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Title: On the very high energy confinement observed in super H-mode DIII-D experiments

Abstract

Analysis of recent super H-mode experiments on DIII-D shows that high rotation, not high pedestal, plays the essential role in achieving very high confinement H 98y2>1.5. Very high confinement is reached early on in the H-mode phase of these discharges, when the pedestal is still very low, but after the toroidal rotation has already built-up to very high levels in the core. As the discharge evolves, the rotation drops, and so does the energy confinement, despite a sustained very high-pressure pedestal. During this evolution, the confinement quality is linearly correlated with the core toroidal rotation, which varies according to different levels of injected neutral beam torque per particle. Core transport modeling shows that the contribution from rotation in the E×B shear is responsible for confinement quality significantly in excess of standard H-mode (H 98y2~1).

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3];  [4];  [2]; ORCiD logo [5]
  1. Oak Ridge Associated Univ., Oak Ridge, TN (United States); Chinese Academy of Sciences (CAS), Beijing (China)
  2. General Atomics, San Diego, CA (United States)
  3. Oak Ridge Associated Univ., Oak Ridge, TN (United States)
  4. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  5. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Publication Date:
Research Org.:
Dept. of Energy (DOE), Washington DC (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
OSTI Identifier:
1594863
Grant/Contract Number:  
FC02-04ER54698
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 60; Journal Issue: 3; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; super H-mode; high thermal energy confinement; toroidal rotation; E×B shear

Citation Formats

Ding, S., Garofalo, A. M., Knolker, M., Marinoni, A., McClenaghan, J., and Grierson, B. A. On the very high energy confinement observed in super H-mode DIII-D experiments. United States: N. p., 2020. Web. doi:10.1088/1741-4326/ab66db.
Ding, S., Garofalo, A. M., Knolker, M., Marinoni, A., McClenaghan, J., & Grierson, B. A. On the very high energy confinement observed in super H-mode DIII-D experiments. United States. doi:10.1088/1741-4326/ab66db.
Ding, S., Garofalo, A. M., Knolker, M., Marinoni, A., McClenaghan, J., and Grierson, B. A. Wed . "On the very high energy confinement observed in super H-mode DIII-D experiments". United States. doi:10.1088/1741-4326/ab66db.
@article{osti_1594863,
title = {On the very high energy confinement observed in super H-mode DIII-D experiments},
author = {Ding, S. and Garofalo, A. M. and Knolker, M. and Marinoni, A. and McClenaghan, J. and Grierson, B. A.},
abstractNote = {Analysis of recent super H-mode experiments on DIII-D shows that high rotation, not high pedestal, plays the essential role in achieving very high confinement H98y2>1.5. Very high confinement is reached early on in the H-mode phase of these discharges, when the pedestal is still very low, but after the toroidal rotation has already built-up to very high levels in the core. As the discharge evolves, the rotation drops, and so does the energy confinement, despite a sustained very high-pressure pedestal. During this evolution, the confinement quality is linearly correlated with the core toroidal rotation, which varies according to different levels of injected neutral beam torque per particle. Core transport modeling shows that the contribution from rotation in the E×B shear is responsible for confinement quality significantly in excess of standard H-mode (H98y2~1).},
doi = {10.1088/1741-4326/ab66db},
journal = {Nuclear Fusion},
number = 3,
volume = 60,
place = {United States},
year = {2020},
month = {1}
}

Journal Article:
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