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UKAEA-CCFE-PR(18)702018
We report results of the benchmarking of core particle transport simulations by the codes widely used in the interpretative transport analyses and predictive modelling of tokamak plasmas. Our analysis includes formulation of transport equations, difference between electron and ion particle solvers, comparison of simulations of particle sinks and so…
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UKAEA-CCFE-PR(18)692018
The impact of the three-dimensional (3D) tokamak geometry from external magnetic perturbations (MPs) on the local edge stability has been examined in high confinement mode (H-mode) plasmas with edge localised modes (ELMs) in ASDEX Upgrade. The 3D geometry has been probed using rigidly rotating MP fields. The measured distortions of the plasma bound…
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UKAEA-CCFE-PR(18)582018
Using a kinetic model for the ions and adiabatic electrons, we solve a steady state, electron-repelling magnetic presheath in which a uniform magnetic field makes a small angle α
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UKAEA-CCFE-PR(19)022018
Following the lead of [Nguyen Van Yen Nucl. Fus. 52 (2012) 013005 (11pp)], this article tackles the problem of tomographic inversion with one camera assuming a constant emissivity of light along the magnetic field lines. In this way, the 3D problem reduces to 2D by helical symmetry, allowing for the reconstruction of any poloidal plane in the …
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UKAEA-CCFE-PR(18)452018
In magnetic fusion devices, unwanted non-axisymmetric magnetic eld perturbations, known as error fields (EF), can have detrimental effects on plasma stability and confinement. To minimize their impact on plasma performances and on the available operational space, it is important to identify the EF sources and develop EF control strategies. MAST Up…
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UKAEA-CCFE-PR(18)442018
High-Z impurities in magnetic confinement devices are prone to develop density variations on the fluux-surface, which can significantly affect their transport. In this paper, we generalize earlier analytic stellarator calculations of the neoclassical radial impurity flux in the mixed-collisionality regime (collisional impurity and low-collisionalit…
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UKAEA-CCFE-PR(18)372018
Ultrafast irradiation can drive the electrons in a material out of thermal equilibrium with the nuclei, producing hot, transient electronic states that modify the interatomic potential energy surface. We present, for the first time, a rigorous formulation of two-temperature molecular dynamics that can accommodate these electronic effects in the fo…
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UKAEA-CCFE-PR(18)342018
Tangentially viewing fast camera footage of the low-field side snowflake minus divertor in TCV is analysed across a four point scan in which the proximity of the two X-points is varied systematically. The apparent flow observed in the post-processed movie shows two distinct regions of the camera frame exhibiting differing flow patterns. One flow in…
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UKAEA-CCFE-PR(18)252018
The evolution of the defect microstructure in materials at high temperature is dominated by diffusion-mediated interactions between dislocations, vacancy clusters and surfaces. This gives rise to complex non-linear couplings between interstitial and vacancy-type dislocation loops, cavities and the field of diffusing vacancies that adiabatically fol…
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UKAEA-CCFE-PR(18)112018
Chirping observed in ion cyclotron emission (ICE) from the KSTAR tokamak at sequential proton harmonics in the range 200 to 500 MHz has recently been interpreted (B. Chapman et al., Nucl. Fusion 57, 124004 (2017)) as due to fast, sub-microsecond, evolution of the local deuterium plasma density. This density evolution changes the plasma environment …
Showing 161 - 170 of 507 UKAEA Paper Results