2018
C Sozzi; E Alessi; A Pau; A Fanni; B Cannas; S Carcangiu; G Sias; P Sparapani; P J Lomas; S Gerasimov; F Koechl; F Rimini; I Voitsekhovitch; P McCullen; M Baruzzo; T Bolzonella; R Delogu; A Murari; M Bernert; O Kudlacek; M Maraschek; T C Blanken; C Cianfarani; F A A Felici; C Galperti; O Sauter; U Sheik; A Teplukhina; D Ferreira; M Gelfusa; M Lungaroni; E Peluso; I Ivanova-Stanik; E Joffrin; E. Lerche; S. Moradi; E Pawelec; G Ratta; J Vega; G Stankunas; JET Contributors; EUROfusion MST1 Team
Early Identification of Disruption Paths for Prevention and Avoidance Proceedings Article
In: Proceedings Fusion Energy 2018, pp. EX-P1/22, 2018.
@inproceedings{1885,
title = {Early Identification of Disruption Paths for Prevention and Avoidance},
author = {C Sozzi and E Alessi and A Pau and A Fanni and B Cannas and S Carcangiu and G Sias and P Sparapani and P J Lomas and S Gerasimov and F Koechl and F Rimini and I Voitsekhovitch and P McCullen and M Baruzzo and T Bolzonella and R Delogu and A Murari and M Bernert and O Kudlacek and M Maraschek and T C Blanken and C Cianfarani and F A A Felici and C Galperti and O Sauter and U Sheik and A Teplukhina and D Ferreira and M Gelfusa and M Lungaroni and E Peluso and I Ivanova-Stanik and E Joffrin and E. Lerche and S. Moradi and E Pawelec and G Ratta and J Vega and G Stankunas and JET Contributors and EUROfusion MST1 Team},
year = {2018},
date = {2018-10-01},
booktitle = {Proceedings Fusion Energy 2018},
volume = {IAEA-CN-258},
pages = {EX-P1/22},
abstract = {Disruption prevention in high performance, high current, long duration discharges requires a substantial evolution of the schemes applied in most of the present tokamaks. An efficient prevention scheme requires the early identification of the nature of the off-normal behaviour and the automatic selection of the appropriated countermeasure, either avoidance or mitigation. For the purpose of the avoidance, on which this paper is focused, the disruption can be seen as the result of the interplay of the physical events and of the control system responses to them and to the technical failures. The building blocks of such description should include the integration of several sets of plasma scalar data, plasma profile data, magneto- hydrodynamics (MHD) indicators and engineering data. Previous work has shown the potential of the Generative Topographic Mapping (GTM) algorithm for identification and discrimination of the disruptive operational space in tokamak devices. In the paper it is shown that the magnetic fluctuations associated with rotating MHD modes can be characterized using a set of observables derived from the Singular Value Decomposition applied to the data collected by an array of pick- up coils. They provide an input to the GTM analysis such that a clustering separating disruptive and non-disruptive timeslices can be found. A selection criterion is derived from this analysis such that a warning time of the order of seconds about the incoming disruption can be obtained.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
M. Tripsky
Fundamentals of Discharge Initiation by ICRF Antennas in Fusion Devices PhD Thesis
University of Ghent, 2018.
@phdthesis{1875,
title = {Fundamentals of Discharge Initiation by ICRF Antennas in Fusion Devices},
author = {M. Tripsky},
year = {2018},
date = {2018-10-01},
school = {University of Ghent},
series = {Thesis},
keywords = {},
pubstate = {published},
tppubtype = {phdthesis}
}
M Usoltceva; E Faudot; J Ledig; S Devaux; S Heuraux; G V Zadvitskiy; R Ochoukov; J Moritz; K. Crombé; J. -M. Noterdaeme
Theory of a cylindrical Langmuir probe parallel to the magnetic field and its calibration with interferometry Journal Article
In: Review of Scientific Instruments, vol. 89, pp. 10J124, 2018.
@article{1877,
title = {Theory of a cylindrical Langmuir probe parallel to the magnetic field and its calibration with interferometry},
author = {M Usoltceva and E Faudot and J Ledig and S Devaux and S Heuraux and G V Zadvitskiy and R Ochoukov and J Moritz and K. Crombé and J. -M. Noterdaeme},
year = {2018},
date = {2018-10-01},
journal = {Review of Scientific Instruments},
volume = {89},
pages = {10J124},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
G. Verdoolaege; S M Kaye; C Angioni; O J W F Kardaun; F Ryter; K Thomsen; M Maslov; M Romanelli; JET Contributors; ASDEX Upgrade Team; EUROfusion MST1 Team
First Analysis of the Updated ITPA Global H-mode Confinement Database Proceedings Article
In: Proceedings Fusion Energy 2018, pp. EX/P7-1, 2018.
@inproceedings{1887,
title = {First Analysis of the Updated ITPA Global H-mode Confinement Database},
author = {G. Verdoolaege and S M Kaye and C Angioni and O J W F Kardaun and F Ryter and K Thomsen and M Maslov and M Romanelli and JET Contributors and ASDEX Upgrade Team and EUROfusion MST1 Team},
year = {2018},
date = {2018-10-01},
booktitle = {Proceedings Fusion Energy 2018},
volume = {IAEA-FEC},
pages = {EX/P7-1},
abstract = {First results are presented of the ongoing analysis of the latest version of the ITPA global H-mode confinement database, following addition in 2017 of new data from JET with the ITER-like wall and ASDEX Upgrade with the full tungsten wall. The main characteristics of the data are presented and the regression methods are discussed that are used for estimation of the global energy confinement scaling in terms of engineering parameters. Employing a simple power law model for the scaling and several different methods, regression analysis has been performed of the latest version of the database and various constrained subsets. Initial results of the scaling analysis are presented and compared with the IPB98(y,2) scaling expression.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
T Wang; Mazonand D J Svensson; D Li; A Jardin; G. Verdoolaege
Incorporating magnetic equilibrium information in Gaussian process tomography for soft X-ray spectroscopy at WEST Proceedings Article
In: Review of Scientific Instruments, pp. 10F103, 2018.
@inproceedings{1874,
title = {Incorporating magnetic equilibrium information in Gaussian process tomography for soft X-ray spectroscopy at WEST},
author = {T Wang and Mazonand D J Svensson and D Li and A Jardin and G. Verdoolaege},
year = {2018},
date = {2018-10-01},
booktitle = {Review of Scientific Instruments},
volume = {89},
number = {10},
pages = {10F103},
abstract = {Gaussian process tomography (GPT) [J. Svensson, JET Internal Report EFDA-JET-PR(11)24, 2011 and D. Li, J. Svensson, H. Thomsen, F. Medina, A. Werner, and R. Wolf, Rev. Sci. Instrum. 84, 083506 (2013)] is a recently developed tomography method applied earlier to soft X-ray (SXR) spectroscopy on WEST—Tungsten (W) Environment in Steady-state Tokamak. The short execution time of the algorithm makes GPT an important candidate for providing real-time information on impurity transport and for fast MHD control. In earlier work, GPT has shown its flexibility by providing good reconstruction results without background information about the magnetic equilibrium. On the other hand, information about the magnetic flux surface geometry can in general be useful for additional regularization of the solution. In this paper, we develop a way to take into account the equilibrium information, by constructing a covariance matrix of the prior Gaussian process depending on the flux surface geometry. The GPT method is validated using synthetic SXR emissivity profiles relevant to WEST plasmas and compares favorably with the classical algorithm based on minimization of the Fisher information.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
H P Laqua; J Baldzuhn; H Braune; S Bozhenkov; K J Brunner; Y. O. Kazakov; S Marsen; D Moseev; T Stange; R C Wolf; M Zanini; W7-X team
Overview of W7-X ECRH Results in OP1.2a Proceedings Article
In: EPJ Web conferences, pp. 01011, 2018.
@inproceedings{1869,
title = {Overview of W7-X ECRH Results in OP1.2a},
author = {H P Laqua and J Baldzuhn and H Braune and S Bozhenkov and K J Brunner and Y. O. Kazakov and S Marsen and D Moseev and T Stange and R C Wolf and M Zanini and W7-X team},
year = {2018},
date = {2018-09-01},
booktitle = {EPJ Web conferences},
volume = {187},
pages = {01011},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
R J Dumont; J Mailloux; V Aslanyan; M Baruzzo; C D Challis; I Coffey; A Czarnecka; E Delabie; J Eriksson; J Faustin; J Ferreira; M Fitzgerald; J Garcia; L Giacomelli; C Giroud; N Hawkes; Ph. Jacquet; E Joffrin; T Johnson; D Keeling; D King; V Kiptily; B Lomanowski; E. Lerche; M Mantsinen; L Meneses; S Menmuir; K McClements; S. Moradi; F Nabais; M Nocente; A Patel; H Patten; P Puglia; R Scannell; S Sharapov; E R Solano; M Tsalas; P Vallejos; H Weisen; JET contributors
Scenario development for the observation of alpha-driven instabilities in JET DT plasmas Journal Article
In: Nuclear Fusion, vol. 58, no. 8, pp. 082005, 2018.
@article{1868,
title = {Scenario development for the observation of alpha-driven instabilities in JET DT plasmas},
author = {R J Dumont and J Mailloux and V Aslanyan and M Baruzzo and C D Challis and I Coffey and A Czarnecka and E Delabie and J Eriksson and J Faustin and J Ferreira and M Fitzgerald and J Garcia and L Giacomelli and C Giroud and N Hawkes and Ph. Jacquet and E Joffrin and T Johnson and D Keeling and D King and V Kiptily and B Lomanowski and E. Lerche and M Mantsinen and L Meneses and S Menmuir and K McClements and S. Moradi and F Nabais and M Nocente and A Patel and H Patten and P Puglia and R Scannell and S Sharapov and E R Solano and M Tsalas and P Vallejos and H Weisen and JET contributors},
url = {http://stacks.iop.org/0029-5515/58/i=8/a=082005},
year = {2018},
date = {2018-08-01},
journal = {Nuclear Fusion},
volume = {58},
number = {8},
pages = {082005},
abstract = {In DT plasmas, toroidal Alfvén eigenmodes (TAEs) can be made unstable by the alpha particles resulting from fusion reactions, and may induce a significant redistribution of fast ions. Recent experiments have been conducted in JET deuterium plasmas in order to prepare scenarios aimed at observing alpha-driven TAEs in a future JET DT campaign. Discharges at low density, large core temperatures associated with the presence of internal transport barriers and characterised by good energetic ion confinement have been performed. ICRH has been used in the hydrogen minority heating regime to probe the TAE stability. The consequent presence of MeV ions has resulted in the observation of TAEs in many instances. The impact of several key parameters on TAE stability could therefore be studied experimentally. Modeling taking into account NBI and ICRH fast ions shows good agreement with the measured neutron rates, and has allowed predictions for DT plasmas to be performed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
R Bilato; A R Polevoi; M Schneider; M Brambilla; E Fable; M Weiland; Y. O. Kazakov; E. Lerche; A Loarte; J. Ongena; S D Pinches; D. Van Eester
Synergies between H-NBI fast-ions and ICRF heating inthe non-acitivided oprational phase of ITER Proceedings Article
In: Europhysics Conference Abstracts, pp. P1.1070, 2018.
@inproceedings{1861,
title = {Synergies between H-NBI fast-ions and ICRF heating inthe non-acitivided oprational phase of ITER},
author = {R Bilato and A R Polevoi and M Schneider and M Brambilla and E Fable and M Weiland and Y. O. Kazakov and E. Lerche and A Loarte and J. Ongena and S D Pinches and D. Van Eester},
year = {2018},
date = {2018-07-01},
booktitle = {Europhysics Conference Abstracts},
volume = {42A},
pages = {P1.1070},
abstract = {45th EPS Conference on Plasma Physics, Prage (Czech Republic), 02 - 06 July 2018},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
I Borodkina; D Douai; D Alegre; D Borodin; S Brezinsek; E Cal; Y Corre; A Drenik; J Gaspar; E Joffrin; C C Klepper; T Loarer; M Maslov; G Sergienko; S Vartanian; T. Wauters; JET Contributors
Isotope wall content control strategy in the upcoming D, H and T experimental campaigns in JET-ILW Proceedings Article
In: Europhysics Conference Abstracts, pp. O2.106, 2018.
@inproceedings{1857,
title = {Isotope wall content control strategy in the upcoming D, H and T experimental campaigns in JET-ILW},
author = {I Borodkina and D Douai and D Alegre and D Borodin and S Brezinsek and E Cal and Y Corre and A Drenik and J Gaspar and E Joffrin and C C Klepper and T Loarer and M Maslov and G Sergienko and S Vartanian and T. Wauters and JET Contributors},
year = {2018},
date = {2018-07-01},
booktitle = {Europhysics Conference Abstracts},
volume = {42A},
pages = {O2.106},
abstract = {45th EPS Conference on Plasma Physics, Prage (Czech Republic), 02 - 06 July 2018},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
L Colas; P Jacquet; V Bobkov; M Brix; L Meneses; K Kirov; E. Lerche; C C Klepper; M Goniche; A. Krivska; P. Dumortier; A Czarnecka; JET Contributors
2D mappings of ICRF-induced SOL density modifications on JET Proceedings Article
In: Europhysics Conference Abstracts, pp. O4.101, 2018.
@inproceedings{1859,
title = {2D mappings of ICRF-induced SOL density modifications on JET},
author = {L Colas and P Jacquet and V Bobkov and M Brix and L Meneses and K Kirov and E. Lerche and C C Klepper and M Goniche and A. Krivska and P. Dumortier and A Czarnecka and JET Contributors},
year = {2018},
date = {2018-07-01},
booktitle = {Europhysics Conference Abstracts},
volume = {42A},
pages = {O4.101},
abstract = {45th EPS Conference on Plasma Physics, Prage (Czech Republic), 02 - 06 July 2018},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
B. Van Compernolle; K. Crombé; D. Van Eester
Excitation of slow mode waves by a single strap ICRH antenna at LAPD Proceedings Article
In: Europhysics Conference Abstracts, pp. P5.1051, 2018.
@inproceedings{1867,
title = {Excitation of slow mode waves by a single strap ICRH antenna at LAPD},
author = {B. Van Compernolle and K. Crombé and D. Van Eester},
year = {2018},
date = {2018-07-01},
booktitle = {Europhysics Conference Abstracts},
volume = {42A},
pages = {P5.1051},
abstract = {45th EPS Conference on Plasma Physics, Prage (Czech Republic), 02 - 06 July 2018},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
K. Crombé; A Costic; A Nikiforov; R Ochoulov; I. Shesterikov; Usoltceva M T Verstrynge; H Faugel; H F ü; S Heuraux; J. -M. Noterdaeme; IShTAR team
New Diagnostics Developments on IShTAR Proceedings Article
In: Europhysics Conference Abstracts, pp. P4.1010, 2018.
@inproceedings{1864,
title = {New Diagnostics Developments on IShTAR},
author = {K. Crombé and A Costic and A Nikiforov and R Ochoulov and I. Shesterikov and Usoltceva M T Verstrynge and H Faugel and H F ü and S Heuraux and J. -M. Noterdaeme and IShTAR team},
year = {2018},
date = {2018-07-01},
booktitle = {Europhysics Conference Abstracts},
volume = {42A},
pages = {P4.1010},
abstract = {45th EPS Conference on Plasma Physics, Prage (Czech Republic), 02 - 06 July 2018},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
M Goniche; P Buratti; R J Dumont; C Challis; A Czarnecka; J Graves; P Jacquet; V Kiptily; E. Lerche; M Mantsinen; T P ü; D. Van Eester; JET Contributors
Role of MHD activity triggered by fast ions in tungsten transport in JET hybrid discharges Proceedings Article
In: Europhysics Conference Abstracts, pp. P4.1057, 2018.
@inproceedings{1865,
title = {Role of MHD activity triggered by fast ions in tungsten transport in JET hybrid discharges},
author = {M Goniche and P Buratti and R J Dumont and C Challis and A Czarnecka and J Graves and P Jacquet and V Kiptily and E. Lerche and M Mantsinen and T P ü and D. Van Eester and JET Contributors},
year = {2018},
date = {2018-07-01},
booktitle = {Europhysics Conference Abstracts},
volume = {42A},
pages = {P4.1057},
abstract = {45th EPS Conference on Plasma Physics, Prage (Czech Republic), 02 - 06 July 2018},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
A Kappatou; M Weiland; R Bilato; Y. O. Kazakov; R Dux; V Bobkov; B Geiger; P P ü; Mc R M Dermott; EUROfusion MST1; ASDEX Upgrade teams
CXRS measurements of energetic helium ions in ASDEX Upgrade plasmas heated with a three-ion species ICRH scheme Journal Article
In: Europhysics Conference Abstracts, vol. 42A, pp. O2.105, 2018.
@article{1856,
title = {CXRS measurements of energetic helium ions in ASDEX Upgrade plasmas heated with a three-ion species ICRH scheme},
author = {A Kappatou and M Weiland and R Bilato and Y. O. Kazakov and R Dux and V Bobkov and B Geiger and P P ü and Mc R M Dermott and EUROfusion MST1 and ASDEX Upgrade teams},
year = {2018},
date = {2018-07-01},
journal = {Europhysics Conference Abstracts},
volume = {42A},
pages = {O2.105},
abstract = {45th EPS Conference on Plasma Physics, Prage (Czech Republic), 02 - 06 July 2018},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Y. O. Kazakov; M Schneider; J. Ongena; R Bilato; R Dumont; J M Faustin; E. Lerche; D. Van Eester; J C Wright
Application of three-ion species ICRH scenarios for ITER operations Proceedings Article
In: Europhysics Conference Abstracts, pp. P5.1047, 2018.
@inproceedings{1866,
title = {Application of three-ion species ICRH scenarios for ITER operations},
author = {Y. O. Kazakov and M Schneider and J. Ongena and R Bilato and R Dumont and J M Faustin and E. Lerche and D. Van Eester and J C Wright},
year = {2018},
date = {2018-07-01},
booktitle = {Europhysics Conference Abstracts},
volume = {42A},
pages = {P5.1047},
abstract = {45th EPS Conference on Plasma Physics, Prage (Czech Republic), 02 - 06 July 2018},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
M Nocente; Y. O. Kazakov; V Kiptily; T Craciunescu; J Eriksson; J Faustin; L Giacomelli; G Gorini; C Hellesen; E. Lerche; M Mantsinen; J. Ongena; M Salewski; S Sharapov; M Tardocchi; D. Van Eester; JET Contributors
A quantitative comparison between confined fast ion data and models from radio frequency heating experiments with the three ion scenarios at JET Journal Article
In: Europhysics Conference Abstracts, vol. 42A, pp. O5.103, 2018.
@article{1860,
title = {A quantitative comparison between confined fast ion data and models from radio frequency heating experiments with the three ion scenarios at JET},
author = {M Nocente and Y. O. Kazakov and V Kiptily and T Craciunescu and J Eriksson and J Faustin and L Giacomelli and G Gorini and C Hellesen and E. Lerche and M Mantsinen and J. Ongena and M Salewski and S Sharapov and M Tardocchi and D. Van Eester and JET Contributors},
year = {2018},
date = {2018-07-01},
journal = {Europhysics Conference Abstracts},
volume = {42A},
pages = {O5.103},
abstract = {45th EPS Conference on Plasma Physics, Prage (Czech Republic), 02 - 06 July 2018},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Y Oya; S Masuzaki; M Tokitani; K Azuma; M Oyaidzu; K Isobe; N Asakura; A M Widdowson; K Heinola; S. Jachmich; M Rubel
Correlation of surface chemical states with hydrogen isotope retention in divertor tiles of JET with ITER-Like Wall Journal Article
In: Fusion Engineering and Design, vol. 132, pp. 24 - 28, 2018, ISSN: 0920-3796.
@article{1855,
title = {Correlation of surface chemical states with hydrogen isotope retention in divertor tiles of JET with ITER-Like Wall},
author = {Y Oya and S Masuzaki and M Tokitani and K Azuma and M Oyaidzu and K Isobe and N Asakura and A M Widdowson and K Heinola and S. Jachmich and M Rubel},
url = {http://www.sciencedirect.com/science/article/pii/S0920379618304186},
doi = {https://doi.org/10.1016/j.fusengdes.2018.04.124},
issn = {0920-3796},
year = {2018},
date = {2018-07-01},
journal = {Fusion Engineering and Design},
volume = {132},
pages = {24 - 28},
abstract = {To understand the fuel retention mechanism correlation of surface chemical states and hydrogen isotope retention behavior determined by XPS (X-ray photoelectron spectroscopy) and TDS (Thermal desorption spectroscopy), respectively, for JET ITER-Like Wall samples from operational period 2011–2012 were investigated. It was found that the deposition layer was formed on the upper part of the inner vertical divertor area. At the inner plasma strike point region, the original surface materials, W or Mo, were found, indicating to an erosion-dominated region, but deposition of impurities was also found. Higher heat load would induce the formation of metal carbide. At the outer horizontal divertor tile, mixed material layer was formed with iron as an impurity. TDS showed the H and D desorption behavior and the major D desorption temperature for the upper part of the inner vertical tile was located at 370 $,^circ$C and 530 $,^circ$C. At the strike point region, the D desorption temperature was clearly shifted toward higher release temperatures, indicating the stabilization of D trapping by higher heat load},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
N A Pablant; A Langenberg; A Alonso; J Baldzhun; C D Beidler; M Bitter; S Bozhenkov; K J Brunner; R Burhenn; A Dinklage; G Fuchert; D A Gates; J Geiger; K W Hill; M Hirsch; U Hoefel; Y. O. Kazakov; J Knauer; H Laqua; M Landreman; S Lazerson; H Maassberg; O Marchuk; E Pasch; A Pavone; S Satake; T Schroeder; J Svensson; P Traverso; Y Turkin; J L Velasco; Von A Stechow; F Warmer; G Weir; R C Wolf; D Zhang; W7-X Team
Dependence of the Core Radial Electric Field on Ion and Electron Temperature in W7-X Proceedings Article
In: Europhysics Conference Abstracts, pp. P2.1102, 2018.
@inproceedings{1863,
title = {Dependence of the Core Radial Electric Field on Ion and Electron Temperature in W7-X},
author = {N A Pablant and A Langenberg and A Alonso and J Baldzhun and C D Beidler and M Bitter and S Bozhenkov and K J Brunner and R Burhenn and A Dinklage and G Fuchert and D A Gates and J Geiger and K W Hill and M Hirsch and U Hoefel and Y. O. Kazakov and J Knauer and H Laqua and M Landreman and S Lazerson and H Maassberg and O Marchuk and E Pasch and A Pavone and S Satake and T Schroeder and J Svensson and P Traverso and Y Turkin and J L Velasco and Von A Stechow and F Warmer and G Weir and R C Wolf and D Zhang and W7-X Team},
year = {2018},
date = {2018-07-01},
booktitle = {Europhysics Conference Abstracts},
volume = {42A},
pages = {P2.1102},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
H Strauss; S. Jachmich; E Joffrin; S Gerasimov; V Riccardo; R Paccagnella; J Breslau; G Y Fu; JET Contributors
Reduction of Asymmetric wall force in JET and ITER including Runaway Electrons Proceedings Article
In: Europhysics Conference Abstracts, pp. O3.105, 2018.
@inproceedings{1858,
title = {Reduction of Asymmetric wall force in JET and ITER including Runaway Electrons},
author = {H Strauss and S. Jachmich and E Joffrin and S Gerasimov and V Riccardo and R Paccagnella and J Breslau and G Y Fu and JET Contributors},
year = {2018},
date = {2018-07-01},
booktitle = {Europhysics Conference Abstracts},
volume = {42A},
pages = {O3.105},
abstract = {45th EPS Conference on Plasma Physics, Prage (Czech Republic), 02 - 06 July 2018},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
G. Verdoolaege; L Frassinetti; JET Contributors
Statistical analysis of edge-localized mode timing in JET Proceedings Article
In: Europhysics Conference Abstracts, pp. P2.1078, 2018.
@inproceedings{1862,
title = {Statistical analysis of edge-localized mode timing in JET},
author = {G. Verdoolaege and L Frassinetti and JET Contributors},
year = {2018},
date = {2018-07-01},
booktitle = {Europhysics Conference Abstracts},
volume = {42A},
pages = {P2.1078},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
S Dickheuer; O Marchuk; C Brandt; A Pospieszczyk; A. Goriaev; M Ialovega; B G ö; Y Krasikov; A Krimmer; P Mertens; A Kreter
In situ measurements of the spectral reflectance of metallic mirrors at the Hα line in a low density Ar–H plasma Proceedings Article
In: Review of Scientific Instruments, pp. 063112, 2018.
@inproceedings{1853,
title = {In situ measurements of the spectral reflectance of metallic mirrors at the Hα line in a low density Ar–H plasma},
author = {S Dickheuer and O Marchuk and C Brandt and A Pospieszczyk and A. Goriaev and M Ialovega and B G ö and Y Krasikov and A Krimmer and P Mertens and A Kreter},
year = {2018},
date = {2018-06-01},
booktitle = {Review of Scientific Instruments},
volume = {89},
pages = {063112},
abstract = {The efficient and reliable control and monitoring of the quality of the optical properties of mirrors is an open problem in laboratory plasmas. Until now, the measurement of the reflectance of the first mirrors was based on the methods that require additional light calibration sources. We propose a new technique based on the ratio of the red- and blue-shifted emission signals of the reflected hydrogen atoms which enables the in situ measurement of the spectral reflectance of metallic mirrors in low-density Ar–H or Ar–D plasmas. The spectral reflectance coefficients were measured for C, Al, Ag, Fe, Pd, Ti, Sn, Rh, Mo, and W mirrors installed in the linear magnetized plasma device PSI-2 operating in the pressure range of 0.01-0.1 Pa. The results are obtained for the Hα line using the emission of fast atoms induced by excitation of H atoms through Ar at a plasma-solid interface by applying a negative potential U = −80, łdots, −220 V to the mirror. The agreement between the measured and theoretical data of reflectance is found to be within 10% for the investigated materials (except for C). The spectra also allow us to efficiently determine the material of the mirror.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
M Usoltceva; E Faudot; S Devaux; S Heuraux; J Ledig; G V Zadvitskiy; R Ochoukov; K. Crombé; J. -M. Noterdaeme
Effective collecting area of a cylindrical Langmuir probe in magnetized plasma Proceedings Article
In: Physics of Plasmas, pp. 063518, 2018.
@inproceedings{1852,
title = {Effective collecting area of a cylindrical Langmuir probe in magnetized plasma},
author = {M Usoltceva and E Faudot and S Devaux and S Heuraux and J Ledig and G V Zadvitskiy and R Ochoukov and K. Crombé and J. -M. Noterdaeme},
year = {2018},
date = {2018-06-01},
booktitle = {Physics of Plasmas},
volume = {25},
pages = {063518},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
T Wang; D Mazon; J Svensson; D Li; A Jardin; G. Verdoolaege
Gaussian process tomography for soft x-ray spectroscopy at WEST without equilibrium information Proceedings Article
In: Review of Scientific Instruments, pp. 063505, 2018.
@inproceedings{1854,
title = {Gaussian process tomography for soft x-ray spectroscopy at WEST without equilibrium information},
author = {T Wang and D Mazon and J Svensson and D Li and A Jardin and G. Verdoolaege},
year = {2018},
date = {2018-06-01},
booktitle = {Review of Scientific Instruments},
volume = {89},
pages = {063505},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
T. Wauters; R Brakel; S Brezinsek; A Dinklage; A. Goriaev; H P Laqua; S Marsen; D Moseev; T Stange; G Schlisio; Sunn T Pedersen; O Volzke; U Wenzel; W7-X Team
Wall conditioning by ECRH discharges and He-GDC in the limiter phase of Wendelstein 7-X Journal Article
In: Nuclear Fusion, vol. 58, no. 6, pp. 066013, 2018.
@article{1851,
title = {Wall conditioning by ECRH discharges and He-GDC in the limiter phase of Wendelstein 7-X},
author = {T. Wauters and R Brakel and S Brezinsek and A Dinklage and A. Goriaev and H P Laqua and S Marsen and D Moseev and T Stange and G Schlisio and Sunn T Pedersen and O Volzke and U Wenzel and W7-X Team},
url = {http://stacks.iop.org/0029-5515/58/i=6/a=066013},
year = {2018},
date = {2018-06-01},
journal = {Nuclear Fusion},
volume = {58},
number = {6},
pages = {066013},
abstract = {Wendelstein 7-X (W7-X) relies on wall conditioning to control the density and the impurity content of the plasma. Wall conditioning in the first operation campaign of W7-X consisted of baking at 150 $,^circ$C during 1 week prior to operation, glow discharge conditioning (GDC) in helium (He) and electron cyclotron resonance heating (ECRH) discharges. Additionally, the usage of He-GDC was limited to avoid sputtering and migration of metallic plasma facing components. This presented a unique opportunity for studying the applicability of ECRH discharges for initial wall conditioning on a stellarator, albeit in the carbon limiter configuration. A single envelope curve is observed in the normalised outgassing data that takes into account all ECRH discharges. This illustrates that the majority of discharges operates at the limits of a radiative collapse. Hydrogen recycling dominated the fuelling of ECRH discharges throughout while CO outgassing was found strongest at the start of the campaign. A reduction of recycling was observed throughout the campaign. Temporarily depleting the walls from H and impurities was possible by He-GDC. It was shown that the recycling coefficient in ##IMG## [http://ej.iop.org/images/0029-5515/58/6/066013/nfaab2c9ieqn001.gif] -ECRH plasmas could be reduced and the pulse duration significantly extended by He-'recovery' ECRH plasmas. Good wall conditions were defined by normalised outgassing values below ##IMG## [http://ej.iop.org/images/0029-5515/58/6/066013/nfaab2c9ieqn002.gif] mbar kJ −1 . In absence of ##IMG## [http://ej.iop.org/images/0029-5515/58/6/066013/nfaab2c9ieqn003.gif] -GDC, more than 311 cumulated discharge seconds of ECRH discharges are needed for obtaining lasting low outgassing levels. A release model with two trapping reservoirs could reproduce the normalised outgassing trend, including ECRH and GDC plasma wall interactions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
N Bonanomi; E. Lerche; D. Van Eester; JET Contributors
Turbulent transport stabilization by ICRH minority fast ions in low rotating JET ILW L-mode plasmas Journal Article
In: Nuclear Fusion, vol. 58, no. 5, pp. 056025, 2018.
@article{1850,
title = {Turbulent transport stabilization by ICRH minority fast ions in low rotating JET ILW L-mode plasmas},
author = {N Bonanomi and E. Lerche and D. Van Eester and JET Contributors},
url = {http://stacks.iop.org/0029-5515/58/i=5/a=056025},
year = {2018},
date = {2018-05-01},
journal = {Nuclear Fusion},
volume = {58},
number = {5},
pages = {056025},
abstract = {The first experimental demonstration that fast ion induced stabilization of thermal turbulent transport takes place also at low values of plasma toroidal rotation has been obtained in JET ILW (ITER-like wall) L-mode plasmas with high ( 3 He)-D ICRH (ion cyclotron resonance heating) power. A reduction of the gyro-Bohm normalized ion heat flux and higher values of the normalized ion temperature gradient have been observed at high ICRH power and low NBI (neutral beam injection) power and plasma rotation. Gyrokinetic simulations indicate that ITG (ion temperature gradient) turbulence stabilization induced by the presence of high-energetic 3 He ions is the key mechanism in order to explain the experimental observations. Two main mechanisms have been identified to be responsible for the turbulence stabilization: a linear electrostatic wave-fast particle resonance mechanism and a nonlinear electromagnetic mechanism. The dependence of the stabilization on the 3 He distribution function has also been studied.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
H-T Kim; E. Lerche; JET Contributors
High fusion performance at high T i / T e in JET-ILW baseline plasmas with high NBI heating power and low gas puffing Journal Article
In: Nuclear Fusion, vol. 58, no. 3, pp. 036020, 2018.
@article{1848,
title = {High fusion performance at high T i / T e in JET-ILW baseline plasmas with high NBI heating power and low gas puffing},
author = {H-T Kim and E. Lerche and JET Contributors},
url = {http://stacks.iop.org/0029-5515/58/i=3/a=036020},
year = {2018},
date = {2018-03-01},
journal = {Nuclear Fusion},
volume = {58},
number = {3},
pages = {036020},
abstract = {This paper presents the transport analysis of high density baseline discharges in the 2016 experimental campaign of the Joint European Torus with the ITER-Like Wall (JET-ILW), where a significant increase in the deuterium–deuterium (D–D) fusion neutron rate (~2.8 × 10 16 s −1 ) was achieved with stable high neutral beam injection (NBI) powers of up to 28 MW and low gas puffing. Increase in T i exceeding T e were produced for the first time in baseline discharges despite the high electron density; this enabled a significant increase in the thermal fusion reaction rate. As a result, the new achieved record in fusion performance was much higher than the previous record in the same heating power baseline discharges, where T i = T e . In addition to the decreases in collisionality and the increases in ion heating fraction in the discharges with high NBI power, T i > T e can also be attributed to positive feedback between the high T i / T e ratio and stabilisation of the turbulent heat flux resulting from the ion temperature gradient driven mode. The high T i / T e ratio was correlated with high rotation frequency. Among the discharges with identical beam heating power, higher rotation frequencies were observed when particle fuelling was provided by low gas puffing and pellet injection. This reveals that particle fuelling played a key role for achieving high T i / T e , and the improved fusion performance.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
L Lu; D. Van Eester; K. Crombé; A Kv á
Modelling of radio frequency sheath and fast wave coupling on the realistic ion cyclotron resonant antenna surroundings and the outer wall Journal Article
In: Plasma Physics and Controlled Fusion, vol. 60, no. 3, pp. 035003, 2018.
@article{1849,
title = {Modelling of radio frequency sheath and fast wave coupling on the realistic ion cyclotron resonant antenna surroundings and the outer wall},
author = {L Lu and D. Van Eester and K. Crombé and A Kv á},
url = {http://stacks.iop.org/0741-3335/60/i=3/a=035003},
year = {2018},
date = {2018-03-01},
journal = {Plasma Physics and Controlled Fusion},
volume = {60},
number = {3},
pages = {035003},
abstract = {In order to model the sheath rectification in a realistic geometry over the size of ion cyclotron resonant heating (ICRH) antennas, the self-consistent sheaths and waves for ICH (SSWICH) code couples self-consistently the RF wave propagation and the DC SOL biasing via nonlinear RF and DC sheath boundary conditions applied at plasma/wall interfaces. A first version of SSWICH had 2D (toroidal and radial) geometry, rectangular walls either normal or parallel to the confinement magnetic field B 0 and only included the evanescent slow wave (SW) excited parasitically by the ICRH antenna. The main wave for plasma heating, the fast wave (FW) plays no role on the sheath excitation in this version. A new version of the code, 2D SSWICH-full wave, was developed based on the COMSOL software, to accommodate full RF field polarization and shaped walls tilted with respect to B 0 . SSWICH-full wave simulations have shown the mode conversion of FW into SW occurring at the sharp corners where the boundary shape varies rapidly. It has also evidenced `far-field' sheath oscillations appearing at the shaped walls with a relatively long magnetic connection length to the antenna, that are only accessible to the propagating FW. Joint simulation, conducted by SSWICH-full wave within a multi-2D approach excited using the 3D wave coupling code (RAPLICASOL), has recovered the double-hump poloidal structure measured in the experimental temperature and potential maps when only the SW is modelled. The FW contribution on the potential poloidal structure seems to be affected by the 3D effects, which was ignored in the current stage. Finally, SSWICH-full wave simulation revealed the left–right asymmetry that has been observed extensively in the unbalanced strap feeding experiments, suggesting that the spatial proximity effects in RF sheath excitation, studied for SW only previously, is still important in the vicinity of the wave launcher under full wave polarizations.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
I Monakhov; P. Dumortier; E. Lerche; JET Contributors
ICRH antenna S -matrix measurements and plasma coupling characterisation at JET Journal Article
In: Nuclear Fusion, vol. 58, no. 3, pp. 036012, 2018.
@article{1847,
title = {ICRH antenna S -matrix measurements and plasma coupling characterisation at JET},
author = {I Monakhov and P. Dumortier and E. Lerche and JET Contributors},
url = {http://stacks.iop.org/0029-5515/58/i=4/a=046012},
year = {2018},
date = {2018-03-01},
journal = {Nuclear Fusion},
volume = {58},
number = {3},
pages = {036012},
abstract = {The paper is dedicated to the characterisation of multi-strap ICRH antenna coupling to plasma. Relevance of traditional concept of coupling resistance to antennas with mutually coupled straps is revised and the importance of antenna port excitation consistency for application of the concept is highlighted. A method of antenna S -matrix measurement in presence of plasma is discussed allowing deeper insight into the problem of antenna-plasma coupling. The method is based entirely on the RF plant hardware and control facilities available at JET and it involves application of variable phasing between the antenna straps during the RF plant operations at >100 kW. Unlike traditional techniques relying on low-power (~10 mW) network analysers, the applied antenna voltage amplitudes are relevant to practical conditions of ICRH operations; crucially, they are high enough to minimise possible effects of antenna loading non-linearity due to the RF sheath effects and other phenomena which could affect low-power measurements. The method has been successfully applied at JET to conventional 4-port ICRH antennas energised at frequencies of 33 MHz, 42 MHz and 51 MHz during L-mode plasma discharges while different gas injection modules (GIMs) were used to maintain comparable plasma densities during the pulses. The S -matrix assessment and its subsequent processing yielding `global' antenna coupling resistances in conditions of equalised port maximum voltages allowed consistent description of antenna coupling to plasma at different strap phasing, operational frequencies and applied GIMs. Comprehensive experimental characterisation of mutually coupled antenna straps in presence of plasma also provided a unique opportunity for in-depth verification of TOPICA computer simulations.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
N Bonanomi; D. Van Eester; JET contributors
Effects of nitrogen seeding on core ion thermal transport in JET ILW L-mode plasmas Journal Article
In: Nuclear Fusion, vol. 58, no. 2, pp. 026028, 2018.
@article{1845,
title = {Effects of nitrogen seeding on core ion thermal transport in JET ILW L-mode plasmas},
author = {N Bonanomi and D. Van Eester and JET contributors},
url = {http://stacks.iop.org/0029-5515/58/i=2/a=026028},
year = {2018},
date = {2018-02-01},
journal = {Nuclear Fusion},
volume = {58},
number = {2},
pages = {026028},
abstract = {A set of experiments was carried out in JET ILW (Joint European Torus with ITER-Like Wall) L-mode plasmas in order to study the effects of light impurities on core ion thermal transport. N was puffed into some discharges and its profile was measured by active Charge Exchange diagnostics, while ICRH power was deposited on- and off-axis in ##IMG## [http://ej.iop.org/images/0029-5515/58/2/026028/nfaa9e7cieqn001.gif] $(hspace0pt^3rm He)-D$ minority scheme in order to have a scan of local heat flux at constant total power with and without N injection. Experimentally, the ion temperature profiles are more peaked for similar heat fluxes when N is injected in the plasma. Gyro-kinetic simulations using the GENE code indicate that a stabilization of Ion Temperature Gradient driven turbulent transport due to main ion dilution and to changes in ##IMG## [http://ej.iop.org/images/0029-5515/58/2/026028/nfaa9e7cieqn002.gif] $T_e/T_i$ and s / q is responsible of the enhanced peaking. The quasi-linear models TGLF and QuaLiKiz are tested against the experimental and the gyro-kinetic results.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
D Douai; T. Wauters; EUROfusion MST1 Team
Development of helium electron cyclotron wall conditioning on TCV Journal Article
In: Nuclear Fusion, vol. 58, no. 2, pp. 026018, 2018.
@article{1844,
title = {Development of helium electron cyclotron wall conditioning on TCV},
author = {D Douai and T. Wauters and EUROfusion MST1 Team},
url = {http://stacks.iop.org/0029-5515/58/i=2/a=026018},
year = {2018},
date = {2018-02-01},
journal = {Nuclear Fusion},
volume = {58},
number = {2},
pages = {026018},
abstract = {JT-60SA envisions electron cyclotron wall conditioning (ECWC), as wall conditioning method in the presence of the toroidal field to control fuel and impurity recycling and to improve plasma performance and reproducibility. This paper reports on Helium ECWC experiments on TCV in support of JT-60SA operation. Nearly sixty Helium conditioning discharges have been successfully produced in TCV, at a toroidal field B T = 1.3 or 1.54 T, with gyrotrons at 82.7 GHz in X2 mode, mimicking ECWC operation in JT-60SA at the second harmonic of the EC wave. Discharge parameters were tuned in order to (i) minimize the time for the onset of ECWC plasmas, thus minimizing absorption of stray radiation by in-vessel components, (ii) improve discharge homogeneity by extending the discharge vertically and radially, and wall coverage, in particular of inboard surfaces where JT-60SA plasmas will be initiated, (iii) assess the efficiency of He-ECWC to deplete carbon walls from fuel. An optimized combination of vertical and radial magnetic fields, with amplitudes typically 0.1 to 0.6% of that of B T , has been determined, which resulted in lowest breakdown time, improved wall coverage and enhanced fuel removal. A standard ohmic D 2 -plasma could be then sustained, whereas it would not have been possible without He-ECWC.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A V Krasilnikov; E. Lerche; D. Van Eester; JET contributors
Evidence of 9 Be + p nuclear reactions during 2 ω CH and hydrogen minority ICRH in JET-ILW hydrogen and deuterium plasmas Journal Article
In: Nuclear Fusion, vol. 58, no. 2, pp. 026033, 2018.
@article{1846,
title = {Evidence of 9 Be + p nuclear reactions during 2 ω CH and hydrogen minority ICRH in JET-ILW hydrogen and deuterium plasmas},
author = {A V Krasilnikov and E. Lerche and D. Van Eester and JET contributors},
url = {http://stacks.iop.org/0029-5515/58/i=2/a=026033},
year = {2018},
date = {2018-02-01},
journal = {Nuclear Fusion},
volume = {58},
number = {2},
pages = {026033},
abstract = {The intensity of 9 Be + p nuclear fusion reactions was experimentally studied during second harmonic (2 ω CH ) ion-cyclotron resonance heating (ICRH) and further analyzed during fundamental hydrogen minority ICRH of JET-ILW hydrogen and deuterium plasmas. In relatively low-density plasmas with a high ICRH power, a population of fast H + ions was created and measured by neutral particle analyzers. Primary and secondary nuclear reaction products, due to 9 Be + p interaction, were observed with fast ion loss detectors, γ -ray spectrometers and neutron flux monitors and spectrometers. The possibility of using 9 Be( p , d )2 α and 9 Be( p , α ) 6 Li nuclear reactions to create a population of fast alpha particles and study their behaviour in non-active stage of ITER operation is discussed in the paper.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
C F Maggi; E. Lerche; JET Contributors
Isotope effects on L-H threshold and confinement in tokamak plasmas Journal Article
In: Plasma Physics and Controlled Fusion, vol. 60, no. 1, pp. 014045, 2018.
@article{1842,
title = {Isotope effects on L-H threshold and confinement in tokamak plasmas},
author = {C F Maggi and E. Lerche and JET Contributors},
url = {http://stacks.iop.org/0741-3335/60/i=1/a=014045},
year = {2018},
date = {2018-01-01},
journal = {Plasma Physics and Controlled Fusion},
volume = {60},
number = {1},
pages = {014045},
abstract = {The dependence of plasma transport and confinement on the main hydrogenic ion isotope mass is of fundamental importance for understanding turbulent transport and, therefore, for accurate extrapolations of confinement from present tokamak experiments, which typically use a single hydrogen isotope, to burning plasmas such as ITER, which will operate in deuterium–tritium mixtures. Knowledge of the dependence of plasma properties and edge transport barrier formation on main ion species is critical in view of the initial, low-activation phase of ITER operations in hydrogen or helium and of its implications on the subsequent operation in deuterium–tritium. The favourable scaling of global energy confinement time with isotope mass, which has been observed in many tokamak experiments, remains largely unexplained theoretically. Moreover, the mass scaling observed in experiments varies depending on the plasma edge conditions. In preparation for upcoming deuterium–tritium experiments in the JET tokamak with the ITER-like Be/W Wall (JET-ILW), a thorough experimental investigation of isotope effects in hydrogen, deuterium and tritium plasmas is being carried out, in order to provide stringent tests of plasma energy, particle and momentum transport models. Recent hydrogen and deuterium isotope experiments in JET-ILW on L-H power threshold, L-mode and H-mode confinement are reviewed and discussed in the context of past and more recent isotope experiments in tokamak plasmas, highlighting common elements as well as contrasting observations that have been reported. The experimental findings are discussed in the context of fundamental aspects of plasma transport models.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
V V Plyusnin; S. Jachmich
In: Nuclear Fusion, vol. 58, no. 1, pp. 016014, 2018.
@article{1843,
title = {Comparison of runaway electron generation parameters in small, medium-sized and large tokamaks—A survey of experiments in COMPASS, TCV, ASDEX-Upgrade and JET},
author = {V V Plyusnin and S. Jachmich},
url = {http://stacks.iop.org/0029-5515/58/i=1/a=016014},
year = {2018},
date = {2018-01-01},
journal = {Nuclear Fusion},
volume = {58},
number = {1},
pages = {016014},
abstract = {This paper presents a survey of the experiments on runaway electrons (RE) carried out recently in frames of EUROFusion Consortium in different tokamaks: COMPASS, ASDEX-Upgrade, TCV and JET. Massive gas injection (MGI) has been used in different scenarios for RE generation in small and medium-sized tokamaks to elaborate the most efficient and reliable ones for future RE experiments. New data on RE generated at disruptions in COMPASS and ASDEX-Upgrade was collected and added to the JET database. Different accessible parameters of disruptions, such as current quench rate, conversion rate of plasma current into runaways, etc have been analysed for each tokamak and compared to JET data. It was shown, that tokamaks with larger geometrical sizes provide the wider limits for spatial and temporal variation of plasma parameters during disruptions, thus extending the parameter space for RE generation. The second part of experiments was dedicated to study of RE generation in stationary discharges in COMPASS, TCV and JET. Injection of Ne/Ar have been used to mock-up the JET MGI runaway suppression experiments. Secondary RE avalanching was identified and quantified for the first time in the TCV tokamak in RE generating discharges after massive Ne injection. Simulations of the primary RE generation and secondary avalanching dynamics in stationary discharges has demonstrated that RE current fraction created via avalanching could achieve up to 70–75% of the total plasma current in TCV. Relaxations which are reminiscent the phenomena associated to the kinetic instability driven by RE have been detected in RE discharges in TCV. Macroscopic parameters of RE dominating discharges in TCV before and after onset of the instability fit well to the empirical instability criterion, which was established in the early tokamaks and examined by results of recent numerical simulations.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2017
A Drenik; T. Wauters; EUROfusion MST1 Team; JET contributors
Evaluation of the plasma hydrogen isotope content by residual gas analysis at JET and AUG Journal Article
In: Physica Scripta, vol. 2017, no. T170, pp. 014021, 2017.
@article{1832,
title = {Evaluation of the plasma hydrogen isotope content by residual gas analysis at JET and AUG},
author = {A Drenik and T. Wauters and EUROfusion MST1 Team and JET contributors},
url = {http://stacks.iop.org/1402-4896/2017/i=T170/a=014021},
year = {2017},
date = {2017-12-01},
journal = {Physica Scripta},
volume = {2017},
number = {T170},
pages = {014021},
abstract = {The isotope content of the plasma reflects on the dynamics of isotope changeover experiments, efficiency of wall conditioning and the performance of a fusion device in the active phase of operation. The assessment of the isotope ratio of hydrogen and methane molecules is used as a novel method of assessing the plasma isotope ratios at JET and ASDEX-Upgrade (AUG). The isotope ratios of both molecules in general shows similar trends as the isotope ratio detected by other diagnostics. At JET, the absolute values of RGA signals are in relatively good agreement with each other and with spectroscopy data, while at AUG the deviation from neutral particle analyser data are larger, and the results show a consistent spatial distribution of the isotope ratio. It is further shown that the isotope ratio of the hydrogen molecule can be used to study the degree of dissociation of the injected gas during changeover experiments.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A Huber; S. Jachmich; contributors
The near infrared imaging system for the real-time protection of the JET ITER-like wall Journal Article
In: Physica Scripta, vol. 2017, no. T170, pp. 014027, 2017.
@article{1833,
title = {The near infrared imaging system for the real-time protection of the JET ITER-like wall},
author = {A Huber and S. Jachmich and contributors},
url = {http://stacks.iop.org/1402-4896/2017/i=T170/a=014027},
year = {2017},
date = {2017-12-01},
journal = {Physica Scripta},
volume = {2017},
number = {T170},
pages = {014027},
abstract = {This paper describes the design, implementation and operation of the near infrared (NIR) imaging diagnostic system of the JET ITER-like wall (JET-ILW) plasma experiment and its integration into the existing JET protection architecture. The imaging system comprises four wide-angle views, four tangential divertor views, and two top views of the divertor covering 66% of the first wall and up to 43% of the divertor. The operation temperature ranges which must be observed by the NIR protection cameras are, for the materials used on JET: Be 700 $,^circ$C–1400 $,^circ$C; W coating 700 $,^circ$C–1370 $,^circ$C; W bulk 700 $,^circ$C–1400 $,^circ$C. The Real-Time Protection system operates routinely since 2011 and successfully demonstrated its capability to avoid the overheating of the main chamber beryllium wall as well as of the divertor W and W-coated carbon fibre composite (CFC) tiles. During this period, less than 0.5% of the terminated discharges were aborted by a malfunction of the system. About 2%–3% of the discharges were terminated due to the detection of actual hot spots.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
S Masuzaki; S. Jachmich; contributors
Analyses of microstructure, composition and retention of hydrogen isotopes in divertor tiles of JET with the ITER-like wall Journal Article
In: Physica Scripta, vol. 2017, no. T170, pp. 014031, 2017.
@article{1834,
title = {Analyses of microstructure, composition and retention of hydrogen isotopes in divertor tiles of JET with the ITER-like wall},
author = {S Masuzaki and S. Jachmich and contributors},
url = {http://stacks.iop.org/1402-4896/2017/i=T170/a=014031},
year = {2017},
date = {2017-12-01},
journal = {Physica Scripta},
volume = {2017},
number = {T170},
pages = {014031},
abstract = {Results of the comprehensive surface analyses of divertor tiles and dusts retrieved from JET after the first ITER-like wall campaign (2011–2012) are presented. The samples cored from the divertor tiles were analyzed. Numerous nano-size bubble-like structures were observed in the deposition layer on the apron of the inner divertor tile, and a beryllium dust with the same structures were found in the matter collected from the inner divertor after the campaign. This suggests that the nano-size bubble-like structures can make the deposition layer to become brittle and may lead to cracking followed by dust generation. X-ray photoelectron spectroscopy analyses of chemical states of species in the deposition layers identified the formation of beryllium-tungsten intermetallic compounds on an inner vertical tile. Different tritium retention profiles along the divertor tiles were observed at the top surfaces and at deeper regions of the tiles by using the imaging plate technique.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A Murari; E. Lerche
On efficiency and interpretation of sawteeth pacing with on-axis ICRH modulation in JET Journal Article
In: Nuclear Fusion, vol. 57, no. 12, pp. 126057, 2017.
@article{1831,
title = {On efficiency and interpretation of sawteeth pacing with on-axis ICRH modulation in JET},
author = {A Murari and E. Lerche},
url = {http://stacks.iop.org/0029-5515/57/i=12/a=126057},
year = {2017},
date = {2017-12-01},
journal = {Nuclear Fusion},
volume = {57},
number = {12},
pages = {126057},
abstract = {In metallic machines ICRH heating is playing an increasingly important role. One of its most recent applications on the Joint Europena Torus (JET) is sawtooth control by ICRH modulation, for avoiding triggering dangerous neo-classical tearing modes (NTMs) and counteracting impurity accumulation. Some of the main difficulties of these experiments are the assessment of the synchronization efficiency and the understanding of the main physical mechanisms at play. In this paper, three independent classes of statistical indicators are introduced to address these issues: Recurrence Plots, Convergent Cross Mapping and Transfer Entropy. The application to JET experiments with the ILW shows that the proposed indicators agree quite well among themselves and provide sound estimates of the efficiency of the synchronisation scheme investigated. They also support, with a shot to shot basis analysis and an estimate of the uncertainties, the interpretation that the fast ions play a fundamental role in the stabilization of the sawteeth, in both L and H mode. Proposals for experiments to be carried out in the future to consolidate the interpretation of the results are discussed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
M. Tripsky; T. Wauters; A. I. Lyssoivan; I. Stepanov; D. Van Eester; M. Van Schoor
A PIC-MCC code RFdinity1d for simulation of discharge initiation by ICRF antenna Journal Article
In: Nuclear Fusion, vol. 57, no. 12, pp. 126043, 2017.
@article{1830,
title = {A PIC-MCC code RFdinity1d for simulation of discharge initiation by ICRF antenna},
author = {M. Tripsky and T. Wauters and A. I. Lyssoivan and I. Stepanov and D. Van Eester and M. Van Schoor},
url = {http://stacks.iop.org/0029-5515/57/i=12/a=126043},
year = {2017},
date = {2017-12-01},
journal = {Nuclear Fusion},
volume = {57},
number = {12},
pages = {126043},
abstract = {Discharges produced and sustained by ion cyclotron range of frequency (ICRF) waves in absence of plasma current will be used on ITER for (ion cyclotron-) wall conditioning (ICWC, ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn001.gif] $T_e = 3rm-5$ eV, ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn002.gif] $n_e < 10^18$ ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn003.gif] $rm m^-3$ ). In this paper, we present the 1D particle-in-cell Monte Carlo collision (PIC-MCC) RFdinity1d for the study the breakdown phase of ICRF discharges, and its dependency on the RF discharge parameters (i) antenna input power P i , (ii) RF frequency f , (iii) shape of the electric field and (iv) the neutral gas pressure ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn004.gif] $p_H_2$ . The code traces the motion of both electrons and ions in a narrow bundle of magnetic field lines close to the antenna straps. The charged particles are accelerated in the parallel direction with respect to the magnetic field B T by two electric fields: (i) the vacuum RF field of the ICRF antenna ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn005.gif] $E_z^rm RF$ and (ii) the electrostatic field ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn006.gif] $E_z^P$ determined by the solution of Poisson's equation. The electron density evolution in simulations follows exponential increase, ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn007.gif] $dotn_e sim nu_rm ion t $ . The ionization rate varies with increasing electron density as different mechanisms become important. The charged particles are affected solely by the antenna RF field ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn008.gif] $E_z^rm RF$ at low electron density ( ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn009.gif] $n_e < 10^11$ ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn010.gif] $rm m^-3$ , ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn011.gif] $łeft vert E_z^rm RF right vert gg łeft vert E_z^P right vert $ ). At higher densities, when the electrostatic field ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn012.gif] $E_z^P$ is comparable to the antenna RF field ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn013.gif] $E_z^rm RF$ , the ionization frequency reaches the maximum. Plasma oscillations propagating toroidally away from the antenna are observed. The simulated energy distributions of ions and electrons at ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn014.gif] $n_e sim 10^15$ ##IMG## [http://ej.iop.org/images/0029-5515/57/12/126043/nfaa8446ieqn015.gif] $rm m^-3$ correspond a power-law Kappa energy distribution. This energy distribution was also observed in NPA measurements at ASDEX Upgrade in ICWC experiments.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A Bader; A. Messiaen; R. Ragona; D. Van Eester
Integrating a distributed antenna in DEMO: Requirements and challenges Journal Article
In: Fusion Engineering and Design, vol. 123, pp. 431 - 434, 2017, ISSN: 0920-3796, (Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016).
@article{1827,
title = {Integrating a distributed antenna in DEMO: Requirements and challenges},
author = {A Bader and A. Messiaen and R. Ragona and D. Van Eester},
url = {http://www.sciencedirect.com/science/article/pii/S0920379617302387},
doi = {https://doi.org/10.1016/j.fusengdes.2017.03.035},
issn = {0920-3796},
year = {2017},
date = {2017-11-01},
journal = {Fusion Engineering and Design},
volume = {123},
pages = {431 - 434},
note = {Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
F. Durodié; P. Dumortier; T Blackman; M Graham; W Helou; E. Lerche; I Monakhov; C Noble; E Wooldridge; R H Goulding; P Jacquet; M Kaufman
Commissioning and first results of the reinstated JET ICRF ILA Journal Article
In: Fusion Engineering and Design, vol. 123, pp. 285 - 288, 2017, ISSN: 0920-3796, (Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016).
@article{1824,
title = {Commissioning and first results of the reinstated JET ICRF ILA},
author = {F. Durodié and P. Dumortier and T Blackman and M Graham and W Helou and E. Lerche and I Monakhov and C Noble and E Wooldridge and R H Goulding and P Jacquet and M Kaufman},
url = {http://www.sciencedirect.com/science/article/pii/S092037961730594X},
doi = {https://doi.org/10.1016/j.fusengdes.2017.05.050},
issn = {0920-3796},
year = {2017},
date = {2017-11-01},
journal = {Fusion Engineering and Design},
volume = {123},
pages = {285 - 288},
note = {Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
F. Durodié; P. Dumortier; E. Lerche; A. Kv á; D. Van Eester
ITER-like antenna for JET first results of the advanced matching control algorithms Journal Article
In: Fusion Engineering and Design, vol. 123, pp. 253 - 258, 2017, ISSN: 0920-3796, (Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016).
@article{1823,
title = {ITER-like antenna for JET first results of the advanced matching control algorithms},
author = {F. Durodié and P. Dumortier and E. Lerche and A. Kv á and D. Van Eester},
url = {http://www.sciencedirect.com/science/article/pii/S0920379617306713},
doi = {https://doi.org/10.1016/j.fusengdes.2017.05.113},
issn = {0920-3796},
year = {2017},
date = {2017-11-01},
journal = {Fusion Engineering and Design},
volume = {123},
pages = {253 - 258},
note = {Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
M Lennholm; E. Lerche
Real time control developments at JET in preparation for deuterium-tritium operation Journal Article
In: Fusion Engineering and Design, vol. 123, pp. 535 - 540, 2017, ISSN: 0920-3796, (Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016).
@article{1828,
title = {Real time control developments at JET in preparation for deuterium-tritium operation},
author = {M Lennholm and E. Lerche},
url = {http://www.sciencedirect.com/science/article/pii/S0920379617305677},
doi = {https://doi.org/10.1016/j.fusengdes.2017.05.023},
issn = {0920-3796},
year = {2017},
date = {2017-11-01},
journal = {Fusion Engineering and Design},
volume = {123},
pages = {535 - 540},
note = {Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
F. Louche; T. Wauters; R. Ragona; F. Durodié; A. I. Lyssoivan; A. Messiaen; J. Ongena; M. Van Schoor
Design of an ICRF system for plasma-wall interactions and RF plasma production studies on TOMAS Journal Article
In: Fusion Engineering and Design, vol. 123, pp. 317 - 320, 2017, ISSN: 0920-3796, (Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016).
@article{1826,
title = {Design of an ICRF system for plasma-wall interactions and RF plasma production studies on TOMAS},
author = {F. Louche and T. Wauters and R. Ragona and F. Durodié and A. I. Lyssoivan and A. Messiaen and J. Ongena and M. Van Schoor},
url = {http://www.sciencedirect.com/science/article/pii/S0920379617305264},
doi = {https://doi.org/10.1016/j.fusengdes.2017.04.123},
issn = {0920-3796},
year = {2017},
date = {2017-11-01},
journal = {Fusion Engineering and Design},
volume = {123},
pages = {317 - 320},
note = {Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
R. Ragona; A. Messiaen
Multi-section Traveling Wave Antenna for heating of large machines as DEMO Journal Article
In: Fusion Engineering and Design, vol. 123, pp. 232 - 235, 2017, ISSN: 0920-3796, (Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016).
@article{1822,
title = {Multi-section Traveling Wave Antenna for heating of large machines as DEMO},
author = {R. Ragona and A. Messiaen},
url = {http://www.sciencedirect.com/science/article/pii/S0920379617301618},
doi = {https://doi.org/10.1016/j.fusengdes.2017.02.068},
issn = {0920-3796},
year = {2017},
date = {2017-11-01},
journal = {Fusion Engineering and Design},
volume = {123},
pages = {232 - 235},
note = {Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
B Schweer; J. Ongena; F. Durodié; A. Krivska; F. Louche; A. Messiaen; M. Van Schoor; M. Vervier
Development of an ICRH antenna system at W7-X for plasma heating and wall conditioning Journal Article
In: Fusion Engineering and Design, vol. 123, pp. 303 - 308, 2017, ISSN: 0920-3796, (Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016).
@article{1825,
title = {Development of an ICRH antenna system at W7-X for plasma heating and wall conditioning},
author = {B Schweer and J. Ongena and F. Durodié and A. Krivska and F. Louche and A. Messiaen and M. Van Schoor and M. Vervier},
url = {http://www.sciencedirect.com/science/article/pii/S0920379617305641},
doi = {https://doi.org/10.1016/j.fusengdes.2017.05.019},
issn = {0920-3796},
year = {2017},
date = {2017-11-01},
journal = {Fusion Engineering and Design},
volume = {123},
pages = {303 - 308},
note = {Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A Shabbir; G. Verdoolaege
Classification of ELM types in Joint European Torus based on global plasma parameters using discriminant analysis Journal Article
In: Fusion Engineering and Design, vol. 123, pp. 717 - 721, 2017, ISSN: 0920-3796, (Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016).
@article{1829,
title = {Classification of ELM types in Joint European Torus based on global plasma parameters using discriminant analysis},
author = {A Shabbir and G. Verdoolaege},
url = {http://www.sciencedirect.com/science/article/pii/S0920379617306506},
doi = {https://doi.org/10.1016/j.fusengdes.2017.05.101},
issn = {0920-3796},
year = {2017},
date = {2017-11-01},
journal = {Fusion Engineering and Design},
volume = {123},
pages = {717 - 721},
note = {Proceedings of the 29th Symposium on Fusion Technology (SOFT-29) Prague, Czech Republic, September 5-9, 2016},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
W Zhang; A. Krivska
Radio frequency heating induced edge plasma convection: self-consistent simulations and experiments on ASDEX Upgrade Journal Article
In: Nuclear Fusion, vol. 57, no. 11, pp. 116048, 2017.
@article{1821,
title = {Radio frequency heating induced edge plasma convection: self-consistent simulations and experiments on ASDEX Upgrade},
author = {W Zhang and A. Krivska},
url = {http://stacks.iop.org/0029-5515/57/i=11/a=116048},
year = {2017},
date = {2017-11-01},
journal = {Nuclear Fusion},
volume = {57},
number = {11},
pages = {116048},
abstract = {Plasma heating with waves in the ion cyclotron range of frequency (ICRF) affects the edge plasma and the edge plasma affects the ICRF heating. In simulations, these nonlinear ICRF—edge plasma interactions have been self-consistently simulated by running the EMC3-EIRENE, RAPLICASOL and SSWICH codes in an iterative way on ASDEX Upgrade for the first time. In experiments, the edge plasma convection induced by powered 3-strap antennas is measured with the antenna embedded reflectometers for the first time. Both the simulation and experimental results indicate that the ICRF induced convective cells are most significant on the top and bottom of the antennas; the edge plasma convection induced by 3-strap antennas in optimized antenna feeding configuration (dipole phasing, power ratio between the center and outer straps ~1.5) is smallest among the studied cases. The simulation results also suggest that compared to the 2-strap antennas, the 3-strap antennas can significantly reduce the plasma convection associated with the radio-frequency sheaths, even with unfavorable power balance between the straps in dipole phasing.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
G. Bosia; R. Ragona
Current Drive Operation in a In-blanket ICRF Ring Array Proceedings Article
In: 22 Topical Conference on Radio-Frequency Power in Plasmas, 2017.
@inproceedings{1802,
title = {Current Drive Operation in a In-blanket ICRF Ring Array},
author = {G. Bosia and R. Ragona},
year = {2017},
date = {2017-10-01},
booktitle = {22 Topical Conference on Radio-Frequency Power in Plasmas},
volume = {157},
number = {03006},
abstract = {EPJ Web of Conferences 157, 02013 (2017), Aix-en-Provence, France, May 30 - June 2, 2017},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
S Coda; G. Verdoolaege; T. Wauters; EUROfusion MST1 MST1 team
Overview of the TCV tokamak program: scientific progress and facility upgrades Journal Article
In: Nuclear Fusion, vol. 57, no. 10, pp. 102011, 2017.
@article{1795,
title = {Overview of the TCV tokamak program: scientific progress and facility upgrades},
author = {S Coda and G. Verdoolaege and T. Wauters and EUROfusion MST1 MST1 team},
url = {http://stacks.iop.org/0029-5515/57/i=10/a=102011},
year = {2017},
date = {2017-10-01},
journal = {Nuclear Fusion},
volume = {57},
number = {10},
pages = {102011},
abstract = {The TCV tokamak is augmenting its unique historical capabilities (strong shaping, strong electron heating) with ion heating, additional electron heating compatible with high densities, and variable divertor geometry, in a multifaceted upgrade program designed to broaden its operational range without sacrificing its fundamental flexibility. The TCV program is rooted in a three-pronged approach aimed at ITER support, explorations towards DEMO, and fundamental research. A 1 MW, tangential neutral beam injector (NBI) was recently installed and promptly extended the TCV parameter range, with record ion temperatures and toroidal rotation velocities and measurable neutral-beam current drive. ITER-relevant scenario development has received particular attention, with strategies aimed at maximizing performance through optimized discharge trajectories to avoid MHD instabilities, such as peeling-ballooning and neoclassical tearing modes. Experiments on exhaust physics have focused particularly on detachment, a necessary step to a DEMO reactor, in a comprehensive set of conventional and advanced divertor concepts. The specific theoretical prediction of an enhanced radiation region between the two X-points in the low-field-side snowflake-minus configuration was experimentally confirmed. Fundamental investigations of the power decay length in the scrape-off layer (SOL) are progressing rapidly, again in widely varying configurations and in both D and He plasmas; in particular, the double decay length in L-mode limited plasmas was found to be replaced by a single length at high SOL resistivity. Experiments on disruption mitigation by massive gas injection and electron-cyclotron resonance heating (ECRH) have begun in earnest, in parallel with studies of runaway electron generation and control, in both stable and disruptive conditions; a quiescent runaway beam carrying the entire electrical current appears to develop in some cases. Developments in plasma control have benefited from progress in individual controller design and have evolved steadily towards controller integration, mostly within an environment supervised by a tokamak profile control simulator. TCV has demonstrated effective wall conditioning with ECRH in He in support of the preparations for JT-60SA operation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
L Colas; A. Krivska; D. Van Eester; K. Crombé; F. Louche
SOL RF physics modelling in Europe, in support of ICRF experiments Proceedings Article
In: 22 Topical Conference on Radio-Frequency Power in Plasmas, 2017.
@inproceedings{1798,
title = {SOL RF physics modelling in Europe, in support of ICRF experiments},
author = {L Colas and A. Krivska and D. Van Eester and K. Crombé and F. Louche},
year = {2017},
date = {2017-10-01},
booktitle = {22 Topical Conference on Radio-Frequency Power in Plasmas},
volume = {157},
number = {01001},
abstract = {EPJ Web of Conferences 157, 01001 (2017), Aix-en-Provence, France, May 30 - June 2, 2017},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}