UKAEA Journals

Showing 1 - 7 of 7 Journals Results
2021
UKAEA-CCFE-PR(21)21

In this work, we use reduced and perturbative models to examine the stability of TAEs during the ITB afterglow in JET experiments designed for the observation of alpha driven TAEs.  We demonstrate that in JET-like conditions, it is sufficient to use an incompressible cold plasma model for the TAE to reproduce the experimental adiabatic features su…

Preprint
2016
CCFE-PR(16)12

We use the HAGIS code to compute the nonlinear stability of the Q=10 ITER baseline scenario to toroidal Alfveneigenmodes (TAE) and the subsequent effects of these modes on fusion alpha-particle redistribution. Our calculations build upon an earlier linear stability survey [Rodrigues, P. et al. (2015). Nuclear Fusion, 55(8), 083003] which provides a…

Preprint Published
2013

Remarkable progress has been made in diagnosing energetic particle instabilities on present-day machines and in establishing a theoretical framework for describing them. This overview describes the much improved diagnostics of Alfven instabilities and modelling tools developed world-wide, and discusses progress in interpreting the observed phenomen…

Published
2006

We present a study performed in ASDEX Upgrade H mode regime based on results from the broadband FM-CW reflectometry diagnostic, equipped with the unique capability of measuring the plasma density profile both at the low and high field sides of the tokamak. The plasma edge dynamics due to fast events such as the Edge Localized Modes (ELMs) is analyz…

Published
2004

A microwave interferometry technique is applied for the first time for detecting a discrete spectrum of Alfvén cascade (AC) eigenmodes excited with fast ions in reversed magnetic shear plasmas of the Joint European Torus. The interferometry measurements of plasma density perturbations associated with ACs show an unprecedented frequency and time re…

Published
2002

Experiments designed for generating internal transport barriers in the plasmas of the Joint European Torus [JET, P. H. Rebut et al. , Proceedings of the 10th International Conference, Plasma Physics and Controlled Nuclear Fusion, London ~ International Atomic Energy Agency, Vienna, (1985), Vol. I, p. 11 ] reveal cascades of Alfven perturbations wit…

Published
2001

Alfvén spectra in a reversed-shear tokamak plasma with a population of energetic ions exhibit a quasiperiodic pattern of primarily upward frequency sweeping (Alfvén cascade). Presented here is an explanation for such asymmetric sweeping behavior which involves finding a new energetic particle mode localized around the point of zero magnetic shear…

Published