E × B flow driven electron temperature bifurcation in a closed slot divertor with ion B × ∇B away from the X-point in the DIII-D tokamak
Abstract
An electron temperature bifurcation is observed in the small angle slot divertor, which has been developed to enhance neutral cooling across the divertor target by coupling a closed slot structure with appropriate target shaping. Experiments in the DIII-D tokamak and associated SOLPS-ITER modeling with full drifts find a strong interplay between drifts and divertor geometry on divertor dissipation. The coupling of divertor geometry and drift flows can strongly affect the path towards divertor detachment onset as the plasma density is raised. With the strike point on the inner slanted surface and ion B × ∇B away from the magnetic X-point, bifurcative transitions were observed with sharp decrease of T e towards detachment onset both experimentally and computationally. This differs from the situation for the open divertor where the Te cliff was only observed for ion B × ∇B towards the X-point. SOLPS-ITER modeling with full drifts demonstrates that the magnitude of the E × B drift flow is comparable with the main plasma flow. The reversal of both the poloidal and radial E × B flows near the strike point leads to rapid density accumulation right near the separatrix, which results in bifurcative step transition of divertor conditions with coldmore »
- Authors:
-
[1];
[1];
[1];
[3];
[5];
[6];
[1];
[7];
- General Atomics, San Diego, CA (United States)
- ENN Group, Hebei (China)
- Oak Ridge Associated Univ., Oak Ridge, TN (United States)
- Zap Energy Inc., Seattle, WA (United States)
- Univ. of Tennessee, Knoxville, TN (United States)
- Univ. of Toronto, ON (Canada)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Publication Date:
- Research Org.:
- General Atomics, San Diego, CA (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- OSTI Identifier:
- 1895602
- Alternate Identifier(s):
- OSTI ID: 1898977
- Grant/Contract Number:
- FC02-04ER54698; SC0019256; AC05-00OR22725; NA0003525
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Nuclear Fusion
- Additional Journal Information:
- Journal Volume: 62; Journal Issue: 12; Journal ID: ISSN 0029-5515
- Publisher:
- IOP Science
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; tokamak; divertor physics; drift; SOLLPS-ITER modeling
Citation Formats
Ma, Xinxing, Wang, H. Q., Guo, H. Y., Leonard, A. W., Maurizio, Roberto, Meier, E. T., Ren, Jun, Stangeby, P. C., Sinclair, Greg, Thomas, Daniel M., Wilcox, Robert S., Yu, Jonathan H., and Watkins, J. G. E × B flow driven electron temperature bifurcation in a closed slot divertor with ion B × ∇B away from the X-point in the DIII-D tokamak. United States: N. p., 2022.
Web. doi:10.1088/1741-4326/ac9743.
Ma, Xinxing, Wang, H. Q., Guo, H. Y., Leonard, A. W., Maurizio, Roberto, Meier, E. T., Ren, Jun, Stangeby, P. C., Sinclair, Greg, Thomas, Daniel M., Wilcox, Robert S., Yu, Jonathan H., & Watkins, J. G. E × B flow driven electron temperature bifurcation in a closed slot divertor with ion B × ∇B away from the X-point in the DIII-D tokamak. United States. https://doi.org/10.1088/1741-4326/ac9743
Ma, Xinxing, Wang, H. Q., Guo, H. Y., Leonard, A. W., Maurizio, Roberto, Meier, E. T., Ren, Jun, Stangeby, P. C., Sinclair, Greg, Thomas, Daniel M., Wilcox, Robert S., Yu, Jonathan H., and Watkins, J. G. Mon .
"E × B flow driven electron temperature bifurcation in a closed slot divertor with ion B × ∇B away from the X-point in the DIII-D tokamak". United States. https://doi.org/10.1088/1741-4326/ac9743. https://www.osti.gov/servlets/purl/1895602.
@article{osti_1895602,
title = {E × B flow driven electron temperature bifurcation in a closed slot divertor with ion B × ∇B away from the X-point in the DIII-D tokamak},
author = {Ma, Xinxing and Wang, H. Q. and Guo, H. Y. and Leonard, A. W. and Maurizio, Roberto and Meier, E. T. and Ren, Jun and Stangeby, P. C. and Sinclair, Greg and Thomas, Daniel M. and Wilcox, Robert S. and Yu, Jonathan H. and Watkins, J. G.},
abstractNote = {An electron temperature bifurcation is observed in the small angle slot divertor, which has been developed to enhance neutral cooling across the divertor target by coupling a closed slot structure with appropriate target shaping. Experiments in the DIII-D tokamak and associated SOLPS-ITER modeling with full drifts find a strong interplay between drifts and divertor geometry on divertor dissipation. The coupling of divertor geometry and drift flows can strongly affect the path towards divertor detachment onset as the plasma density is raised. With the strike point on the inner slanted surface and ion B × ∇B away from the magnetic X-point, bifurcative transitions were observed with sharp decrease of T e towards detachment onset both experimentally and computationally. This differs from the situation for the open divertor where the Te cliff was only observed for ion B × ∇B towards the X-point. SOLPS-ITER modeling with full drifts demonstrates that the magnitude of the E × B drift flow is comparable with the main plasma flow. The reversal of both the poloidal and radial E × B flows near the strike point leads to rapid density accumulation right near the separatrix, which results in bifurcative step transition of divertor conditions with cold plasma across the entire divertor target plate. These results indicate that the interplay between geometry and drifts should be fully taken into account in future fusion reactor divertor designs.},
doi = {10.1088/1741-4326/ac9743},
journal = {Nuclear Fusion},
number = 12,
volume = 62,
place = {United States},
year = {Mon Oct 31 00:00:00 EDT 2022},
month = {Mon Oct 31 00:00:00 EDT 2022}
}
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