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2014
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…
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2014
The technology implications of potential FWCD systems have been assessed at two frequencies of relevance to DEMO as part of a wider study of heating and current drive systems for the EFDA Power Plant Physics and Technology (PPP&T), based upon two reference DEMO designs. Using the results of Van Eester et al [1], systems studies carried out for a 62…
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2014
Numerical simulations of L-mode turbulence in the Scrape-Off Layer (SOL) are used to construct power scaling laws for the characteristic decay lengths of the temperature, density and heat flux at the outer midplane. Most of the results obtained are in qualitative agreement with the experimental observations despite the known limitation of the model…
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2014
Defect microstructures formed in ion-irradiated metals, for example iron or tungsten, often exhibit patterns of spatially ordered nano-scale dislocation loops. We show that such ordered dislocation loop structures may form spontaneously as a result of Brownian motion of loops, biased by the angular-dependent elastic interaction between the loops. P…
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2014
The DEMO Active Maintenance Facility (AMF) would be used for the storage, handling and processing of In- Vessel Components (IVC) throughout their time on site, the only exception being the time that they are installed in the vessel. It is anticipated that all handling operations associated with used components will have to be carried out using remo…
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2014
The misalignment of field coils in tokamaks can lead to toroidal asymmetries in the magnetic field, which are known as intrinsic error fields. These error fields often lead to the formation of locked modes in the plasma, which limit the lowest density that is achievable. The intrinsic error fields on MAST have been determined by the direct measurem…
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2014
In order to preserve the integrity of large tokamaks such as ITER, the number of disruptions has to be limited. JET has operated previously with a low frequency of disruptions (i.e., disruption rate) of 3.4% [P. C. de Vries et al., Nucl. Fusion 51, 053018 (2011)]. The start of operations with the new full-metal ITER-like wall at JET showed a marked…
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2014
The difference between the guiding center phase-space Lagrangians derived in J. W. Burby et al. [Phys. Plasmas 20, 072105 (2013)] and F. I. Parra and I. Calvo [Plasma Phys. Controlled Fusion 53, 045001 (2011)] is due to a different definition of the guiding center coordinates. In this brief communication, the difference between the guiding center c…
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2014
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…
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CCFE-PR(17)162015
Recent JET-ILW [1,2] experiments reiterated the importance of tuning the plasma fuelling in order to optimize ion cyclotron resonance frequency (ICRF) heating in high power H-mode discharges. By fuelling the plasma from gas injection modules (GIMs) located in the midplane and on the top of the machine instead of adopting the more standardly used di…
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