E. Lerche D. Van Eester Y. Kazakov P. Jacquet I. Monakhov M. Goniche L. Colas F. Rimini K. Crombé R. Dumont V. Kiptily M. Santala JET Contributors
Heating single ion species plasmas with ICRF is a challenging task: Fundamental ion cyclotron heating (w = w ci ) suffers from the adverse polarization of the RF electric fields near the majority cyclotron resonance while second harmonic heating (w = 2w ci ) typically requires pre-heating of the plasma ions to become efficient. Recently, w = 2w ci …
Preprint PublishedK. K. Kirov A. Ekedahl J. Bernardo M. Goniche J. Mailloux
In this report key aspects of Lower Hybrid Current Drive (LHCD) operation at JET are presented. Amplitude and broadening of the Radio Frequency (RF) spectrum at about 3.7GHz and the frequency shift of the lower sideband were analyzed by means of new diagnostic utilizing RF spectra measurements. Dependencies on plasma density, LH power and the toroi…
Preprint PublishedS. A. Silburn J. R. Harrison J. Howard K. J. Gibson H. Meyer C. A. Michael R. M. Sharples
A new coherence imaging Doppler spectroscopy diagnostic has been deployed on the UK’s Mega Amp Spherical Tokamak for scrape-off-layer and divertor impurity flow measurements. The system has successfully obtained 2D images of C III, C II, and He II line-of-sight flows, in both the lower divertor and main scrape-off-layer. Flow imaging has been obt…
PublishedXujing Li Leonid E. Zakharov Vladimir V. Drozdov
The edge equilibrium code (EEC) described in this paper is developed for simulations of the near edge plasma using the finite element method. It solves the Grad-Shafranov equation in toroidal coordinate and uses adaptive grids aligned with magnetic field lines. Hermite finite elements are chosen for the numerical scheme. A fast Newton scheme which …
PublishedL. Carbajal R. O. Dendy S. C. Chapman J. W. S. Cook
The magnetoacoustic cyclotron instability (MCI) probably underlies observations of ion cyclotron emission (ICE) from energetic ion populations in tokamak plasmas, including fusion-born alpha-particles in JET and TFTR [Dendy et al., Nucl. Fusion 35, 1733 (1995)]. ICE is a potential diagnostic for lost alpha-particles in ITER; furthermore, the MCI is…
PublishedG. G. Plunk P. Helander P. Xanthopoulos J. W. Connor
We investigate the linear theory of the ion-temperature-gradient (ITG) mode, with the goal of developing a general understanding that may be applied to stellarators. We highlight the Wendelstein 7X (W7-X) device. Simple fluid and kinetic models that follow closely from existing literature are reviewed and two new first-principle models are presente…
PublishedF. Durodié P. Dumortier M. Vrancken A. Messiaen R. Bamber D. Hancock S. Huygen D. Lockley F. Louche R. Maggiora D. Milanesio M. P. S. Nightingale M. Shannon P. Tigwell M. Van Schoor M. Vervier D. Wilson K. Winkler Cycle Team
ITER’s Ion Cyclotron Range of Frequencies (ICRF) system [Lamalle et al., Fusion Eng. Des. 88, 517–520 (2013)] comprises two antenna launchers designed by CYCLE (a consortium of European associations listed in the author affiliations above) on behalf of ITER Organisation (IO), each inserted as a Port Plug (PP) into one of ITER’s Vacuum Vessel …
PublishedP. C. De Vries M. Baruzzo G. M. D. Hogeweij S. Jachmich E. Joffrin P. J. Lomas G. F. Matthews A. Murari I. Nunes T. Pütterich C. Reux J. Vega JET-EFDA Contributors
In order to preserve the integrity of large tokamaks such as ITER, the number of disruptions has to be limited. JET has operated previously with a low frequency of disruptions (i.e., disruption rate) of 3.4% [P. C. de Vries et al., Nucl. Fusion 51, 053018 (2011)]. The start of operations with the new full-metal ITER-like wall at JET showed a marked…
PublishedA.J. Thornton A. Kirk J.R. Harrison P. Cahyna I.T. Chapman E. Nardon The Mast Team
The high pressure gradients in the edge of a tokamak plasma can lead to the formation of explosive plasma instabilities known as edge localised modes (ELMs). The control of ELMs is an important requirement for the next generation of fusion devices such as ITER. Experiments performed on the Mega Amp Spherical Tokamak (MAST) at Culham have shown that…
PublishedYueqiang Liu A. Kirk A.J. Thornton Mast Team
Optimal correction of the intrinsic error field (EF) by the correction coils in MAST is numerically studied, based on linear, full MHD plasma response computed in full toroidal geometry. Various optimisation criteria are proposed, and the results are compared with empirical optima from representative error field correction (EFC) experiments. The tw…
Published