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CCFE-PR(17)192016
An explanation of the observed improvement in H-mode pedestal characteristics with increasing core plasma pressure or poloidal beta, pol b , as observed in MAST and JET, is sought in terms of the impact of the Shafranov shift, D¢ , on ideal ballooning MHD stability. To illustrate this succinctly, a self-consistent treatment of the low magnetic she…
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CCFE-PR(16)302016
In future nuclear fusion reactors high heat load events, such as edge-localised modes (ELMs), can potentially damage divertor materials and release impurities into the main plasma, limiting plasma performance. The most difficult to handle are type I ELMs since they carry the largest fraction of energy from the plasma and therefore deposit the large…
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CCFE-PR(15)1012015
Tokamaks are traditionally viewed as axisymmetric devices. However this is not always true, for example in the presence of saturated instabilities, error fields, or resonant magnetic perturbations (RMPs) applied for edge localized mode (ELM) control. We use the VMEC code (Hirshman and Whitson 1983 Phys. Fluids 26 3553) to …
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CCFE-PR(15)722015
The Synthetic Aperture Microwave Imaging (SAMI) diagnostic has conducted proof-of-principle 2D Doppler backscattering (DBS) experiments on MAST. SAMI actively probes the plasma edge using a wide ( 40° vertical and horizontal) and tuneable (10-35.5 GHz) beam. The Doppler backscattered signal is digitised in vector form using an array of eight Vival…
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CCFE-PR(15)702015
This paper presents a numerical investigation of isolated filament dynamics in a simulation geometry representative of the scrape-off layer (SOL) of the Mega Amp Spherical Tokamak (MAST) previously studied in [N.R.Walkden et.al, Plasma Phys. Control. Fusion, 55 (2013) 105005]. This paper focuses on the evolution of filament cross-sections at the ou…
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CCFE-PR(15)712015
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…
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CCFE-PR(17)292015
The design of a divertor target for DEMO remains one of the most challenging engineering tasks to be overcome on the path to fusion power. Under the European DEMO programme, a promising concept known as Thermal Break has been developed at CCFE. This concept is a variation of the ITER tungsten divertor in which the pure Copper interlayer between Cop…
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CCFE-PR(17)262015
For the initial phase of MAST-U operation the two existing neutral beam injection systems will be used, but must be substantially upgraded to fulfil expected operational requirements. The major elements are the design, manufacture and installation of a bespoke bending magnet and Residual Ion Dump (RID) system. The MAST-design full energy dump is b…
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CCFE-PR(15)1172015
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…
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CCFE-PR(15)532015
Filamentary transport across the scrape off layer is a key issue for the design and operation of future devices, such as ITER, DEMO and MAST-U, as it sets the power loadings to the divertor and first wall of the machine. Analysis has been performed on L mode filaments in MAST in order to gain an understanding of the spatial structure and attempt to…
Showing 121 - 130 of 302 UKAEA Paper Results