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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.:
General Atomics, San Diego, CA (United States); Chinese Academy of Sciences (CAS), Hefei (China)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
OSTI Identifier:
1569029
Grant/Contract Number:  
FC02-04ER54698; SC0010685; 2015GB102002; 2015GB103000
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. https://www.osti.gov/servlets/purl/1569029.
@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}
}

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Works referenced in this record:

Theory of improved confinement in high- beta p tokamaks
journal, September 1994


Transport modeling of the DIII-D high ${{\beta}_{p}}$ scenario and extrapolations to ITER steady-state operation
journal, August 2017


The role of zonal flows in the saturation of multi-scale gyrokinetic turbulence
journal, June 2016

  • Staebler, G. M.; Candy, J.; Howard, N. T.
  • Physics of Plasmas, Vol. 23, Issue 6
  • DOI: 10.1063/1.4954905

Requirements for pellet injection in ITER scenarios with enhanced particle confinement
journal, October 2005


Trapped particle precession in advanced tokamaks
journal, June 1995


Impact of the α parameter on the microstability of internal transport barriers
journal, February 2005


Steady state tokamak reactor based on the bootstrap current
journal, February 1990


Kinetic calculation of neoclassical transport including self-consistent electron and impurity dynamics
journal, July 2008


Confinement improvement in the high poloidal beta regime on DIII-D and application to steady-state H-mode on EAST
journal, May 2017

  • Ding, S.; Garofalo, A. M.; Qian, J.
  • Physics of Plasmas, Vol. 24, Issue 5
  • DOI: 10.1063/1.4982058

New Paradigm for Suppression of Gyrokinetic Turbulence by Velocity Shear
journal, January 2013


Gyrofluid simulations of turbulence suppression in reversed-shear experiments on the Tokamak Fusion Test Reactor
journal, May 1997

  • Beer, M. A.; Hammett, G. W.; Rewoldt, G.
  • Physics of Plasmas, Vol. 4, Issue 5
  • DOI: 10.1063/1.872279

OMFIT Tokamak Profile Data Fitting and Physics Analysis
journal, January 2018


Noncircular, finite aspect ratio, local equilibrium model
journal, April 1998

  • Miller, R. L.; Chu, M. S.; Greene, J. M.
  • Physics of Plasmas, Vol. 5, Issue 4
  • DOI: 10.1063/1.872666

Compatibility of internal transport barrier with steady-state operation in the high bootstrap fraction regime on DIII-D
journal, November 2015


Chapter 6: Steady state operation
journal, June 2007


A theory-based transport model with comprehensive physics
journal, May 2007

  • Staebler, G. M.; Kinsey, J. E.; Waltz, R. E.
  • Physics of Plasmas, Vol. 14, Issue 5
  • DOI: 10.1063/1.2436852

Sustainment of high confinement in JT-60U reversed shear plasmas
journal, February 2002


Roles of Electric Field Shear and Shafranov Shift in Sustaining High Confinement in Enhanced Reversed Shear Plasmas on the TFTR Tokamak
journal, April 1997


Reaching High Poloidal Beta at Greenwald Density with Internal Transport Barrier Close to Full Noninductive Current Drive
journal, August 2001