Showing 1 - 10 of 15 Journals Results
2020
UKAEA-CCFE-PR(20)88
A. R. Jackson A. S. Jacobsen K. G. McClements C. A. Michael M. Cecconello
The efficient confinement of fast ions is crucial to the development of a fusion power plant. Sawtooth crashes are a manifestation of an internal kink instability, which can severely degrade this confinement. The effect of these on a fast ion population can be investigated using fast-ion deuterium-alpha (FIDA) spectroscopy, where charge exchange re…
Preprint2018
UKAEA-CCFE-PR(18)59
Marco Cecconello A. Sperduti I. Fitzgerald S. Conroy S. J. Holm M. Weiszflog
A Neutron Camera (NC) was used on the Mega Ampere Spherical Tokamak (MAST) to measure the DD neutron emissivity along four collimated lines of sight, two on-axis and two off-axis, all viewing the plasma in tangential direction. The encouraging results obtained suggested that an upgraded NC for MAST-U would provide fundamental information for the st…
Preprint Published2018
UKAEA-CCFE-PR(18)40
M. Cecconello W. Boeglin D. Keeling S. Conroy I. Klimek R. V. Perez the MAST team
Experimental evidence is presented of a discrepancy between the predicted and measured D-D fusion products rates on MAST. Both the neutron and proton production rates, measured independently with a neutron camera and charged fusion product detector array, are approximately 40 % lower than those predicted by TRANSP/NUBEAM codes. This deficit is scen…
Preprint Published2015
CCFE-PR(15)117
D. 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 Published2015
CCFE-PR(15)50
O.M. Jones M. Cecconello K.G. McClements I. Klimek R.J. Akers W.U. Boeglin D.L. Keeling A.J. Meakins R.V. Perez S.E. Sharapov M. Turnyanskiy The MAST team
The results of a comprehensive investigation into the effects of toroidicity- induced Alfven eigenmodes (TAE) and energetic particle modes on the NBI-generated fast-ion population in MAST plasmas are reported. Fast-ion redistribution due to frequency-chirping TAE in the range 50 kHz to 100 kHz, and frequency-chirping energetic particle modes known …
Preprint Published2015
CCFE-PR(15)47
K. G. McClements R. J. Akers W.U. Boeglin M. Cecconello D. Keeling O.M. Jones A. Kirk I. Klimek R.V. Perez K. Shinohara K. Tani
The effects of resonant magnetic perturbations (RMPs) on the confinement of energetic (neutral beam) ions in the Mega Amp Spherical Tokamak (MAST) are assessed experimentally using measurements of neutrons, fusion protons and fast ion D _ (FIDA) light emission. In single null-diverted (SND) MAST pulses with relatively low plasma current (400 kA), t…
Preprint Published2014
M. Weiszflog S. Sangaroon M. Cecconello S. Conroy G. Ericsson I. Klimek D. Keeling R. Martin M. Turnyanskiy
This paper presents two different conceptual designs of neutron cameras for Mega Ampere Spherical Tokamak (MAST) Upgrade. The first one consists of two horizontal cameras, one equatorial and one vertically down-shifted by 65 cm. The second design, viewing the plasma in a poloidal section, also consists of two cameras, one radial and the other one w…
Published2014
I. Klimek M. Cecconello S. E. Sharapov J. Harrison G. Ericsson
On MAST, compressional Alfven eigenmodes can be destabilized by the presence of a sufficiently large population of energetic particles in the plasma. This dependence was studied in a series of very similar discharges in which increasing amounts of hydrogen were puffed into a deuterium plasma. A simple method to estimate the isotopic ratio nH/nD usi…
Published2014
R. V. Perez W. U. Boeglin D. S. Darrow M. Cecconello I. Klimek S. Y. Allan R. J. Akers D. L. Keeling K. G. McClements R. Scannell M. Turnyanskiy A. Angulo P. Avila O. Leon C. Lopez O. M. Jones N. J. Conway C. A. Michael
The proton detector (PD) measures 3 MeV proton yield distributions from deuterium-deuterium fusion reactions within the Mega Amp Spherical Tokamak (MAST). The PD’s compact four-channel system of collimated and individually oriented silicon detectors probes different regions of the plasma, detecting protons (with gyro radii large enough to be unco…
Published2014
H.J.C. Oliver S.E. Sharapov R. Akers I. Klimek M. Cecconello The Mast Team
Compressional Alfven and ion-ion hybrid waves excited by energetic beam ions are studied in plasmas with two ion species. In our experiment, a hydrogendeuterium (H-D) plasma is used to produce instabilities similar to those likely to be present in the burning deuterium-tritium plasmas of future tokamaks. Modes are suppressed in the deuterium cyclot…
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