G. Szepesi L.C. Appel E. de la Luna L. Frassinetti P. Gaudio M. Gelfusa S. Gerasimov N.C. Hawkes M. Sertoli D. Terranova
Many of the essential data analysis procedures for a tokamak experiment rely on the knowledge of the magnetic field structure obtained from MHD force balance. On JET, the code that is responsible for computing the magnetic equilibrium is called EFIT++. Interpretation of JET data has been challenging due to inconsistencies between diagnostic meas…
PreprintA Thorman E Litherland-Smith S Menmuir N Hawkes M O'Mullane E Delabie B Lomanowski J M Fontdecaba S Scully
Visible emission from a broad range of tungsten charge states has complicated plasma ion temperature and toroidal rotation measurements on the JET tokamak since the installation of the ITER-like wall. A plethora of charge exchange emission lines from ions up to W 56+ and 21 suspected magnetic dipole emission lines have so far been observed. In p…
Preprint PublishedC.D. Challis S. Brezinsek I. Coffey M. Fontana N. Hawkes D. Keeling D. King G. Pucella E. Viezzer JET Contributors
The initial current ramp phase of JET hybrid plasmas is used to optimise the target q-profile for main heating to allow access to high beta and avoid MHD instabilities. Mixed protium-deuterium experiments, carried out at JET since the installation of the beryllium-tungsten wall, have shown that the q-profile evolution during this Ohmic phase varies…
Preprint PublishedC.D. Challis S. Brezinsek I. Coffey N. Hawkes D. Keeling D. King G. Pucella E. Viezzer JET Contributors
The initial Ohmic current ramp phase of JET hybrid plasmas, including a current ‘overshoot’ before the main heating, is used to optimise the q-profile shape to allow access to high β and avoid MHD instabilities [1]. Such hybrid plasmas have never been operated using tritium (T) or mixed deuterium-tritium (D-T) fuel. However, experiments with i…
Preprint PublishedA. Krimmer I. Balboa N. J. Conway M. De Bock S. Friese F. Le Guern N. C. Hawkes D. Kampf Y. Krasikov P. Mertens M. Mittwollen K. Mlynczak J. Oellerich G. Szarvas B. Weinhorst C. Linsmeier
The Charge eXchange Recombination Spectroscopy diagnostic system on the ITER plasma core (CXRS core) will provide spatially resolved measurements of plasma parameters. The optical front-end is located in upper port 3 and the light of 460 nm to 665 nm is routed to spectrometers housed in the tritium building. This paper describes the layout of the o…
Preprint PublishedN. C. Hawkes E. Delabie S. Menmuir C. Giroud A. Meigs N. Conway T. M. Biewer D. L. Hillis
Charge-exchange spectroscopy on JET has become particularly challenging with the introduction of the ITER-like wall. The impurity spectra are weaker and contaminated by many tungsten lines. We have therefore upgraded the instrumentation to allow the simultaneous measurement of impurity and fuel-ion charge exchange by splitting the light between two…
Preprint PublishedDL Keeling CD Challis I Jenkins NC Hawkes I Lupelli C Michael MFM. de Bock the MAST Team JET contributors
Experiments have been carried out on the MAST and JET tokamaks intended to compare the electrical resistivity of the plasma with theoretical formulations. The tests consist of obtaining motional stark effect (MSE) measurements in MHD-free plasmas during plasma current ramp-up (JET and MAST), ramp-down (MAST) and in stationary state (JET and MAST). …
Preprint PublishedH. Tanabe T. Yamada T. Watanabe K. Gi 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. O'Gorman C. Z. Cheng Y. Ono The MAST team
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…
Preprint PublishedH. 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…
PreprintH. 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 Published