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Title: Statistical comparison of ICRF and NBI heating performance in JET-ILW L-mode plasmas

Abstract

After the change over from the C-wall to the ITER-like Be/W wall (ILW) in JET, the radiation losses during ICRF heating have increased and are now substantially larger than those observed with NBI at the same power levels, in spite of the similar global plasma energies reached with the two heating systems. A comparison of the NBI and ICRF performances in the JET-ILW experiments, based on a statistical analysis of ∼3000 L-mode discharges, will be presented.

Authors:
;  [1]; ; ; ; ; ;  [2]; ; ;  [3];  [4];  [5];  [6];
  1. Association EURATOM-Belgian State, LPP-ERM-KMS, TEC partner, Brussels (Belgium)
  2. Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)
  3. Max-Planck-Institut für Plasmaphysik, EURATOM-Assoziation, Garching (Germany)
  4. CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France)
  5. Association Euratom-IPPLM, Hery 23, 01-497 Warsaw (Poland)
  6. FOM Institute DIFFER, Euratom Association, P.O. Box 1207, Nieuwegein (Netherlands)
Publication Date:
OSTI Identifier:
22263861
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1580; Journal Issue: 1; Conference: 20. topical conference on radiofrequency power in plasmas, Sorrento (Italy), 25-28 Jun 2013; Other Information: (c) 2014 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BEAM INJECTION HEATING; COMPARATIVE EVALUATIONS; HEATING SYSTEMS; ICR HEATING; ITER TOKAMAK; L-MODE PLASMA CONFINEMENT; NEUTRAL ATOM BEAM INJECTION; PLASMA

Citation Formats

Lerche, E., Van Eester, D., Jacquet, Ph., Mayoral, M.-L., Graham, M., Matthews, G., Monakhov, I., Rimini, F., Bobkov, V., Neu, R., Puetterich, T., Colas, L., Czarnecka, A., Vries, P. de, and Collaboration: JET-EFDA Contributors. Statistical comparison of ICRF and NBI heating performance in JET-ILW L-mode plasmas. United States: N. p., 2014. Web. doi:10.1063/1.4864531.
Lerche, E., Van Eester, D., Jacquet, Ph., Mayoral, M.-L., Graham, M., Matthews, G., Monakhov, I., Rimini, F., Bobkov, V., Neu, R., Puetterich, T., Colas, L., Czarnecka, A., Vries, P. de, & Collaboration: JET-EFDA Contributors. Statistical comparison of ICRF and NBI heating performance in JET-ILW L-mode plasmas. United States. doi:10.1063/1.4864531.
Lerche, E., Van Eester, D., Jacquet, Ph., Mayoral, M.-L., Graham, M., Matthews, G., Monakhov, I., Rimini, F., Bobkov, V., Neu, R., Puetterich, T., Colas, L., Czarnecka, A., Vries, P. de, and Collaboration: JET-EFDA Contributors. Wed . "Statistical comparison of ICRF and NBI heating performance in JET-ILW L-mode plasmas". United States. doi:10.1063/1.4864531.
@article{osti_22263861,
title = {Statistical comparison of ICRF and NBI heating performance in JET-ILW L-mode plasmas},
author = {Lerche, E. and Van Eester, D. and Jacquet, Ph. and Mayoral, M.-L. and Graham, M. and Matthews, G. and Monakhov, I. and Rimini, F. and Bobkov, V. and Neu, R. and Puetterich, T. and Colas, L. and Czarnecka, A. and Vries, P. de and Collaboration: JET-EFDA Contributors},
abstractNote = {After the change over from the C-wall to the ITER-like Be/W wall (ILW) in JET, the radiation losses during ICRF heating have increased and are now substantially larger than those observed with NBI at the same power levels, in spite of the similar global plasma energies reached with the two heating systems. A comparison of the NBI and ICRF performances in the JET-ILW experiments, based on a statistical analysis of ∼3000 L-mode discharges, will be presented.},
doi = {10.1063/1.4864531},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1580,
place = {United States},
year = {Wed Feb 12 00:00:00 EST 2014},
month = {Wed Feb 12 00:00:00 EST 2014}
}
  • This article 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 achievedmore » 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. Lastly, this reveals that particle fuelling played a key role for achieving high T i/T e, and the improved fusion performance.« less
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  • At ASDEX Upgrade the ECRH system has been upgraded to provide up to 4 MW of heating power at 140 GHz (or 2.2 MW at 105 GHz). The power at 140 GHz exceeds the minimum H-mode power threshold for typical high I{sub p}, B{sub t} conditions by approximately a factor of two. The upgrade allows H-modes with dominant electron heating and significant electron-ion heat exchange to be studied, i.e. the situation expected in ITER. This paper reports on systematic studies varying the heating mix with NBI, ICRF and ECRH and its effect on pedestal parameters and core transport. The H-modemore » pedestal is hardly affected by the choice of heating mix, but the ion temperature in the plasma center is found to vary significantly. The ion channel dominates heat transport and ion temperature gradient modes (ITG) are found to be the most unstable microinstability in all the scenarios considered. R/L{sub Ti} at half radius reduces by a factor of two when T{sub e}/T{sub i} increases from 0.9 to 1.5. TGLF modelling of the electron and ion temperature and electron density profiles shows very good agreement with the experimental data when applying a realistic sawtooth model.« less
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