G. De Temmerman M.Bacharis J.Dowling S.Lisgo
In this contribution, we report on experiments performed in MAST to investigate dust creation, transport and influence on plasma performance. The exceptional diagnostic access of MAST allows stereoscopic imaging of dust particles motion in both the divertor and the main chamber, utilising fast infrared cameras. This technique allows the 3D trajecto…
PublishedJ.M. Dewhurst B. Hnat R.O. Dendy
The effect of finite Larmor radius on the transport of passive charged test particles moving in turbulent electrostatic fields is investigated. The turbulent field is governed by a flexible model which is able to produce turbulence where zonal flows are damped or free to self-generate. A subtle interplay between trapping in small scale vortices and…
PublishedM. Cecconello M. Turnyanskiy S. Conroy G. Ericsson E. Ronchi S. Sangaroon R. Akers I. Fitzgerald A. Cullen M. Weiszflog
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 …
PublishedSteven P. Fitzgerald
Frank-Read sources are among the most important mechanisms of dislocation multiplication, and their operation signals the onset of yield in crystals. We show that the critical stress required to initiate dislocation production falls dramatically at high elastic anisotropy, irrespective of the mean shear modulus. We hence predict the yield stress of…
PublishedM-D Hua IT Chapman AR Field RJ Hastie SD Pinches The Mast Team
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…
PublishedM. Sasao L. Bertalot M. Ishikawa S. Popovichev
Accuracy of 10% is demanded to the absolute fusion measurement on ITER. To achieve this accuracy, a functional combination of several types of neutron measurement subsystem, cross calibration among them, and in situ calibration are needed. Neutron transport calculation shows the suitable calibration source is a DT/DD neutron generator of source str…
PublishedJakub Urban Michal Stránsky Vladimíir Fuchs Irina Voitsekhovitch Martin Valovic
The COMPASS tokamak, a mid-sized flexible device with ITER-like shape, which can operate in H-mode, is starting its re-established operation at the Institute of Plasma Physics in Prague. A new 600 kW, 40 keV neutral beam injection (NBI) system is foreseen as a major upgrade. Reported here are predictive simulations with the ASTRA transport code, in…
PublishedP. Bohm,
A new Thomson scattering diagnostic has been designed and is currently being installed on the COMPASS tokamak in IPP Prague in the Czech Republic. The requirements for this system are very stringent with approximately 3 mm spatial resolution at the plasma edge. A critical part of this diagnostic is the laser source. To achieve the specified paramet…
PublishedS P Fitzgerald S Aubry
A dislocation segment in a crystal experiences a “self force,” by virtue of the orientation-dependence of its elastic energy. If the crystal is elastically isotropic, this force is manifested as a couple acting to rotate the segment toward the lower energy of the pure screw orientation (i.e. acting to align the dislocation line with its Burgers…
Published