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CCFE-PR(17)622017
Recently we have presented direct experimental evidence for large defect clusters being formed in primary damage cascades in self-ion irradiated tungsten [Yi et al., EPL 110:36001 (2015)]. This large size is significant, as it implies th…
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CCFE-PR(17)502017
The interaction of L-mode and inter-ELM Scrape-Off Layer (SOL) filaments is investigated by simulating the dynamics of two seeded density perturbations with different initial separation. A numerical campaign of 2D and 3D simulations is presented to explore the effect that different filaments' perpendicular size and relative distance have on their r…
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CCFE-PR(17)452017
Helium bubble production in tungsten has been studied combining transmission electron microscopy and in situ irradiations with 10 keV He+ ions. The irradiations were carried out at four temperatures (773 K, 1073 K, 1273 K, 1473 K), and were held at intervals of (0.45; 0.9; 1.2; 1.5) × 1020 He+/m2 for each temperature. Based on detailed analyses of…
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CCFE-PR(16)622016
Spherical tokamaks (STs) typically have lower magnetic fields than conventional tokamaks, but similar mass densities. Suprathermal ions with relatively modest energies, in particular beam-injected ions, consequently have speeds close to or exceeding the Alfven velocity, and can therefore excite a range of Alfvenic instabilities. STs heated with neu…
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CCFE-PR(16)452016
It is shown that ITG turbulence close to the threshold exhibits a long time behaviour, with smaller heat fluxes at later times. This reduction is connected with the slow growth of long wave length zonal flows and, consequently, the numerical dissipation on these flows must be sufficient small. Close to the nonlinear threshold for turbulence generat…
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CCFE-PR(16)502016
We develop a gyrokinetic treatment for ions in the magnetic presheath, close to the plasma-wall boundary. We focus on magnetic presheaths with a small magnetic field to wall angle, a << 1 (in radians). Characteristic lengths perpendicular to the wall in such a magnetic presheath scale with the typical ion Larmor orbit size, r
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CCFE-PR(16)062016
Experiments have been performed under the coordination of the International Tokamak Physics Activity (ITPA) on several tokamaks, including ASDEX Upgrade (AUG), JET and DIII-D, to characterize the increased ICRF antenna loading achieved by optimizing the position of gas injection relative to the RF antennas. On DIII-D, AUG and JET (with the ITER-Lik…
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CCFE-PR(15)652015
Recently the LHCb collaboration has released a series of papers [1] [2] [3] [4] [5] [6] on Bd or Bs decays to J/ +X where X is a scalar or axial vector meson. This mechanism gives a potentially clean flavour filtering. Production in Bs ? J/ + X(s¯s) occurs at leading order and the Bd ? J/ + X(d ¯ d) is the dominant entree to the accompanying m…
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CCFE-PR(15)672015
Preferential ion heating in the solar wind, observed as the occurrence of an ion beam which drifts along the background magnetic field with a velocity close to the local Alfven speed, is still an open problem. Several mechanisms have been identified that might work together in the solar wind to drive the observed ion heating. These mechanisms resul…
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CCFE-PR(17)392015
In normal operation the JET neutral beam injectors have the operating gas supplied to the ion source and the neutraliser. For tritium operation the gas is supplied to both the ion source and neutraliser at a point close to the earth grid (grid gas) due to the difficulty in producing a gas line with a secondary containment and a ceramic break fo…
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