Journals

Showing 1 - 10 of 18 Journals Results
2020
UKAEA-CCFE-PR(20)93

Parametric dependencies of the linear stability of toroidal Alfv´en eigenmode (TAE) in the presence of neutral beam injection (NBI) are investigated to understand the beam drive and damping effect of TAEs in JET and KSTAR. It is found that the results depend on the drift orbit width of the beam-ions normalized to the characteristic mode widths. In…

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The published version of this paper is currently under embargo and will be available on 28/04/2021
2019
UKAEA-CCFE-PR(20)67

Disruption prediction and avoidance is a critical need for next-step tokamaks such as ITER. The Disruption Event Characterization and Forecasting Code (DECAF) is used to fully automate analysis of tokamak data to determine chains of events that lead to disruptions and to forecast their evolution allowing sufficient time for mitigation or full av…

Preprint
2020
UKAEA-CCFE-PR(19)10

This paper outlines an approach towards improved rigour in tokamak turbulence transport model validation within integrated modelling. Gaussian process regression (GPR) techniques were applied for profile fitting during the preparation of integrated modelling simulations.  This allows for rigourous sensitivity tests of prescribed initial and bounda…

Preprint Published
2020
UKAEA-CCFE-PR(19)08

Intense bursts of suprathermal radiation, with spectral peaks at frequencies corresponding to the deuteron cyclotron frequency in the outer midplane edge region, are often detected from deuterium plasmas in the KSTAR tokamak that are heated by tangential neutral beam injection (NBI) of deuterons at 100 keV. Identifying th…

Preprint Published
2019
UKAEA-CCFE-PR(19)21

The JET exploitation plan foresees D-T operations in 2020 (DTE2). With respect to the first D-T campaign in 1997 (DTE1), when JET was equipped with a carbon wall, the experiments will be conducted in presence of a beryllium-tungsten ITER-like wall (ILW) and will benefit from an extended and improved set of diagnostics and higher additional heating …

Preprint Published
2018
UKAEA-CCFE-PR(18)11

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 …

Preprint Published
2017
CCFE-PR(17)12

This paper presents for the first time a statistical validation of predictive TRANSP simulations of plasma temperature using two transport models, GLF23 and TGLF, over a database of 80 baseline H-mode discharges in JET-ILW. While the accuracy of the predicted Te with TRANSP-GLF23 is affected by plasma collisionality, the dependency of predictions o…

Preprint Published
2017
CCFE-PR(17)04

Ion cyclotron emission (ICE) is detected during edge localised modes (ELMs) in the KSTAR tokamak at harmonics of the proton cyclotron frequency in the outer plasma edge. The emission typically chirps downward (occasionally upward) during ELM crashes, and is driven by confined 3MeV fusion-born protons that have large drift excursions from the plasma…

Preprint Published
2015
CCFE-PR(15)46

A consistent deterioration of global confinement in H-mode experiments has been observed in JET [1] following the replacement of all carbon Plasma Facing Components (PFCs) with an all metal (‘ITER-like’) wall (ILW). This has been correlated to the observed degradation of the pedestal confinement, as lower electron temperature (T e ) values are …

Preprint Published
2014

It is shown that rapid substantial changes in heating rate can induce transitions to improved energy confinement regimes in zero-dimensional models for tokamak plasma phenomenology. We examine for the first time the effect of step changes in heating rate in the models of Kim and Diamond [Phys. Rev. Lett. 90, 185006 (2003)] and Malkov and Diamond [P…

Published