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Title: Attainment of a stable, fully detached plasma state in innovative divertor configurations

Abstract

A computational study of long-legged tokamak divertor configurations is performed with the edge transport code UEDGE. Several divertor configurations are considered, with radially or vertically extended, tightly baffled, outer divertor legs and with or without a secondary X-point in the divertor leg volume. For otherwise identical conditions, a scan of the input power from the core plasma is performed. As the power is reduced to a threshold value, the plasma in the outer leg transitions to a fully detached state, which defines the upper limit on the power for detached divertor operation. Reducing the power further results in the detachment front shifting upstream but remains stable. At low power, the detachment front eventually moves all the way to the primary X-point, which is usually associated with degradation of the core plasma, and this defines the lower limit on the power for the detached divertor operation. For the studied parameters, for long-legged divertors, the detached operation window is quite large, in particular, for the X-point target configuration using a secondary X-point in the divertor leg volume, allowing a factor of 5–10 variations in the input power. For the same parameters, for the standard divertor configuration, the detached operation window is verymore » small or even non-existent. In conclusion, the present modeling results suggest the possibility of stable fully detached divertor operation for a tokamak with tightly baffled extended divertor legs.« less

Authors:
 [1];  [2];  [2];  [1];  [1]; ORCiD logo [2];  [2]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. MIT Plasma Science and Fusion Center, Cambridge, MA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1461739
Alternate Identifier(s):
OSTI ID: 1373961
Report Number(s):
LLNL-JRNL-712618
Journal ID: ISSN 1070-664X; 850966; TRN: US1902034
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Umansky, M. V., LaBombard, B., Brunner, D., Rensink, M. E., Rognlien, T. D., Terry, J. L., and Whyte, D. G. Attainment of a stable, fully detached plasma state in innovative divertor configurations. United States: N. p., 2017. Web. doi:10.1063/1.4979193.
Umansky, M. V., LaBombard, B., Brunner, D., Rensink, M. E., Rognlien, T. D., Terry, J. L., & Whyte, D. G. Attainment of a stable, fully detached plasma state in innovative divertor configurations. United States. https://doi.org/10.1063/1.4979193
Umansky, M. V., LaBombard, B., Brunner, D., Rensink, M. E., Rognlien, T. D., Terry, J. L., and Whyte, D. G. Tue . "Attainment of a stable, fully detached plasma state in innovative divertor configurations". United States. https://doi.org/10.1063/1.4979193. https://www.osti.gov/servlets/purl/1461739.
@article{osti_1461739,
title = {Attainment of a stable, fully detached plasma state in innovative divertor configurations},
author = {Umansky, M. V. and LaBombard, B. and Brunner, D. and Rensink, M. E. and Rognlien, T. D. and Terry, J. L. and Whyte, D. G.},
abstractNote = {A computational study of long-legged tokamak divertor configurations is performed with the edge transport code UEDGE. Several divertor configurations are considered, with radially or vertically extended, tightly baffled, outer divertor legs and with or without a secondary X-point in the divertor leg volume. For otherwise identical conditions, a scan of the input power from the core plasma is performed. As the power is reduced to a threshold value, the plasma in the outer leg transitions to a fully detached state, which defines the upper limit on the power for detached divertor operation. Reducing the power further results in the detachment front shifting upstream but remains stable. At low power, the detachment front eventually moves all the way to the primary X-point, which is usually associated with degradation of the core plasma, and this defines the lower limit on the power for the detached divertor operation. For the studied parameters, for long-legged divertors, the detached operation window is quite large, in particular, for the X-point target configuration using a secondary X-point in the divertor leg volume, allowing a factor of 5–10 variations in the input power. For the same parameters, for the standard divertor configuration, the detached operation window is very small or even non-existent. In conclusion, the present modeling results suggest the possibility of stable fully detached divertor operation for a tokamak with tightly baffled extended divertor legs.},
doi = {10.1063/1.4979193},
journal = {Physics of Plasmas},
number = 5,
volume = 24,
place = {United States},
year = {Tue Mar 28 00:00:00 EDT 2017},
month = {Tue Mar 28 00:00:00 EDT 2017}
}

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Cited by: 11 works
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Works referencing / citing this record:

UEDGE modelling of detached divertor operation for long-leg divertor geometries in ARC
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Radiative heat exhaust in Alcator C-Mod I-mode plasmas
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Performance assessment of long-legged tightly-baffled divertor geometries in the ARC reactor concept
journal, September 2019


Study of passively stable, fully detached divertor plasma regimes attained in innovative long-legged divertor configurations
journal, October 2019