H-mode grade confinement in L-mode edge plasmas at negative triangularity on DIII-D

Plasmas with a negative triangularity shape have been created on the DIII-D tokamak that, despite maintaining standard L-mode edge radial profiles, reach volume averaged pressure levels typical of H-mode scenarios. Within the auxiliary power available for these experiments, plasmas exhibit near-zero power degradation while sustaining beta(N) = 2.7 and H-98,H-y2 = 1.2 for several energy confinement times. Detailed comparison with matched discharges at positive triangularity indicates that Trapped Electron Modes are weakened at negative triangularity, consistent with increased confinement and reduced intensity of fluctuations in electron density, electron temperature, and ion density. These results indicate that a negative triangularity plasma operating without an edge pedestal might provide an attractive scenario for operations in future reactors. Published under license by AIP Publishing.


Published in:
Physics Of Plasmas, 26, 4, 042515
Presented at:
60th Annual Meeting of the APS-Division-of-Plasma-Physics Co-Located with the 71st Annual Gaseous Electronics Conference, Portland, OR, Nov 05-09, 2018
Year:
Apr 01 2019
Publisher:
Melville, AMER INST PHYSICS
ISSN:
1070-664X
1089-7674
Keywords:




 Record created 2019-06-18, last modified 2019-06-30


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