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Title: Shafranov shift bifurcation of turbulent transport in the high βp scenario on DIII-D

Abstract

Shafranov shift stabilization of turbulence creates a bifurcation in transport, leading to multiple confinement states in the high βp scenario on DIII-D: an H-mode confinement state with a high edge pedestal, and an enhanced confinement state with a low pedestal and an internal transport barrier (ITB). The bifurcation is observed experimentally in the ion energy transport with respect to mid-radius ( ρ=0.6) pressure gradient. Simultaneously, the electron transport exhibits a similar but less dramatic behavior with respect to pressure gradient. The Shafranov shift is found to increase at the same time as the transition to enhanced confinement, and quasilinear gyro-Landau fluid modeling shows a reduction of predicted energy flux consistent on-set of the ITB. Transient perturbations such as ELMs are likely a trigger for the transition between states by lowering the edge pressure and increasing mid-radius pressure gradient.

Authors:
 [1]; ORCiD logo [1];  [1]; ORCiD logo [2];  [2];  [2]; ORCiD logo [2]
  1. General Atomics, San Diego, CA (United States)
  2. Chinese Academy of Sciences (CAS), Hefei (China)
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:
1569029
Grant/Contract Number:  
FC02-04ER54698; SC0010685
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 59; 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; Shafranov shift; bifurcation; transport; high βρ

Citation Formats

McClenaghan, J., Garofalo, A. M., Staebler, G. M., Ding, S. Y., Gong, X., Qian, J., and Huang, J. Shafranov shift bifurcation of turbulent transport in the high βp scenario on DIII-D. United States: N. p., 2019. Web. doi:10.1088/1741-4326/ab4086.
McClenaghan, J., Garofalo, A. M., Staebler, G. M., Ding, S. Y., Gong, X., Qian, J., & Huang, J. Shafranov shift bifurcation of turbulent transport in the high βp scenario on DIII-D. United States. doi:10.1088/1741-4326/ab4086.
McClenaghan, J., Garofalo, A. M., Staebler, G. M., Ding, S. Y., Gong, X., Qian, J., and Huang, J. Mon . "Shafranov shift bifurcation of turbulent transport in the high βp scenario on DIII-D". United States. doi:10.1088/1741-4326/ab4086.
@article{osti_1569029,
title = {Shafranov shift bifurcation of turbulent transport in the high βp scenario on DIII-D},
author = {McClenaghan, J. and Garofalo, A. M. and Staebler, G. M. and Ding, S. Y. and Gong, X. and Qian, J. and Huang, J.},
abstractNote = {Shafranov shift stabilization of turbulence creates a bifurcation in transport, leading to multiple confinement states in the high βp scenario on DIII-D: an H-mode confinement state with a high edge pedestal, and an enhanced confinement state with a low pedestal and an internal transport barrier (ITB). The bifurcation is observed experimentally in the ion energy transport with respect to mid-radius (ρ=0.6) pressure gradient. Simultaneously, the electron transport exhibits a similar but less dramatic behavior with respect to pressure gradient. The Shafranov shift is found to increase at the same time as the transition to enhanced confinement, and quasilinear gyro-Landau fluid modeling shows a reduction of predicted energy flux consistent on-set of the ITB. Transient perturbations such as ELMs are likely a trigger for the transition between states by lowering the edge pressure and increasing mid-radius pressure gradient.},
doi = {10.1088/1741-4326/ab4086},
journal = {Nuclear Fusion},
number = 12,
volume = 59,
place = {United States},
year = {2019},
month = {9}
}

Journal Article:
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This content will become publicly available on September 2, 2020
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