. Scannell L. Frassinetti A. Fassina G. Naylor M. J. Walsh
The core Thomson scattering diagnostic (TS) on the COMPASS tokamak was put in operation and reported earlier. Implementation of edge TS, with spatial resolution along the laser beam up to~1/100 of the tokamak minor radius, is presented now. The procedure for spatial calibration and alignment of both core and edge systems is described. Several furth…
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