DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Shrinking of core neoclassical tearing mode magnetic islands due to edge localized modes and the role of ion-scale turbulence in island recovery in DIII-D

Abstract

Experimental signature of long-wavelength turbulence accelerating the recovery of Neoclassical Tearing Mode (NTM) magnetic islands after they have been transiently reduced in size due to inter- action with Edge Localized Modes (ELMs) is reported for the first time. This work shows that per- turbations associated with ELMs result in peaking of the electron temperature (Te) in the O-point region of saturated core m/n 1/4 2/1 islands (m/n being the poloidal/toroidal mode numbers). In syn- chronization with this Te peak, the island width shrinks by as much as 30% suggesting a key role of the Te peak in NTM stability due to modified pressure gradient (rp) and perturbed bootstrap cur- rent (djBS) at the O-point. Next, this Te peak relaxes via anomalous transport (i.e., the diffusivity is 2 orders of magnitude larger than the neoclassical value) and the island recovers. Long-wavelength turbulent density fluctuations (n~) are reduced at the O-point of flat islands but these fluctuations are increased when Te is peaked which offers an explanation for the observed anomalous transport that is responsible for the relaxation of the Te peak. Linear gyrokinetic simulations indicate that n~ inside the peaked island is dominantly driven by the Ion Temperature Gradient instability. Thesemore » measure- ments suggest that n~ accelerates NTM recovery after an ELM crash via accelerating the relaxation of rp at the O-point. These observations are qualitatively replicated by coupled predator-prey equations and modified Rutherford equation. In this simple model, turbulence accelerates NTM recovery via relaxing rp and therefore restoring djBS at the O-point. The key physics of the rela- tionship between the Te peak and NTM stability has potentially far-reaching consequences, such as NTM control via pellet injection in high-b tokamak plasmas.« less

Authors:
 [1];  [1]; ORCiD logo [1];  [2]; ORCiD logo [1];  [3]
  1. Univ. of California, Los Angeles, CA (United States)
  2. General Atomics, San Diego, CA (United States)
  3. Univ. of Wisconsin, Madison, WI (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1361640
Alternate Identifier(s):
OSTI ID: 1361924
Grant/Contract Number:  
AC02-05CH11231; FC02-04ER54698; FG03-86ER53266; FG02-08ER54984
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 6; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Bardóczi, Laszlo, Rhodes, Terry L., Carter, Troy A., La Haye, Robert J., Bañón Navarro, Alejandro, and McKee, George R. Shrinking of core neoclassical tearing mode magnetic islands due to edge localized modes and the role of ion-scale turbulence in island recovery in DIII-D. United States: N. p., 2017. Web. doi:10.1063/1.4985078.
Bardóczi, Laszlo, Rhodes, Terry L., Carter, Troy A., La Haye, Robert J., Bañón Navarro, Alejandro, & McKee, George R. Shrinking of core neoclassical tearing mode magnetic islands due to edge localized modes and the role of ion-scale turbulence in island recovery in DIII-D. United States. https://doi.org/10.1063/1.4985078
Bardóczi, Laszlo, Rhodes, Terry L., Carter, Troy A., La Haye, Robert J., Bañón Navarro, Alejandro, and McKee, George R. Thu . "Shrinking of core neoclassical tearing mode magnetic islands due to edge localized modes and the role of ion-scale turbulence in island recovery in DIII-D". United States. https://doi.org/10.1063/1.4985078. https://www.osti.gov/servlets/purl/1361640.
@article{osti_1361640,
title = {Shrinking of core neoclassical tearing mode magnetic islands due to edge localized modes and the role of ion-scale turbulence in island recovery in DIII-D},
author = {Bardóczi, Laszlo and Rhodes, Terry L. and Carter, Troy A. and La Haye, Robert J. and Bañón Navarro, Alejandro and McKee, George R.},
abstractNote = {Experimental signature of long-wavelength turbulence accelerating the recovery of Neoclassical Tearing Mode (NTM) magnetic islands after they have been transiently reduced in size due to inter- action with Edge Localized Modes (ELMs) is reported for the first time. This work shows that per- turbations associated with ELMs result in peaking of the electron temperature (Te) in the O-point region of saturated core m/n 1/4 2/1 islands (m/n being the poloidal/toroidal mode numbers). In syn- chronization with this Te peak, the island width shrinks by as much as 30% suggesting a key role of the Te peak in NTM stability due to modified pressure gradient (rp) and perturbed bootstrap cur- rent (djBS) at the O-point. Next, this Te peak relaxes via anomalous transport (i.e., the diffusivity is 2 orders of magnitude larger than the neoclassical value) and the island recovers. Long-wavelength turbulent density fluctuations (n~) are reduced at the O-point of flat islands but these fluctuations are increased when Te is peaked which offers an explanation for the observed anomalous transport that is responsible for the relaxation of the Te peak. Linear gyrokinetic simulations indicate that n~ inside the peaked island is dominantly driven by the Ion Temperature Gradient instability. These measure- ments suggest that n~ accelerates NTM recovery after an ELM crash via accelerating the relaxation of rp at the O-point. These observations are qualitatively replicated by coupled predator-prey equations and modified Rutherford equation. In this simple model, turbulence accelerates NTM recovery via relaxing rp and therefore restoring djBS at the O-point. The key physics of the rela- tionship between the Te peak and NTM stability has potentially far-reaching consequences, such as NTM control via pellet injection in high-b tokamak plasmas.},
doi = {10.1063/1.4985078},
journal = {Physics of Plasmas},
number = 6,
volume = 24,
place = {United States},
year = {Thu Jun 08 00:00:00 EDT 2017},
month = {Thu Jun 08 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 17 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

The beam emission spectroscopy diagnostic on the DIII-D tokamak
journal, January 1999

  • McKee, G.; Ashley, R.; Durst, R.
  • Review of Scientific Instruments, Vol. 70, Issue 1
  • DOI: 10.1063/1.1149416

Experimental confirmation of self-regulating turbulence paradigm in two-dimensional spectral condensation
journal, December 2014


Magnetic-Flux Pumping in High-Performance, Stationary Plasmas with Tearing Modes
journal, January 2009


Electron cyclotron emission radiometer upgrade on the DIII-D tokamak
journal, March 2003

  • Austin, M. E.; Lohr, J.
  • Review of Scientific Instruments, Vol. 74, Issue 3
  • DOI: 10.1063/1.1530387

Observation of a Critical Gradient Threshold for Electron Temperature Fluctuations in the DIII-D Tokamak
journal, January 2013


Helical temperature perturbations associated with tearing modes in tokamak plasmas
journal, March 1995

  • Fitzpatrick, Richard
  • Physics of Plasmas, Vol. 2, Issue 3
  • DOI: 10.1063/1.871434

Multi-field/-scale interactions of turbulence with neoclassical tearing mode magnetic islands in the DIII-D tokamak
journal, May 2017

  • Bardóczi, L.; Rhodes, T. L.; Bañón Navarro, A.
  • Physics of Plasmas, Vol. 24, Issue 5
  • DOI: 10.1063/1.4977533

The nonlinear coupling between gyroradius scale turbulence and mesoscale magnetic islands in fusion plasmas
journal, September 2010

  • Hornsby, W. A.; Peeters, A. G.; Snodin, A. P.
  • Physics of Plasmas, Vol. 17, Issue 9
  • DOI: 10.1063/1.3467502

Beta limits in long-pulse tokamak discharges
journal, May 1997

  • Sauter, O.; La Haye, R. J.; Chang, Z.
  • Physics of Plasmas, Vol. 4, Issue 5
  • DOI: 10.1063/1.872270

Improved charge-coupled device detectors for high-speed, charge exchange spectroscopy studies on the DIII-D tokamak
journal, October 2004

  • Burrell, K. H.; Gohil, P.; Groebner, R. J.
  • Review of Scientific Instruments, Vol. 75, Issue 10
  • DOI: 10.1063/1.1787949

Electron temperature gradient driven turbulence
journal, May 2000

  • Jenko, F.; Dorland, W.; Kotschenreuther, M.
  • Physics of Plasmas, Vol. 7, Issue 5
  • DOI: 10.1063/1.874014

Comparison of Pseudospectral and Spectral Approximation
journal, September 1972


Effects of magnetic islands on bootstrap current in toroidal plasmas
journal, December 2016


Modulation of Core Turbulent Density Fluctuations by Large-Scale Neoclassical Tearing Mode Islands in the DIII-D Tokamak
journal, May 2016


Fiber optic two-color vibration compensated interferometer for plasma density measurements
journal, October 2006

  • Van Zeeland, M. A.; Boivin, R. L.; Carlstrom, T. N.
  • Review of Scientific Instruments, Vol. 77, Issue 10
  • DOI: 10.1063/1.2336437

The role of asymmetries in the growth and suppression of neoclassical tearing modes
journal, February 2011


Behaviour of turbulent transport in the vicinity of a magnetic island
journal, May 2009


On seed island generation and the non-linear self-consistent interaction of the tearing mode With electromagnetic gyro-kinetic turbulence
journal, April 2015


A design retrospective of the DIII-D tokamak
journal, May 2002


Observation of Reduced Heat Transport inside the Magnetic Island O Point in the Large Helical Device
journal, February 2004


Control of magnetic islands by pellet injection in tokamaks
journal, July 2007

  • Shaing, K. C.; Houlberg, W. A.; Peng, M.
  • Physics of Plasmas, Vol. 14, Issue 7
  • DOI: 10.1063/1.2743516

Role of Zonal Flow Predator-Prey Oscillations in Triggering the Transition to H-Mode Confinement
journal, April 2012


The influence of finite radial transport on the structure and evolution of m / n = 2/1 neoclassical tearing modes on MAST
journal, May 2012


Millimeter-wave backscatter diagnostic for the study of short scale length plasma fluctuations (invited)
journal, October 2006

  • Rhodes, T. L.; Peebles, W. A.; Nguyen, X.
  • Review of Scientific Instruments, Vol. 77, Issue 10
  • DOI: 10.1063/1.2235874

Spectrally Condensed Fluid Turbulence and L-H Transitions in Plasma
journal, January 2009


Effect of magnetic islands on profiles, flows, turbulence and transport in nonlinear gyrokinetic simulations
journal, February 2017

  • Navarro, A. Bañón; Bardóczi, L.; Carter, T. A.
  • Plasma Physics and Controlled Fusion, Vol. 59, Issue 3
  • DOI: 10.1088/1361-6587/aa557e

Analysis of the structure of neoclassical tearing modes in ASDEX Upgrade
journal, September 2001


Hybrid-like 2/1 flux-pumping and magnetic island evolution due to edge localized mode-neoclassical tearing mode coupling in DIII-D
journal, February 2012

  • King, J. D.; La Haye, R. J.; Petty, C. C.
  • Physics of Plasmas, Vol. 19, Issue 2
  • DOI: 10.1063/1.3684648

Reduction of Ion Thermal Diffusivity Inside a Magnetic Island in JT-60U Tokamak Plasma
journal, August 2012


Zonal Flows and Transient Dynamics of the L H Transition
journal, May 2003


Island bootstrap current modification of the nonlinear dynamics of the tearing mode
journal, January 1986

  • Carrera, R.; Hazeltine, R. D.; Kotschenreuther, M.
  • Physics of Fluids, Vol. 29, Issue 4
  • DOI: 10.1063/1.865682

Measuring Δ′ from electron temperature fluctuations in the Tokamak Fusion Test Reactor
journal, February 1998

  • Ren, C.; Callen, J. D.; Gianakon, T. A.
  • Physics of Plasmas, Vol. 5, Issue 2
  • DOI: 10.1063/1.872729

Electron profile stiffness and critical gradient studies
journal, August 2012

  • DeBoo, J. C.; Petty, C. C.; White, A. E.
  • Physics of Plasmas, Vol. 19, Issue 8
  • DOI: 10.1063/1.4750061

Works referencing / citing this record:

Impact of neoclassical tearing mode–turbulence multi-scale interaction in global confinement degradation and magnetic island stability
journal, December 2017

  • Bardóczi, L.; Carter, T. A.; La Haye, R. J.
  • Physics of Plasmas, Vol. 24, Issue 12
  • DOI: 10.1063/1.5004987

Gyrokinetic simulation study of magnetic island effects on neoclassical physics and micro-instabilities in a realistic KSTAR plasma
journal, May 2018

  • Kwon, Jae-Min; Ku, S.; Choi, M. J.
  • Physics of Plasmas, Vol. 25, Issue 5
  • DOI: 10.1063/1.5027622

Intrinsic current driven by electromagnetic electron drift wave turbulence in the tokamak pedestal region
journal, October 2019


On the interplay between MHD instabilities and turbulent transport in magnetically confined plasmas
journal, October 2019


Interaction of magnetic islands with turbulent electron temperature fluctuations in DIII-D and in GENE nonlinear gyrokinetic simulations
journal, December 2019

  • Bardóczi, L.; Sung, C.; Navarro, A. Bañón
  • Plasma Physics and Controlled Fusion, Vol. 62, Issue 2
  • DOI: 10.1088/1361-6587/ab5c69

A mechanism of neoclassical tearing modes onset by drift wave turbulence
journal, December 2018


Multi-scale interaction of pedestal instabilities in H-mode plasma on the EAST tokamak
journal, April 2019


Gyrokinetic simulations of nonlinear interactions between magnetic islands and microturbulence
journal, September 2019

  • Fang, Kaisheng; Bao, Jian; Lin, Zhihong
  • Plasma Science and Technology, Vol. 21, Issue 11
  • DOI: 10.1088/2058-6272/ab3c83