H. 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 PublishedD. L. Keeling T. R. Barrett M. Cecconello C. D. Challis N. Hawkes O. M. Jones I. Klimek K. G. McClements A. Meakins J. Milnes M. Turnyanskiy The MAST team
The phenomenon of redistribution of neutral beam fast-ions due to MHD activity in plasma has been observed on many tokamaks and more recently has been a focus of research on MAST ( Turnyanskiy M. et al, 2013 Nucl. Fusion 53 053016 ). n=1 fishbone modes are observed to cause a large decrease in the neutron emission rate indicating to exist a signifi…
Preprint PublishedJ.C. Hillesheim N. A. Crocker W.A. Peebles H. Meyer A. Meakins A.R. Field D. Dunai M. Carr N. Hawkes The MAST Team
The high-k (7 . k??i . 11) wavenumber spectrum of density fluctuations has been measured for the first time in MAST [B. Lloyd et al, Nucl. Fusion 43, 1665 (2003)]. This was accomplished with the first implementation of Doppler backscattering (DBS) for core measurements in a spherical tokamak. DBS has become a well-established and versatile diagnost…
Preprint PublishedC.D. Challis J. Garcia M. Beurskens P. Buratti E. Delabie P. Drewelow L. Frassinetti C. Giroud N. Hawkes J. Hobirk E. Joffrin D. Keeling D.B. King C.F. Maggi J. Mailloux C. Marchetto D. McDonald I. Nunes G. Pucella S. Saarelma J. Simps
The replacement of the JET carbon wall (C-wall) by a Be/W ITER-like wall (ILW) has affected the plasma energy confinement. To investigate this, experiments have been performed with both the C-wall and ILW to vary the heating power over a wide range for plasmas with different shapes. It was found that the power degradation of thermal energy confinem…
Preprint PublishedS. Menmuir C. Giroud T. M. Biewer I. H. Coffey E. Delabie N. C. Hawkes M. Sertoli JET EFDA Contributors
Charge exchange spectroscopy has long been a key diagnostic tool for fusion plasmas and is well developed in devices with Carbon Plasma-Facing Components. Operation with the ITER-like wall at JET has resulted in changes to the spectrum in the region of the Carbon charge exchange line at 529.06nm and demonstrates the need to revise the core charge e…
PublishedM. Gelfusa A. Murari I. Lupelli N. Hawkes P. Gaudio M. Baruzzo M. Brix T. Craciunescu V. Drozdov A. Meigs E. Peluso M. Romanelli S. Schmuck B. Sieglin JET-EFDA Contributors
One of the main approaches to thermonuclear fusion relies on confining high temperature plasmas with properly shaped magnetic fields. The determination of the magnetic topology is, therefore, essential for controlling the experiments and for achieving the required performance. In Tokamaks, the reconstruction of the fields is typically formulated as…
PublishedP. Mantica C. Angioni C. Challis G. Colyer L. Frassinetti N. Hawkes T. Johnson M. Tsalas P. C. Devries J. Weiland B. Baiocchi M. N. A. Beurskens A. C. A. Figueiredo C. Giroud J. Hobirk E. Joffrin E. Lerche V. Naulin A. G. Peeters A. Sal
New transport experiments on JET indicate that ion stiffness mitigation in the core of a rotating plasma, as described by Mantica et al. [ Phys. Rev. Lett. 102, 175002 (2009) ] results from the combined effect of high rotational shear and low magnetic shear. The observations have important implications for the understanding of improved ion core con…
PublishedM. F. M. De Bock N. J. Conway M. J. Walsh P. G. Carolan N. C. Hawkes
A multichord motional Stark effect MSE system has recently been built on the MAST tokamak. In MAST the π and σ lines of the MSE spectrum overlap due to the low magnetic field typical for present day spherical tokamaks. Also, the field curvature results in a large change in the pitch angle over the observation volume. The measured polarization ang…
PublishedRJ.E. Jaspers M.G. Von Hellermann E. Delabie J.E. Boom Aj.H. Donne W. Biel N.C. Hawkes O. Neubauer M. Di Maio S. Sadakov F. Klinkhamer B. Snijders A. Hogenbirk
Charge eXchange Recombination Spectroscopy (CXRS) will play a crucial role in the diagnosing of burning plasmas: items like helium ash, transport barriers, impurity content or fuel ratio can all be assessed with CXRS. In fact this is the only direct method to obtain information about the light impurity ions, such as temperature, concentrations and …
PublishedM.G. Von Hellermann E.Delabie R.J.E. Jaspers W.Biel O.Marchuk H.P.Summers A.Whlteford C.Giroud N.C.Hawkes K.D.Zastrow
Charge exchange Recombination Spectroscopy (CXRS) plays a pivotal role in the diagnostics of hot fusion plasmas and is implemented currently in most of the operating devices. In the present report the main features of CXRS are summarized and supporting software packages encompassing "Spectral Analysis Code CXSFIT", "Charge Exchange Analysis Package…
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