Journals

Showing 241 - 250 of 1605 Journals Results
2019
UKAEA-CCFE-PR(19)33

All density profile reconstruction techniques for both O-mode and X-mode are based on the assumption that the cut-off frequency profile is monotonic. However, there are many sources of perturbations to the plasma that generate hollow areas in the cut-off frequency profile, breaking the aforementioned assumption and causing a significant immediate r…

Preprint
2019
UKAEA-CCFE-PR(19)32

The novel technique of dynamical mode decomposition (DMD) is applied to the outputs of a numerical simulation of Kelvin-Helmholtz turbulence in a cylindical plasma, so as to capture and quantify the time evolution of the dominant nonlinear structures. These structures comprise rotationally symmetric deformations together with spiral patterns, which…

Preprint Published
2020
UKAEA-CCFE-PR(19)31

Tungsten, a plasma-facing material for future fusion reactors, may be exposed to air during abnormal operation or accidents. Only limited information is available on the evolution of related oxide phases. This work addresses the effect of substrate orientation on structural variations of tungsten oxides. Annealing experiments in an argon-oxygen atm…

Preprint Purchase
The published version of this paper is currently under embargo and will be available on 13/09/2021
2019
UKAEA-CCFE-PR(19)30

Alfven eigenmodes driven by energetic particles are routinely observed in tokamak plasmas. These modes consist of poloidal harmonics of shear Alfven waves coupled by inhomogeneity in the magnetic field. Further coupling is introduced by 3D inhomogeneities in the ion density during the assimilation of injected pellets. This additional coupling modi…

Preprint Published
2019
UKAEA-CCFE-PR(19)29

Two high purity tungsten powders, produced via different manufacturing techniques, were characterized to determine size distribution, morphology, thermal properties and flow characteristics and thus, the likely suitability for Laser Powder Bed Fusion (LPBF) production. Specimens from duplicate builds were produced with the two powders and character…

Preprint Published
2019
UKAEA-CCFE-PR(19)28

We study the amplitude modulation of the radial electric field constructed from the  Langmuir probe plasma potential measurements at the edge of MAST. The Empirical Mode Decomposition technique is applied, which allows us to construct fluctuations on temporal scales of plasma turbulence, the Geodesic Acoustic Mode and these associated with the res…

Preprint Published
2019
UKAEA-CCFE-PR(19)27

This report covers the initial progress on the development of material property handbook (MPH) of baseline CuCrZr, within the Materials Engineering Data and Design Integration (MAT-EDDI) of EUROfusion Material Database and Handbook group. Initial drafting of the baseline CuCrZr MPH structure is presented, with inclusion of available data, figures a…

Preprint Purchase
The published version of this paper is currently under embargo and will be available on 01/07/2021
2019
UKAEA-CCFE-PR(19)26

Guidelines are presented for the recommended method of assessing by analysis the structural integrity of divertor plasma facing components (PFCs) under high heat flux (HHF) loads. The objective is to enable analysis to provide greater supporting evidence for PFC qualification (which for ITER is currently achieved by test alone) and to provide reaso…

Preprint Purchase
The published version of this paper is currently under embargo and will be available on 21/06/2021
2019
UKAEA-CCFE-PR(19)25

Deuterium pellets are injected into initially pure hydrogen H-mode plasma in order to control H:D isotope mixture. The pellets are deposited in outer 20% of minor radius, similar to that expected in ITER creating transiently hollow electron density profiles. The isotope mixture of H:D ~ 45:55% is obtained in the core with pellet fuelling throughput…

Preprint Published
2019
UKAEA-CCFE-PR(19)24

Ion cyclotron emission (ICE) is detected from all large toroidal magnetically conned fusion (MCF) plasmas. It is a form of spontaneous suprathermal radiation, whose spectral peak frequencies correspond to sequential cyclotron harmonics of energetic ion species, evaluated at the emission location. We first present an account of the worldwide exper…

Preprint Published