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The ASDEX upgrade program targeting gaps to fusion energy

Rudolf Neu, Volodymyr Bobkov, Alexander Bock, Matthias Bernert, Marc Beurskens, Albrecht Herrmann, Arne Kallenbach, Peter Thomas Lang, Jean-Marie Noterdaeme UGent, Gabriella Pautasso, et al. (2016) IEEE TRANSACTIONS ON PLASMA SCIENCE. 44(9). p.1472-1480
abstract
Recent experiments in ASDEX Upgrade aimed at improving the physics base for ITER and DEMO to prepare operation and aid the design. In order to increase its exhaust capabilities and operational flexibility, a new bulk W divertor as well as an adjustable cryopump had been installed prior to the 2014 campaign. In experiments with high-field-side pellet injection, central electron densities twice as high as the Greenwald density limit could be achieved without strongly increasing the pedestal density and deleterious effect on confinement. Due to its large installed heating power, a large normalized heat flux P-sep/R = 10 MWm(-1) has been reached, representing two-thirds of the ITER value, under partially detached conditions with a peak target heat flux well below 10 MWm(-2). The divertor load could be further reduced by increasing the core radiation, still keeping the confinement in the range of H-98 y2 approximate to 1. Suppression of edge-localized modes (ELMs) at low collisionality has been observed in a narrow spectral window in contrast to earlier results at high densities. The ITER Q = 10 baseline scenario has been investigated, matching as close as possible the triangularity, the plasma beta, q(95), and the distance to the L-H threshold. It turned out that the ELM frequency is low and consequently the energy ejected by a single ELM is very high and ELM mitigation appears to be difficult. As a possible alternative, a scenario has been developed achieving a similar performance at a lower plasma current (and consequently higher q(95)). Experiments using electron cyclotron current drive (ECCD) with feedback-controlled deposition have allowed successfully testing several control strategies for ITER, including automated control of (3, 2) and (2, 1) neoclassical tearing modes during a single discharge. Concerning advanced scenarios, experiments with central ctr-ECCD have been performed in order to modify the q-profile. A strong reversal of the q-profile could be stationarily achieved and an internal transport barrier could be triggered. In disruption mitigation studies with massive gas injection (MGI), a runaway electron beam could be provoked and mitigated by a second MGI. Ongoing enhancements aim at strengthening the power supplies in order to allow full use of the installed heating power, the exchange of two ion cyclotron resonance heating (ICRH) antennas to reduce the W influx during ICRH, and the upgrading of the electron cyclotron resonance heating (ECRH) system to 7-8 MW for 10 s.
Please use this url to cite or link to this publication:
author
organization
year
type
journalArticle (original)
publication status
published
keyword
Disruptions, plasma scenarios, power exhaust, tokamak
journal title
IEEE TRANSACTIONS ON PLASMA SCIENCE
IEEE Trans. Plasma Sci.
volume
44
issue
9
pages
9 pages
publisher
Ieee-inst Electrical Electronics Engineers Inc
place of publication
Piscataway
conference name
26th Symposium on Fusion Engineering (SOFE) colocated with the 20th Pulsed Power Conference
conference location
Austin, TX
conference start
2015-05-31
conference end
2015-06-04
Web of Science type
Article; Proceedings Paper
Web of Science id
000384231500003
JCR category
PHYSICS, FLUIDS & PLASMAS
JCR impact factor
1.052 (2016)
JCR rank
22/31 (2016)
JCR quartile
3 (2016)
ISSN
0093-3813
1939-9375
DOI
10.1109/TPS.2016.2565567
language
English
UGent publication?
yes
classification
A1
copyright statement
I don't know the status of the copyright for this publication
id
8517467
handle
http://hdl.handle.net/1854/LU-8517467
date created
2017-04-11 10:54:42
date last changed
2017-05-05 07:18:28
@article{8517467,
  abstract     = {Recent experiments in ASDEX Upgrade aimed at improving the physics base for ITER and DEMO to prepare operation and aid the design. In order to increase its exhaust capabilities and operational flexibility, a new bulk W divertor as well as an adjustable cryopump had been installed prior to the 2014 campaign. In experiments with high-field-side pellet injection, central electron densities twice as high as the Greenwald density limit could be achieved without strongly increasing the pedestal density and deleterious effect on confinement. Due to its large installed heating power, a large normalized heat flux P-sep/R = 10 MWm(-1) has been reached, representing two-thirds of the ITER value, under partially detached conditions with a peak target heat flux well below 10 MWm(-2). The divertor load could be further reduced by increasing the core radiation, still keeping the confinement in the range of H-98 y2 approximate to 1. Suppression of edge-localized modes (ELMs) at low collisionality has been observed in a narrow spectral window in contrast to earlier results at high densities. The ITER Q = 10 baseline scenario has been investigated, matching as close as possible the triangularity, the plasma beta, q(95), and the distance to the L-H threshold. It turned out that the ELM frequency is low and consequently the energy ejected by a single ELM is very high and ELM mitigation appears to be difficult. As a possible alternative, a scenario has been developed achieving a similar performance at a lower plasma current (and consequently higher q(95)). Experiments using electron cyclotron current drive (ECCD) with feedback-controlled deposition have allowed successfully testing several control strategies for ITER, including automated control of (3, 2) and (2, 1) neoclassical tearing modes during a single discharge. Concerning advanced scenarios, experiments with central ctr-ECCD have been performed in order to modify the q-profile. A strong reversal of the q-profile could be stationarily achieved and an internal transport barrier could be triggered. In disruption mitigation studies with massive gas injection (MGI), a runaway electron beam could be provoked and mitigated by a second MGI. Ongoing enhancements aim at strengthening the power supplies in order to allow full use of the installed heating power, the exchange of two ion cyclotron resonance heating (ICRH) antennas to reduce the W influx during ICRH, and the upgrading of the electron cyclotron resonance heating (ECRH) system to 7-8 MW for 10 s.},
  author       = {Neu, Rudolf and Bobkov, Volodymyr and Bock, Alexander and Bernert, Matthias and Beurskens, Marc and Herrmann, Albrecht and Kallenbach, Arne and Lang, Peter Thomas and Noterdaeme, Jean-Marie and Pautasso, Gabriella and Reich, Matthias and Schweinzer, Josef and Stober, Joerg and Suttrop, Wolfgang and Zohm, Hartmut and Kirk, Andrew},
  issn         = {0093-3813},
  journal      = {IEEE TRANSACTIONS ON PLASMA SCIENCE},
  keyword      = {Disruptions,plasma scenarios,power exhaust,tokamak},
  language     = {eng},
  location     = {Austin, TX},
  number       = {9},
  pages        = {1472--1480},
  publisher    = {Ieee-inst Electrical Electronics Engineers Inc},
  title        = {The ASDEX upgrade program targeting gaps to fusion energy},
  url          = {http://dx.doi.org/10.1109/TPS.2016.2565567},
  volume       = {44},
  year         = {2016},
}

Chicago
Neu, Rudolf, Volodymyr Bobkov, Alexander Bock, Matthias Bernert, Marc Beurskens, Albrecht Herrmann, Arne Kallenbach, et al. 2016. “The ASDEX Upgrade Program Targeting Gaps to Fusion Energy.” Ieee Transactions on Plasma Science 44 (9): 1472–1480.
APA
Neu, R., Bobkov, V., Bock, A., Bernert, M., Beurskens, M., Herrmann, A., Kallenbach, A., et al. (2016). The ASDEX upgrade program targeting gaps to fusion energy. IEEE TRANSACTIONS ON PLASMA SCIENCE, 44(9), 1472–1480. Presented at the 26th Symposium on Fusion Engineering (SOFE) colocated with the 20th Pulsed Power Conference.
Vancouver
1.
Neu R, Bobkov V, Bock A, Bernert M, Beurskens M, Herrmann A, et al. The ASDEX upgrade program targeting gaps to fusion energy. IEEE TRANSACTIONS ON PLASMA SCIENCE. Piscataway: Ieee-inst Electrical Electronics Engineers Inc; 2016;44(9):1472–80.
MLA
Neu, Rudolf, Volodymyr Bobkov, Alexander Bock, et al. “The ASDEX Upgrade Program Targeting Gaps to Fusion Energy.” IEEE TRANSACTIONS ON PLASMA SCIENCE 44.9 (2016): 1472–1480. Print.