T. O’Gorman P. J. Mc Carthy S. Prunty M. J. Walsh M. R. Dunstan R. B. Huxford G. Naylor Emmanuel Maguet R. Scannell S. Shibaev
A major upgrade to the ruby Thomson scattering (TS) system has been designed and implemented on the Mega-ampere spherical tokamak (MAST). MAST is equipped with two TS systems, a Nd:YAG laser system and a ruby laser system. Apart from common collection optics each system provides independent measurements of the electron temperature and density profi…
PublishedJ. Figueiredo G. Naylor M. Walsh M. Dunstan R. Scannell F. Serra
The recent upgrade to the MAST YAG Thomson scattering while enhancing the diagnostic capabilities increased the complexity of the system. There are eight YAG lasers now operational, doubling the number from the previous setup. This means alignment between each laser individually and reference points is essential to guarantee data quality and diagno…
PublishedR. Scannell M. J. Walsh M. R. Dunstan J. Figueiredo G. Naylor T. O’Gorman K. J. Gibson H. Wilson S. Shibaev
A Thomson scattering diagnostic designed to measure both edge and core physics has been implemented on MAST. The system uses eight Nd:YAG lasers, each with a repetition rate of 30 Hz. The relative and absolute timing of the lasers may be set arbitrarily to produce fast bursts of measurements to suit the time evolution of the physics being studied. …
PublishedA. R. Field J. Mccone N. J. Conway M. Dunstan S. Newton M. Wisse
Neo-classical tokamak plasma theory predicts poloidal rotation driven by the temperature gradient of order ~ few km/s. In conventional aspect ratio tokamak plasmas, e.g. on JET and DIII-D, poloidal velocities considerably in excess of the neo-classical values have been measured, particularly in the presence of internal transport barriers (ITBs), by…
PublishedR. Scannell M. J. Walsh P. G. Carolan A. C. Darke M. R. Dunstan R. B. Huxford G. McArdle D. Morgan G. Naylor T. O’Gorman S. Shibaev N. Barratt K. J. Gibson G. J. Tallents H. R. Wilson
A new infrared Thomson scattering system has been designed for the MAST tokamak. The system will measure at 120 spatial points with 10 mm resolution across the plasma. Eight 30 Hz 1.6 J Nd:YAG lasers will be combined to produce a sampling rate of 240 Hz. The lasers will follow separate parallel beam paths to the MAST vessel. Scattered light will b…
PublishedM. J. Walsh P. G. Carolan A. C. Darke M. R. Dunstan M. J. Forrest R. B. Huxford R. O’Gorman K. Pechstedt S. L. Prunty R. Scannell
Both ruby laser ( 300 points ) and NdYAG laser ( 19 points ) Thomson scattering systems are used on MAST. Fast nonlinear optical switching shunts laser beams from the four 50 Hz NdYAG lasers to obtain coaxial plasma illumination. The technique allows for future expandability to many laser systems. The ruby laser system is used in parallel. A broadb…
PublishedP. G. Carolan A. Patel N. J. Conway R. J. Akers C. A. Bunting G. F. Counsell J. Dowling M. R. Dunstan A. Kirk F. Lott M. N. Price M. R. Tournianski M. J. Walsh The Mast Team
The Mega Amp Spherical Torus ( MAST ) diagnostic needs are strongly influenced by physics goals that often require diagnostic integration and cross-mapping, especially in fine-scale investigations, such as transport barriers. Conversely, the unrivalled viewing access to the edge, scrape-off layer ( SOL ) and divertor regions, provided by the MAST o…
PublishedM. J. Walsh E. R. Arends P. G. Carolan M. R. Dunstan M. J. Forrest et al.
A dual laser Thomson scattering system is implemented in the Mega Amp Spherical Tokamak (MAST). The complementary features of each approach are exploited. One system is ideally suited to measuring detailed profile behavior across the plasma while the other is ideally suited though not exclusively to studying fast changing events and general charact…
Published