UKAEA Journals

Showing 1 - 10 of 29 Journals Results
2021
UKAEA-CCFE-PR(21)26

The first divertor was installed in the JET machine between 1992 and 1994 and was operated with carbon tiles and then beryllium tiles in 1994-5. Post-mortem studies after these first experiments demonstrated that most of the impurities deposited in the divertor originate in the main chamber, and that asymmetric deposition patterns generally favouri…

Preprint Published
2019

Data on erosion and melting of beryllium upper limiter tiles, so-called dump plates (DP), are presented for all three campaigns in the JET tokamak with the ITER-like wall. High-resolution images of the upper wall of JET show clear signs of flash melting on the ridge of the roof-shaped tiles. The melt layers move in the poloidal direction from the i…

Published
2018

The first divertor was installed in the JET machine between 1992 and 1994 and was operated with carbon tiles and then beryllium tiles in 1994–5. Post-mortem studies after these first experiments demonstrated that most of the impurities deposited in the divertor originate in the main chamber, and that asymmetric deposition patterns generally favou…

Published
2018
UKAEA-CCFE-PR(20)64

The JET outboard divertor targets are the in-vessel components which receive the largest heat flux density. Surface delamination, radial cracks, and tie rod failures have been observed in the outboard tungsten-coated CFC tiles, while bulk tungsten special lamellas were intentionally melted in dedicated experiments. These different types of damag…

Preprint
2019
UKAEA-CCFE-PR(19)62

The pedestal structure, ELM losses and linear MHD stability are analysed in a series of JET-ILW H and D type I ELMy H-mode plasmas. The pedestal pressure (pPED) is typically higher in D than in H at the same input power, with the difference mainly due to lower density in H than in D. At the same input power, the pedestal electron pressur…

Preprint Purchase
The published version of this paper is currently under embargo and will be available on 09/03/2022
2017
CCFE-PR(17)75

This paper presents the use of a novel modelling technique based around intermittent transport due to filament motion, to interpret experimental profile and fluctuation data in the scrape-off layer (SOL) of JET during the onset and evolution of a density profile shoulder. Three cases are studied at different points in a density ramp experiment wher…

Preprint Published
2017
CCFE-PR(17)03

Statistical analysis of the ion flux to the JET outer-wall is conducted in outer-wall limiter mounted Langmuir probe (OLP) time-series across a wide range of plasma current and line-averaged density during Ohmically heated horizontal target L-mode plasmas. The mean, _, and the standard deviation, _, of the ion-saturation current measured by the OLP…

Preprint Published
2016
CCFE-PR(16)78

The dynamics and stability of divertor detachment in N2 seeded, type-I, ELMy H-mode plasmas with dominant NBI heating in the JET-ILW device is studied by means of an integrated analysis of diagnostic data from several systems, classifying data relative to the ELM times. It is thereby possible to study the response of the detachment evolution to the…

Preprint Published
2016
CCFE-PR(16)24

Rotating collectors and quartz microbalances (QMBs) are used in JET to provide time-dependent measurements of erosion and deposition. Rotation of collector discs behind apertures allows recording of the long term evolution of deposition. QMBs measure mass change via the frequency deviations of vibrating quartz crystals. These diagnostics are used t…

Preprint Published
2016
CCFE-PR(16)23

JET components are removed periodically for surface analysis to assess material migration and fuel retention. This paper describes issues related to handling JET components and procedures for preparing samples for analysis; in particular a newly developed procedure for cutting beryllium tiles is presented. Consideration is also given to the hazards…

Preprint Published