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2010
A motional Stark effect MSE diagnostic is now installed and operating routinely on the MAST spherical tokamak, with 35 radial channels, spatial resolution of 2.5 cm, and time resolution of 1 ms at angular noise levels of 0.5°. Conventional albeit very narrow interference filters isolate or polarized emission. Avalanche photodiode detectors with di…
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2010
The beam emission spectroscopy BES turbulence diagnostic on MAST is to be upgraded in June 2010 from a one-dimensional trial system to a two-dimensional imaging system 8 radial 4 poloidal channels based on a newly developed avalanche photodiode array camera. The spatial resolution of the new system is calculated in terms of the point spread functio…
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2010
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…
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2010
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. …
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2010
A prototype neutron camera has been developed and installed at MAST as part of a feasibility study for a multichord neutron camera system with the aim to measure the spatial and time resolved 2.45 MeV neutron emissivity profile. Liquid scintillators coupled to a fast digitizer are used for neutron/ gamma ray digital pulse shape discrimination. The …
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2010
An avalanche photodiode based APD detector for the visible wavelength range was developed for low light level, high frequency beam emission spectroscopy BES experiments in fusion plasmas. This solid state detector has higher quantum efficiency than photomultiplier tubes, and unlike normal photodiodes, it has internal gain. This paper describes the …
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2010
A long wavelength range infrared camera (LWIR) has been installed on MAST to compliment the existing medium wave infrared system. Simultaneous LWIR/MWIR temperature measurements have been made in the lower and upper divertors of MAST. As expected, the LWIR system is less sensitive to disturbances from hot spots on the surface. A thorough correction…
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2010
The impact of Resonant Magnetic Perturbations (RMPs) on the edge of MAST L-mode plasmas is studied using a mid-plane reciprocating probe equipped with a Gundestrup probe head. A strong impact on the characteristics of the ion saturation current fluctuations is observed just inside the separatrix, with a broadening of the power spectrum and an asymm…
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2010
The retention of deuterium fuel during MAST discharges has been studied using the method of global gas balance. The results show that with inter-shot 4 He- GDC, the total number of particles retained for a discharge increases with total number of injected particles, and the total retention fraction stays very high, mostly around 80%, and can be alm…
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2010
Plasma rotation in tokamaks is of special interest for its potential stabilising effect on micro- and macro instabilities, leading to increased confinement. In MAST, the torque from Neutral Beam Injection (NBI) can spin the plasma to a core velocity ~ 300km.s -1 (Alfven Mach number ~ 0.3). Low density plasmas often exhibit a weakly non-monotonic sa…
Showing 241 - 250 of 309 UKAEA Paper Results