Impact of drifts on divertor power exhaust in DIII-D

A. E. Jaervinen; S. L. Allen; D. Eldon; M. E. Fenstermacher; M. Groth; D. N. Hill; C. J. Lasnier; A. W. Leonard; A. G. McLean; G. D. Porter; T. D. Rognlien; C. M. Samuell; H. Q. Wang; J. G. Watkins

doi:10.1016/j.nme.2019.02.023

Impact of drifts on divertor power exhaust in DIII-D

A. E. Jaervinen (Corresponding Author), S. L. Allen, D. Eldon, M. E. Fenstermacher, M. Groth, D. N. Hill, C. J. Lasnier, A. W. Leonard, A. G. McLean, G. D. Porter, T. D. Rognlien, C. M. Samuell, H. Q. Wang, J. G. Watkins

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21 Citations (Scopus)

Abstract

Radiative divertor experiments and 2D fluid simulations show strong impact of cross-field drifts on the low field side (LFS) divertor target heat flux and volumetric radiation profiles when evolving to detached conditions in DIII-D high confinement mode (H-mode) plasmas with forward and reversed toroidal field configurations. In both field configurations, the peak heat flux is reduced by about a factor of 2 in detachment by D ₂ -injection and by factor of 3 – 4 in detachment by N ₂ -injection. Operating with the B × ∇B-drift towards the X-point (fwd. BT), the LFS divertor radiation front is observed to shift step-like from the target to near to the X-point at the onset of detachment. In contrast, operating with the B × ∇B-drift away from the X-point (rev. BT), the radiation front is observed to remain closer to the target plate and to be radially shifted towards the far SOL. These phenomena occur with detachment induced both with N ₂ - and D ₂ -injection. The step-like detachment onset is consistent with recently published theory of the role of poloidal E × B-drift in the private flux region in driving highly non-linear detachment onset in fwd. BT [22].

Original language	English
Pages (from-to)	230-238
Number of pages	9
Journal	Nuclear Materials and Energy
Volume	19
DOIs	https://doi.org/10.1016/j.nme.2019.02.023
Publication status	Published - May 2019
MoE publication type	A1 Journal article-refereed

Keywords

Detachment
Divertor
Drifts
Power exhaust
UEDGE

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10.1016/j.nme.2019.02.023

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@article{7aed173e2f3f4410b18ac8e0b722a187,

title = "Impact of drifts on divertor power exhaust in DIII-D",

abstract = " Radiative divertor experiments and 2D fluid simulations show strong impact of cross-field drifts on the low field side (LFS) divertor target heat flux and volumetric radiation profiles when evolving to detached conditions in DIII-D high confinement mode (H-mode) plasmas with forward and reversed toroidal field configurations. In both field configurations, the peak heat flux is reduced by about a factor of 2 in detachment by D 2 -injection and by factor of 3 – 4 in detachment by N 2 -injection. Operating with the B × ∇B-drift towards the X-point (fwd. BT), the LFS divertor radiation front is observed to shift step-like from the target to near to the X-point at the onset of detachment. In contrast, operating with the B × ∇B-drift away from the X-point (rev. BT), the radiation front is observed to remain closer to the target plate and to be radially shifted towards the far SOL. These phenomena occur with detachment induced both with N 2 - and D 2 -injection. The step-like detachment onset is consistent with recently published theory of the role of poloidal E × B-drift in the private flux region in driving highly non-linear detachment onset in fwd. BT [22]. ",

keywords = "Detachment, Divertor, Drifts, Power exhaust, UEDGE",

author = "Jaervinen, {A. E.} and Allen, {S. L.} and D. Eldon and Fenstermacher, {M. E.} and M. Groth and Hill, {D. N.} and Lasnier, {C. J.} and Leonard, {A. W.} and McLean, {A. G.} and Porter, {G. D.} and Rognlien, {T. D.} and Samuell, {C. M.} and Wang, {H. Q.} and Watkins, {J. G.}",

note = "Funding Information: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, using the DIII-D National Fusion Facility, a DOE Office of Science user facility, under AwardsDE-FC02-04ER54698, DE-AC52-07NA27344, and LLNL LDRD project 17-ERD-020. DIII-D data shown in this paper can be obtained in digital format by following the links at https://fusion.gat.com/global/D3D_DMP. Funding Information: This material is based upon work supported by the U.S. Department of Energy, Office of Science , Office of Fusion Energy Sciences, using the DIII-D National Fusion Facility, a DOE Office of Science user facility, under Awards DE-FC02-04ER54698 , DE-AC52-07NA27344 , and LLNL LDRD project 17-ERD-020 . DIII-D data shown in this paper can be obtained in digital format by following the links at https://fusion.gat.com/global/D3D_DMP . Publisher Copyright: {\textcopyright} 2019 The Authors",

year = "2019",

month = may,

doi = "10.1016/j.nme.2019.02.023",

language = "English",

volume = "19",

pages = "230--238",

journal = "Nuclear Materials and Energy",

issn = "2352-1791",

publisher = "Elsevier",

}

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T1 - Impact of drifts on divertor power exhaust in DIII-D

AU - Jaervinen, A. E.

AU - Allen, S. L.

AU - Eldon, D.

AU - Fenstermacher, M. E.

AU - Groth, M.

AU - Hill, D. N.

AU - Lasnier, C. J.

AU - Leonard, A. W.

AU - McLean, A. G.

AU - Porter, G. D.

AU - Rognlien, T. D.

AU - Samuell, C. M.

AU - Wang, H. Q.

AU - Watkins, J. G.

N1 - Funding Information: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, using the DIII-D National Fusion Facility, a DOE Office of Science user facility, under AwardsDE-FC02-04ER54698, DE-AC52-07NA27344, and LLNL LDRD project 17-ERD-020. DIII-D data shown in this paper can be obtained in digital format by following the links at https://fusion.gat.com/global/D3D_DMP. Funding Information: This material is based upon work supported by the U.S. Department of Energy, Office of Science , Office of Fusion Energy Sciences, using the DIII-D National Fusion Facility, a DOE Office of Science user facility, under Awards DE-FC02-04ER54698 , DE-AC52-07NA27344 , and LLNL LDRD project 17-ERD-020 . DIII-D data shown in this paper can be obtained in digital format by following the links at https://fusion.gat.com/global/D3D_DMP . Publisher Copyright: © 2019 The Authors

PY - 2019/5

Y1 - 2019/5

N2 - Radiative divertor experiments and 2D fluid simulations show strong impact of cross-field drifts on the low field side (LFS) divertor target heat flux and volumetric radiation profiles when evolving to detached conditions in DIII-D high confinement mode (H-mode) plasmas with forward and reversed toroidal field configurations. In both field configurations, the peak heat flux is reduced by about a factor of 2 in detachment by D 2 -injection and by factor of 3 – 4 in detachment by N 2 -injection. Operating with the B × ∇B-drift towards the X-point (fwd. BT), the LFS divertor radiation front is observed to shift step-like from the target to near to the X-point at the onset of detachment. In contrast, operating with the B × ∇B-drift away from the X-point (rev. BT), the radiation front is observed to remain closer to the target plate and to be radially shifted towards the far SOL. These phenomena occur with detachment induced both with N 2 - and D 2 -injection. The step-like detachment onset is consistent with recently published theory of the role of poloidal E × B-drift in the private flux region in driving highly non-linear detachment onset in fwd. BT [22].

AB - Radiative divertor experiments and 2D fluid simulations show strong impact of cross-field drifts on the low field side (LFS) divertor target heat flux and volumetric radiation profiles when evolving to detached conditions in DIII-D high confinement mode (H-mode) plasmas with forward and reversed toroidal field configurations. In both field configurations, the peak heat flux is reduced by about a factor of 2 in detachment by D 2 -injection and by factor of 3 – 4 in detachment by N 2 -injection. Operating with the B × ∇B-drift towards the X-point (fwd. BT), the LFS divertor radiation front is observed to shift step-like from the target to near to the X-point at the onset of detachment. In contrast, operating with the B × ∇B-drift away from the X-point (rev. BT), the radiation front is observed to remain closer to the target plate and to be radially shifted towards the far SOL. These phenomena occur with detachment induced both with N 2 - and D 2 -injection. The step-like detachment onset is consistent with recently published theory of the role of poloidal E × B-drift in the private flux region in driving highly non-linear detachment onset in fwd. BT [22].

KW - Detachment

KW - Divertor

KW - Drifts

KW - Power exhaust

KW - UEDGE

UR - http://www.scopus.com/inward/record.url?scp=85062422868&partnerID=8YFLogxK

U2 - 10.1016/j.nme.2019.02.023

DO - 10.1016/j.nme.2019.02.023

M3 - Article

AN - SCOPUS:85062422868

SN - 2352-1791

VL - 19

SP - 230

EP - 238

JO - Nuclear Materials and Energy

JF - Nuclear Materials and Energy

ER -

Impact of drifts on divertor power exhaust in DIII-D

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Keywords

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