Symmetries and Asymmetries in the Divertor Detachment in ASDEX Upgrade

M. Wischmeier, S. Potzel, Leena Aho-Mantila, M. Bernert, D. Coster, H.-W. Müller, F. Reimold, ASDEX Upgrade Team

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

Abstract

Divertor detachment is a prerequisite for large burning plasma fusion devices. The understanding of the processes leading to divertor detachment is currently incomplete and a reliable prediction for future large scale devices out of reach. In the full-metal ASDEX Upgrade divertor detachment has been studied for Ohmic and L-mode density ramp discharges with deuterium, hydrogen and helium as a fuelling species and both toroidal field directions. For hydrogenic fuelling species the integrated ion flux at the inner target reaches its peak value at an only ∼ 10 - 20% lower ne than for the outer divertor target. However, the maximum of the integrated ion flux to the inner target remains well below what is observed at the outer target.
The numerical transport code package SOLPS5.0 is applied. Under common assumptions for the model it is found that the roll over of the ion flux at the inner and outer targets occurs at a similar ncsep. Contrary to experimental findings the simulated peak values remain comparable for both target plates and no strong reduction of the ion flux density is seen for the inner divertor. An experimental observation of high ne in the far SOL during a fluctuating phase indicates that plasma is transported outward into the far SOL while radiation increases over a large volume. Based on these observations various levels of perpendicular transport in the X-point region of the inner divertor are assumed in the model and impurities are included. The simulated inner target peak ion flux is reduced by a factor of 3 - 4.
Original languageEnglish
Title of host publicationProgramme, Abstracts, Presentations & Proceedings
Subtitle of host publication24th IAEA Fusion Energy Conference, October 8-13, 2012, San Diego, USA
PublisherInternational Atomic Energy Agency IAEA
Number of pages8
Publication statusPublished - 2012
MoE publication typeA4 Article in a conference publication
Event24th IAEA Fusion Energy Conference - San Diego, United States
Duration: 8 Oct 201213 Oct 2012
http://www-naweb.iaea.org/napc/physics/FEC/FEC2012/html/proceedings.pdf (Full proceedings)

Conference

Conference24th IAEA Fusion Energy Conference
CountryUnited States
CitySan Diego
Period8/10/1213/10/12
Internet address

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asymmetry
symmetry
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ramps
deuterium
flux density
fusion
helium
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hydrogen
radiation
predictions
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Cite this

Wischmeier, M., Potzel, S., Aho-Mantila, L., Bernert, M., Coster, D., Müller, H-W., ... Team, ASDEX. U. (2012). Symmetries and Asymmetries in the Divertor Detachment in ASDEX Upgrade. In Programme, Abstracts, Presentations & Proceedings: 24th IAEA Fusion Energy Conference, October 8-13, 2012, San Diego, USA [EX/P5-34] International Atomic Energy Agency IAEA.
Wischmeier, M. ; Potzel, S. ; Aho-Mantila, Leena ; Bernert, M. ; Coster, D. ; Müller, H.-W. ; Reimold, F. ; Team, ASDEX Upgrade. / Symmetries and Asymmetries in the Divertor Detachment in ASDEX Upgrade. Programme, Abstracts, Presentations & Proceedings: 24th IAEA Fusion Energy Conference, October 8-13, 2012, San Diego, USA. International Atomic Energy Agency IAEA, 2012.
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title = "Symmetries and Asymmetries in the Divertor Detachment in ASDEX Upgrade",
abstract = "Divertor detachment is a prerequisite for large burning plasma fusion devices. The understanding of the processes leading to divertor detachment is currently incomplete and a reliable prediction for future large scale devices out of reach. In the full-metal ASDEX Upgrade divertor detachment has been studied for Ohmic and L-mode density ramp discharges with deuterium, hydrogen and helium as a fuelling species and both toroidal field directions. For hydrogenic fuelling species the integrated ion flux at the inner target reaches its peak value at an only ∼ 10 - 20{\%} lower ne than for the outer divertor target. However, the maximum of the integrated ion flux to the inner target remains well below what is observed at the outer target.The numerical transport code package SOLPS5.0 is applied. Under common assumptions for the model it is found that the roll over of the ion flux at the inner and outer targets occurs at a similar ncsep. Contrary to experimental findings the simulated peak values remain comparable for both target plates and no strong reduction of the ion flux density is seen for the inner divertor. An experimental observation of high ne in the far SOL during a fluctuating phase indicates that plasma is transported outward into the far SOL while radiation increases over a large volume. Based on these observations various levels of perpendicular transport in the X-point region of the inner divertor are assumed in the model and impurities are included. The simulated inner target peak ion flux is reduced by a factor of 3 - 4.",
author = "M. Wischmeier and S. Potzel and Leena Aho-Mantila and M. Bernert and D. Coster and H.-W. M{\"u}ller and F. Reimold and Team, {ASDEX Upgrade}",
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Wischmeier, M, Potzel, S, Aho-Mantila, L, Bernert, M, Coster, D, Müller, H-W, Reimold, F & Team, ASDEXU 2012, Symmetries and Asymmetries in the Divertor Detachment in ASDEX Upgrade. in Programme, Abstracts, Presentations & Proceedings: 24th IAEA Fusion Energy Conference, October 8-13, 2012, San Diego, USA., EX/P5-34, International Atomic Energy Agency IAEA, 24th IAEA Fusion Energy Conference, San Diego, United States, 8/10/12.

Symmetries and Asymmetries in the Divertor Detachment in ASDEX Upgrade. / Wischmeier, M.; Potzel, S.; Aho-Mantila, Leena; Bernert, M.; Coster, D.; Müller, H.-W.; Reimold, F.; Team, ASDEX Upgrade.

Programme, Abstracts, Presentations & Proceedings: 24th IAEA Fusion Energy Conference, October 8-13, 2012, San Diego, USA. International Atomic Energy Agency IAEA, 2012. EX/P5-34.

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

TY - GEN

T1 - Symmetries and Asymmetries in the Divertor Detachment in ASDEX Upgrade

AU - Wischmeier, M.

AU - Potzel, S.

AU - Aho-Mantila, Leena

AU - Bernert, M.

AU - Coster, D.

AU - Müller, H.-W.

AU - Reimold, F.

AU - Team, ASDEX Upgrade

PY - 2012

Y1 - 2012

N2 - Divertor detachment is a prerequisite for large burning plasma fusion devices. The understanding of the processes leading to divertor detachment is currently incomplete and a reliable prediction for future large scale devices out of reach. In the full-metal ASDEX Upgrade divertor detachment has been studied for Ohmic and L-mode density ramp discharges with deuterium, hydrogen and helium as a fuelling species and both toroidal field directions. For hydrogenic fuelling species the integrated ion flux at the inner target reaches its peak value at an only ∼ 10 - 20% lower ne than for the outer divertor target. However, the maximum of the integrated ion flux to the inner target remains well below what is observed at the outer target.The numerical transport code package SOLPS5.0 is applied. Under common assumptions for the model it is found that the roll over of the ion flux at the inner and outer targets occurs at a similar ncsep. Contrary to experimental findings the simulated peak values remain comparable for both target plates and no strong reduction of the ion flux density is seen for the inner divertor. An experimental observation of high ne in the far SOL during a fluctuating phase indicates that plasma is transported outward into the far SOL while radiation increases over a large volume. Based on these observations various levels of perpendicular transport in the X-point region of the inner divertor are assumed in the model and impurities are included. The simulated inner target peak ion flux is reduced by a factor of 3 - 4.

AB - Divertor detachment is a prerequisite for large burning plasma fusion devices. The understanding of the processes leading to divertor detachment is currently incomplete and a reliable prediction for future large scale devices out of reach. In the full-metal ASDEX Upgrade divertor detachment has been studied for Ohmic and L-mode density ramp discharges with deuterium, hydrogen and helium as a fuelling species and both toroidal field directions. For hydrogenic fuelling species the integrated ion flux at the inner target reaches its peak value at an only ∼ 10 - 20% lower ne than for the outer divertor target. However, the maximum of the integrated ion flux to the inner target remains well below what is observed at the outer target.The numerical transport code package SOLPS5.0 is applied. Under common assumptions for the model it is found that the roll over of the ion flux at the inner and outer targets occurs at a similar ncsep. Contrary to experimental findings the simulated peak values remain comparable for both target plates and no strong reduction of the ion flux density is seen for the inner divertor. An experimental observation of high ne in the far SOL during a fluctuating phase indicates that plasma is transported outward into the far SOL while radiation increases over a large volume. Based on these observations various levels of perpendicular transport in the X-point region of the inner divertor are assumed in the model and impurities are included. The simulated inner target peak ion flux is reduced by a factor of 3 - 4.

M3 - Conference article in proceedings

BT - Programme, Abstracts, Presentations & Proceedings

PB - International Atomic Energy Agency IAEA

ER -

Wischmeier M, Potzel S, Aho-Mantila L, Bernert M, Coster D, Müller H-W et al. Symmetries and Asymmetries in the Divertor Detachment in ASDEX Upgrade. In Programme, Abstracts, Presentations & Proceedings: 24th IAEA Fusion Energy Conference, October 8-13, 2012, San Diego, USA. International Atomic Energy Agency IAEA. 2012. EX/P5-34