Direct measurements of internal structures of born-locked modes and the key role in triggering tokamak disruptions

Du, X. D.; Shafer, M. W.; Hu, Q. M.; Evans, T. E.; Strait, E. J.; Ohdachi, S.; Suzuki, Y.

doi:10.1063/1.5085329

Title: Direct measurements of internal structures of born-locked modes and the key role in triggering tokamak disruptions

Abstract

The evolution of the magnetic topology between the outer separatrix of a large m = 2/n = 1 island (m and n: poloidal and toroidal numbers) and the last closed flux surface after mode locking is, for the first time, directly measured. Edge locked island chains with multiple helicity and very narrow widths are discovered to be destabilized and govern the cooling process in the plasma peripheral region. Furthermore, these edge small nonrotating islands are initially well separated from the 2/1 island, leading to a long quasistationary phase, but later trigger thermal quench immediately after they start to overlap with the 2/1 island, producing a broad stochastic layer deep into the plasma midradius.

Authors:

Du, X. D. ^[1]; Shafer, M. W. ^[2];

^[3];

^[1]; Strait, E. J. ^[1]; Ohdachi, S. ^[4];

^[4]

General Atomics, San Diego, CA (United States)
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
National Inst. for Fusion Science, Toki (Japan)

Publication Date:: Mon Apr 15 00:00:00 EDT 2019

Research Org.:: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); General Atomics, San Diego, CA (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

OSTI Identifier:: 1559020

Alternate Identifier(s):: OSTI ID: 1507195; OSTI ID: 1567846; OSTI ID: 1572193; OSTI ID: 1648964

Grant/Contract Number:: AC02-09CH11466; AC05-00OR22725; FC02-04ER54698; SC0015878; AC02- 09CH11466

Resource Type:: Accepted Manuscript

Journal Name:: Physics of Plasmas

Additional Journal Information:: Journal Volume: 26; Journal Issue: 4; 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


                    Du, X. D., Shafer, M. W., Hu, Q. M., Evans, T. E., Strait, E. J., Ohdachi, S., and Suzuki, Y. Direct measurements of internal structures of born-locked modes and the key role in triggering tokamak disruptions.  United States: N. p., 2019. 
Web.  doi:10.1063/1.5085329.

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                    Du, X. D., Shafer, M. W., Hu, Q. M., Evans, T. E., Strait, E. J., Ohdachi, S., & Suzuki, Y. Direct measurements of internal structures of born-locked modes and the key role in triggering tokamak disruptions.  United States.  https://doi.org/10.1063/1.5085329

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                    Du, X. D., Shafer, M. W., Hu, Q. M., Evans, T. E., Strait, E. J., Ohdachi, S., and Suzuki, Y. Mon .  
"Direct measurements of internal structures of born-locked modes and the key role in triggering tokamak disruptions".  United States.  https://doi.org/10.1063/1.5085329.  https://www.osti.gov/servlets/purl/1559020.

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@article{osti_1559020,

  title        = {Direct measurements of internal structures of born-locked modes and the key role in triggering tokamak disruptions},

  author       = {Du, X. D. and Shafer, M. W. and Hu, Q. M. and Evans, T. E. and Strait, E. J. and Ohdachi, S. and Suzuki, Y.},

  abstractNote = {The evolution of the magnetic topology between the outer separatrix of a large m = 2/n = 1 island (m and n: poloidal and toroidal numbers) and the last closed flux surface after mode locking is, for the first time, directly measured. Edge locked island chains with multiple helicity and very narrow widths are discovered to be destabilized and govern the cooling process in the plasma peripheral region. Furthermore, these edge small nonrotating islands are initially well separated from the 2/1 island, leading to a long quasistationary phase, but later trigger thermal quench immediately after they start to overlap with the 2/1 island, producing a broad stochastic layer deep into the plasma midradius.},

  doi          = {10.1063/1.5085329},

  journal      = {Physics of Plasmas},

  number       = 4,

  volume       = 26,

  place        = {United States},

  year         = {Mon Apr 15 00:00:00 EDT 2019},

  month        = {Mon Apr 15 00:00:00 EDT 2019}

}

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Works referenced in this record:

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Tearing mode formation and radiative edge cooling prior to density limit disruptions in ASDEX upgrade
journal, January 1997

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Heat diffusion across a local stochastic magnetic field
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Fast and pervasive heat transport induced by multiple locked modes in DIII-D
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Works referencing / citing this record:

First observation of plasma healing via helical equilibrium in tokamak disruptions
journal, July 2019

Du, X. D.; Shafer, M. W.; Evans, T. E.
Nuclear Fusion, Vol. 59, Issue 9
DOI: 10.1088/1741-4326/ab30bf

27th IAEA Fusion Energy Conference: summary of sessions EX/C, EX/S and PPC
journal, January 2020

Campbell, D. J.
Nuclear Fusion, Vol. 60, Issue 2
DOI: 10.1088/1741-4326/ab5cee

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Title: Direct measurements of internal structures of born-locked modes and the key role in triggering tokamak disruptions

Abstract

Citation Formats

Equilibrium analysis of current profiles in tokamaks journal, June 1990

Relationship between locked modes and thermal quenches in DIII-D journal, March 2018

Plasma response measurements of non-axisymmetric magnetic perturbations on DIII-D via soft x-ray imaginga) journal, December 2014

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

Effect of resonant magnetic perturbations on COMPASS-C tokamak discharges journal, December 1992

Error field experiments in JET journal, April 2000

Critical error fields for locked mode instability in tokamaks journal, March 1992

Nonlinear instability to low m,n=1 error fields in DIII-D as a function of plasma fluid rotation and beta journal, December 1992

Modelling of heat transport in magnetised plasmas using non-aligned coordinates journal, October 2005

Disruptions in JET journal, April 1989

Mode locking in tokamaks journal, December 1990

2D soft x-ray system on DIII-D for imaging the magnetic topology in the pedestal region journal, October 2010

Tearing mode formation and radiative edge cooling prior to density limit disruptions in ASDEX upgrade journal, January 1997

MHD stability and disruption physics in ASDEX Upgrade journal, November 1995

Statistical analysis of m / n = 2/1 locked and quasi-stationary modes with rotating precursors at DIII-D journal, November 2016

Major disruptions induced by helical coils on the Tokoloshe tokamak journal, February 1991

Effect of externally applied resonant magnetic perturbations on resistive tearing modes journal, July 2012

Heat diffusion across a local stochastic magnetic field journal, August 2007

An upgrade of the magnetic diagnostic system of the DIII-D tokamak for non-axisymmetric measurements journal, August 2014

Lack of dependence on resonant error field of locked mode island size in ohmic plasmas in DIII-D journal, January 2015

Fast and pervasive heat transport induced by multiple locked modes in DIII-D journal, November 2018

Statistical analysis of $m/n$ = 2/1 locked and quasi-stationary modes with rotating precursors at DIII-D text, January 2016

First observation of plasma healing via helical equilibrium in tokamak disruptions journal, July 2019

27th IAEA Fusion Energy Conference: summary of sessions EX/C, EX/S and PPC journal, January 2020

Equilibrium analysis of current profiles in tokamaks
journal, June 1990

Relationship between locked modes and thermal quenches in DIII-D
journal, March 2018

Plasma response measurements of non-axisymmetric magnetic perturbations on DIII-D via soft x-ray imaginga)
journal, December 2014

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

Effect of resonant magnetic perturbations on COMPASS-C tokamak discharges
journal, December 1992

Error field experiments in JET
journal, April 2000

Critical error fields for locked mode instability in tokamaks
journal, March 1992

Nonlinear instability to low m,n=1 error fields in DIII-D as a function of plasma fluid rotation and beta
journal, December 1992

Modelling of heat transport in magnetised plasmas using non-aligned coordinates
journal, October 2005

Disruptions in JET
journal, April 1989

Mode locking in tokamaks
journal, December 1990

2D soft x-ray system on DIII-D for imaging the magnetic topology in the pedestal region
journal, October 2010

Tearing mode formation and radiative edge cooling prior to density limit disruptions in ASDEX upgrade
journal, January 1997

MHD stability and disruption physics in ASDEX Upgrade
journal, November 1995

Statistical analysis of m / n = 2/1 locked and quasi-stationary modes with rotating precursors at DIII-D
journal, November 2016

Major disruptions induced by helical coils on the Tokoloshe tokamak
journal, February 1991

Effect of externally applied resonant magnetic perturbations on resistive tearing modes
journal, July 2012

Heat diffusion across a local stochastic magnetic field
journal, August 2007

An upgrade of the magnetic diagnostic system of the DIII-D tokamak for non-axisymmetric measurements
journal, August 2014

Lack of dependence on resonant error field of locked mode island size in ohmic plasmas in DIII-D
journal, January 2015

Fast and pervasive heat transport induced by multiple locked modes in DIII-D
journal, November 2018

Statistical analysis of $m/n$ = 2/1 locked and quasi-stationary modes with rotating precursors at DIII-D
text, January 2016

First observation of plasma healing via helical equilibrium in tokamak disruptions
journal, July 2019

27th IAEA Fusion Energy Conference: summary of sessions EX/C, EX/S and PPC
journal, January 2020