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CCFE-PR(15)852015
An unstable branch of energetic geodesic acoustic mode (EGAM) is found using the fluid theory with fast ions characterised by their narrow width in energy distribution and collective transit along field lines. This mode, with a frequency much lower than the thermal GAM frequency !GAM, is now confirmed as a new type of unstable EGAM : a reactive in…
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CCFE-PR(15)892015
The interplay between toroidal rotation u, parallel flow shear u? and perpendicular flow shear ?E in the stabilisation of tokamak turbulence is investigated in non-linear flux-tube gyrokinetic simulations with the GKW code. The non-linear simulations are performed for a reference L-mode DIII-D plasma (the so-called shortfall case) at r/a = 0.8, var…
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CCFE-PR(15)882015
Verification is the fundamental step that any turbulence simulation code has to be submitted in order to assess the proper implementation of the underlying equations. We have carried out a cross comparison of three flux tube gyrokinetic codes, GENE [F. Jenko et al., Phys. Plasmas 7, 1904 (2000)], GKW [A. G. Peeters et al., Comput. Phys. Commun. 180…
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CCFE-PR(15)692015
Ions accelerated by electric fields (so-called runaway ions) in plasmas may explain observations in solar flares and fusion experiments, however limitations of previous analytic work have prevented definite conclusions. In this work we describe a numerical solver of the 2D non-relativistic linearized Fokker-Planck equation for ions. It solves the i…
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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)242015
Extensive neutronics and 3-D activation simulations were carried out to assess the levels of radiation throughout the ITER tokamak complex. The simulated radiation sources included DT fusion neutrons exiting the cryostat and gamma rays arising from the activation of cooling water, activated pipe chases and cask transfers. Resultant biological dos…
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CCFE-PR(15)492015
Dust re-suspension as a consequences of LOVA (Loss Of Vacuum Accident) or LOCA (Loss Of Coolant Accident) situations inside a nuclear fusion plant (ITER-like) is an important issue for the workers’ safety and for the security of the plant. The dust size expected inside tokamaks like ITER is of the order of microns (0.1-1000 m m). Analysis of the …
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CCFE-PR(15)372015
Ion cyclotron emission (ICE) was the first collective radiative instability, driven by confined fusion-born ions, observed from deuterium-tritium plasmas in JET and TFTR. ICE comprises strongly suprathermal emission, which has spectral peaks at multiple ion cyclotron harmonic frequencies as evaluated at the outer mid-plane edge of tokamak plasmas. …
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CCFE-PR(15)512015
Drift-reduced plasma fluid models are commonly used in plasma physics for analytic studies and simulations, so the validity of such models must be verified for the regions of parameter space in which tokamak plasmas exist. By deriving and comparing the linear dispersion relations for the drift-wave instability for both a drift-reduced model and a f…
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CCFE-PR(15)472015
The effects of resonant magnetic perturbations (RMPs) on the confinement of energetic (neutral beam) ions in the Mega Amp Spherical Tokamak (MAST) are assessed experimentally using measurements of neutrons, fusion protons and fast ion D _ (FIDA) light emission. In single null-diverted (SND) MAST pulses with relatively low plasma current (400 kA), t…
Showing 211 - 220 of 530 UKAEA Paper Results