UKAEA Papers

Showing 1 - 10 of 11 UKAEA Paper Results
2021
UKAEA-CCFE-CP(21)05

Plasma Event TRiggering for Alarms (PETRA) is a flexible new system at JET for detecting plasma events to trigger exception handling responses. It provides a platform for all existing and new techniques which involve processing JET real-time data to identify when to change the trajectory of a plasma shot, and reduces the technical cost and risk in …

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The published version of this paper is currently under embargo and will be available on 02/03/2023
2021
UKAEA-CCFE-PR(21)67

Using the PION ICRH modelling code on JET tokamak pulses, the effect of including pitch angle dependence within the RF diffusion operator is investigated. This is found to be of greatest importance to the particle distribution function in cases of higher harmonic heating and lower heating ion mass, resulting in faster drop-off of the distribution 

Preprint Published
2021
UKAEA-CCFE-PR(21)44

A model is presented for space charge neutralisation of positive ion beams. The model is used for the particular case of the beams used for magnetic based fusion applications. The beams consist, after a gas neutraliser, of ions and atoms at different energies. Account is taken of the co…

Preprint Published
2020
UKAEA-CCFE-CP(20)97

Since 2010, an in-vessel calibration light source (ICLS) has been used periodically on JET to calibrate a range of diagnostics at UV, visible and IR wavelengths. During shutdowns, the ICLS (essentially an integrating sphere) is positioned within the vacuum vessel by the remote handling (RH) system. Following the 2013 run, several changes were made …

Preprint Published
2018
UKAEA-CCFE-CP(20)81

The AlfvĂ©n Eigenmode Active Diagnostic system (AEAD) has undergone a major upgrade and redesign to provide a state of the art excitation and real-time detection system for JET. The new system consists of individual 4kW amplifiers for each of the six antennas, allowing for increased current, separate excitation and real time control of relative …

Preprint 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-CP(19)57

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. This causes a significant immediate …

Preprint Published
2019
UKAEA-CCFE-CP(19)30

The JET Real-Time Protection Sequencer (RTPS) co-ordinates responses for magnetic and kinetic actuators to protect the ITER-Like Wall from possible melting events and other undesirable scenarios. It allows programmable stop responses per pulse, based on alarms raised by other systems. The architecture combines a modular run-time application deve…

Preprint Published
2019
UKAEA-CCFE-CP(19)08

Charge-exchange spectroscopy on JET has become particularly challenging with the introduction of the ITER-like wall. The impurity spectra are weaker and contaminated by many tungsten lines. We have therefore upgraded the instrumentation to allow the simultaneous measurement of impurity and fuel-ion charge exchange by splitting the light between two…

Preprint Published
2019
UKAEA-CCFE-CP(19)06

The next D-T campaign will push JET ITER-like Wall (IWL) to high divertor power and energy levels. During the 2016 campaign, the Strike Point (SP) sweeping permitted relevant H-mode scenarios without exceeding the temperature limits imposed by JET Operation Instructions (JOIs). In the subsequent shutdown, six outer divertor tungsten-coated 2D carbo…

Preprint Published