Showing 1 - 10 of 48 Journals Results
2020
UKAEA-CCFE-PR(20)131
R.A. Tinguely P.G. Puglia N. Fil S. Dowson M. Porkolab A. Dvornova A. Fasoli M. Fitzgerald G.T.A. Huysmans M. Maslov S. Sharapov D. Testa JET Contributors
This paper presents a dedicated study of plasma-antenna (PA) coupling with the Alfvén Eigenmode Active Diagnostic (AEAD) in JET. Stable AEs and their resonant frequencies f, damping rates < 0, and toroidal mode numbers n are measured for various PA separations and limiter versus X-point magnetic con gurations. Two stable AEs are observed to …
Preprint2020
UKAEA-CCFE-PR(20)100
V.G. Kiptily M. Fitzgerald Ye.O. Kazakov M. Nocente J. Ongena S.E. Sharapov M. Dreval Ž. Štancar T. Craciunescu J. Garcia L. Giacomelli V.Goloborodko J. Oliver H. Weisen
Dedicated experiments to generate high-energy D ions and D-3He fusion-born alpha particles have been performed at the Joint European Torus (JET) with the ITER-like wall (ILW). Deuterium ions from neutral beam injection (NBI) with acceleration voltage of 100 keV were accelerated to higher energies in the core of mixed D-3He pl…
Preprint2020
UKAEA-CCFE-PR(20)93
Jaemin Seo J. Kim J. Mailloux R.J. Dumont M. Fitzgerald S.E. Sharapov D.L. Keeling F. Koechl F.J. Casson C.Y. Lee T.S. Hahm Y.-S. Na JET contributors
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…
Preprint Purchase2020
UKAEA-CCFE-PR(20)75
V. Aslanyan S. Taimourzadeh L. Shi Z. Lin G. Dong P. Puglia M. Porkolab R. Dumont S. E. Sharapov J. Mailloux M. Tsalas M. Maslov A. Whitehead R. Scannell S. Gerasimov S. Dorling S. Dowson H. K. Sheikh T. Blackman G. Jones A. Goodyear K. K. Kirov P. Blanchard A. Fasoli D. Testa JET Contributors
The Gyrokinetic Toroidal Code (GTC) has been used to study Toroidal Alfven Eigenmodes (TAEs) in high- performance plasmas. Experiments performed at the Joint European Torus, where TAEs were driven by energetic particles arising from Neutral Beams, ion cyclotron resonant heating and resonantly excited by ded…
Preprint Published2020
UKAEA-CCFE-PR(19)05
M. Fitzgerald J. Buchanan R.J. Akers B.N. Breizman S.E. Sharapov
HALO (HAgis LOcust) solves the initial value Vlasov-Maxwell problem perturbatively for application to certain nonlinear wave-particle problems in tokamak plasmas. It uses the same basic approach as the HAGIS code (Pinches et al., 1998) for wave evolution but is built on the LOCUST-GPU full-orbit code (Akers et al., 2012) for the solution of the …
Preprint Purchase2019
UKAEA-CCFE-PR(19)65
Allah Rakha M.J. Mantsinen A.V. Melnikov S.E. Sharapov D.A. Spong A. Lopez-Fraguas F. Castejon
Alfven frequency sweeping modes in stellarator plasmas with normal and reversed shear rotational transform are modelled using a reduced MHD model. We focus on a TJ-II dynamic discharge in which a sequence of frequency sweeping modes with a frequency sweeping range from 20 kHz to 140 kHz (Melnikov A.V. et al 2014 Nucl. Fusion 54 123002) have been ob…
Preprint Published2019
UKAEA-CCFE-PR(19)60
A. Dvornova G.T.A. Huijsmans S. Sharapov F.J. Artola P. Puglia M. Hoelzl S. Pamela A. Fasoli D. Testa
Toroidal Alfven Eigenmode (TAE) excitation can be caused by fusion-born or Ion Cyclotron Resonance and neutral beam heating fast particles through wave-particle resonance. TAEs may affect fast particle confinement, reduce heating and current drive efficiency, cause damage to the first wall, and decrease overall plasma performance. Excitation of TA…
Preprint Published2019
UKAEA-CCFE-PR(19)30
H. J. C. Oliver S. E. Sharapov B. N. Breizman A. K. Fontanilla D. A. Spong D. Terranova JET Contributors
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 Published2019
UKAEA-CCFE-PR(19)21
Luca Garzotti C. Challis R. Dumont D. Frigione J. Graves E Lerche J. Mailloux M. Mantsinen F. Rimini F. Casson A. Czarnecka J. Eriksson R. Felton L. Frassinetti D. Gallart J. Garcia C. Giroud E. Joffrin H.-T. Kim N. Krawczyk M. Lennholm P. Lomas C. Lowry L. Meneses I. Nunes C. M. Roach M. Romanelli S. Sharapov S. Silburn A. Sips E. Stefanikova M. Tsalas D. Valcarcel M. Valovic JET contributors
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 Published2018
UKAEA-CCFE-PR(18)73