Relationship between locked modes and thermal quenches in DIII-D
Abstract
Locked modes are known to be one of the major causes of disruptions, but the physical mechanisms by which locking leads to disruptions are not well understood. For this study, we analyze the evolution of the temperature profile in the presence of multiple coexisting locked modes during partial and full thermal quenches. Partial quenches are often observed to be an initial, distinct stage in the full thermal quench. Near the onset of partial quenches, locked island O-points are observed to align with each other on the midplane, and their widths are sufficient to overlap each other, as indicated by the Chirikov parameter. Energy conservation analysis of one partial thermal quench shows that the energy lost is both radiated in the divertor region, and conducted or convected to the divertor. Nonlinear resistive magnetohydrodynamic simulations support the interpretation of stochastic fields causing a partial axisymmetric collapse, though the simulated temperature profile exhibits less degradation than the experimental profiles. In discharges with minimum values of the safety factor above ~1.2, locked modes are observed to self-stabilize by inducing, possibly via double tearing modes, a minor disruption that removes their neoclassical drive. These high q min discharges often exhibit relatively low ratios of themore »
- Authors:
-
- Columbia Univ., New York, NY (United States); ITER Organization, St. Paul Lez Durance (France)
- Columbia Univ., New York, NY (United States)
- Univ. of Texas, Austin, TX (United States)
- Univ. of California, San Diego, CA (United States). Center for Energy Research
- Ludwig Maximilian Univ., Munich (Germany)
- General Atomics, San Diego, CA (United States)
- Publication Date:
- Research Org.:
- General Atomics, San Diego, CA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- Contributing Org.:
- The DIII-D Team
- OSTI Identifier:
- 1432050
- Grant/Contract Number:
- FC02-04ER54698; SC0008520; SC0016372; FG02-97ER54415; FG02-04ER54761; FG02-92ER54139
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Nuclear Fusion
- Additional Journal Information:
- Journal Volume: 58; Journal Issue: 5; Journal ID: ISSN 0029-5515
- Publisher:
- IOP Science
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Citation Formats
Sweeney, R., Choi, W., Austin, M., Brookman, M., Izzo, V., Knolker, M., La Haye, R. J., Leonard, A., Strait, E., and Volpe, F. A. Relationship between locked modes and thermal quenches in DIII-D. United States: N. p., 2018.
Web. doi:10.1088/1741-4326/aaaf0a.
Sweeney, R., Choi, W., Austin, M., Brookman, M., Izzo, V., Knolker, M., La Haye, R. J., Leonard, A., Strait, E., & Volpe, F. A. Relationship between locked modes and thermal quenches in DIII-D. United States. https://doi.org/10.1088/1741-4326/aaaf0a
Sweeney, R., Choi, W., Austin, M., Brookman, M., Izzo, V., Knolker, M., La Haye, R. J., Leonard, A., Strait, E., and Volpe, F. A. Wed .
"Relationship between locked modes and thermal quenches in DIII-D". United States. https://doi.org/10.1088/1741-4326/aaaf0a. https://www.osti.gov/servlets/purl/1432050.
@article{osti_1432050,
title = {Relationship between locked modes and thermal quenches in DIII-D},
author = {Sweeney, R. and Choi, W. and Austin, M. and Brookman, M. and Izzo, V. and Knolker, M. and La Haye, R. J. and Leonard, A. and Strait, E. and Volpe, F. A.},
abstractNote = {Locked modes are known to be one of the major causes of disruptions, but the physical mechanisms by which locking leads to disruptions are not well understood. For this study, we analyze the evolution of the temperature profile in the presence of multiple coexisting locked modes during partial and full thermal quenches. Partial quenches are often observed to be an initial, distinct stage in the full thermal quench. Near the onset of partial quenches, locked island O-points are observed to align with each other on the midplane, and their widths are sufficient to overlap each other, as indicated by the Chirikov parameter. Energy conservation analysis of one partial thermal quench shows that the energy lost is both radiated in the divertor region, and conducted or convected to the divertor. Nonlinear resistive magnetohydrodynamic simulations support the interpretation of stochastic fields causing a partial axisymmetric collapse, though the simulated temperature profile exhibits less degradation than the experimental profiles. In discharges with minimum values of the safety factor above ~1.2, locked modes are observed to self-stabilize by inducing, possibly via double tearing modes, a minor disruption that removes their neoclassical drive. These high q min discharges often exhibit relatively low ratios of the plasma internal inductance to the safety factor at 95% of the poloidal flux, which might imply classical stability, in agreement with the decay of the mode when the neoclassical drive is removed.},
doi = {10.1088/1741-4326/aaaf0a},
journal = {Nuclear Fusion},
number = 5,
volume = 58,
place = {United States},
year = {Wed Mar 28 00:00:00 EDT 2018},
month = {Wed Mar 28 00:00:00 EDT 2018}
}
Web of Science
Works referenced in this record:
Experimental Measurements of the Current, Temperature, and Density Profile Changes during a Disruption in the DIII-D Tokamak
journal, February 1996
- Taylor, P. L.; Kellman, A. G.; Rice, B. W.
- Physical Review Letters, Vol. 76, Issue 6
2D tomography with bolometry in DIII‐D a)
journal, February 1995
- Leonard, A. W.; Meyer, W. H.; Geer, B.
- Review of Scientific Instruments, Vol. 66, Issue 2
Avoiding Tokamak Disruptions by Applying Static Magnetic Fields That Align Locked Modes with Stabilizing Wave-Driven Currents
journal, October 2015
- Volpe, F. A.; Hyatt, A.; La Haye, R. J.
- Physical Review Letters, Vol. 115, Issue 17
MHD stable regime of the Tokamak
journal, March 1987
- Cheng, C. Z.; Furth, H. P.; Boozer, A. H.
- Plasma Physics and Controlled Fusion, Vol. 29, Issue 3
Characterization of MHD activity and its influence on radiation asymmetries during massive gas injection in DIII-D
journal, June 2015
- Shiraki, D.; Commaux, N.; Baylor, L. R.
- Nuclear Fusion, Vol. 55, Issue 7
Bifurcated states of a rotating tokamak plasma in the presence of a static error-field
journal, September 1998
- Fitzpatrick, Richard
- Physics of Plasmas, Vol. 5, Issue 9
Nonlinear growth of the tearing mode
journal, January 1973
- Rutherford, P. H.
- Physics of Fluids, Vol. 16, Issue 11
Statistical analysis of m / n = 2/1 locked and quasi-stationary modes with rotating precursors at DIII-D
journal, November 2016
- Sweeney, R.; Choi, W.; La Haye, R. J.
- Nuclear Fusion, Vol. 57, Issue 1
Scaling of the MHD perturbation amplitude required to trigger a disruption and predictions for ITER
journal, December 2015
- de Vries, P. C.; Pautasso, G.; Nardon, E.
- Nuclear Fusion, Vol. 56, Issue 2
A new look at density limits in tokamaks
journal, December 1988
- Greenwald, M.; Terry, J. L.; Wolfe, S. M.
- Nuclear Fusion, Vol. 28, Issue 12
An upgrade of the magnetic diagnostic system of the DIII-D tokamak for non-axisymmetric measurements
journal, August 2014
- King, J. D.; Strait, E. J.; Boivin, R. L.
- Review of Scientific Instruments, Vol. 85, Issue 8
Transport, instability and disruptions in tokamaks
journal, August 1982
- Turner, M. F.; Wesson, J. A.
- Nuclear Fusion, Vol. 22, Issue 8
Plasma stored energy and momentum losses during large MHD activity in JET
journal, February 1990
- Snipes, J. A.; Campbell, D. J.; Hender, T. C.
- Nuclear Fusion, Vol. 30, Issue 2
Simulation of Large Magnetic Islands: A Possible Mechanism for a Major Tokamak Disruption
journal, December 1977
- White, R. B.; Monticello, D. A.; Rosenbluth, M. N.
- Physical Review Letters, Vol. 39, Issue 25
Neoclassical tearing modes and their control
journal, May 2006
- La Haye, R. J.
- Physics of Plasmas, Vol. 13, Issue 5
MHD Equilibrium Reconstruction in the DIII-D Tokamak
journal, October 2005
- Lao, L. L.; John, H. E. St.; Peng, Q.
- Fusion Science and Technology, Vol. 48, Issue 2
Simulations of tokamak disruptions including self-consistent temperature evolution
journal, July 1986
- Bondeson, A.
- Nuclear Fusion, Vol. 26, Issue 7
Major Disruptions in Tokamaks
journal, May 1980
- Sykes, A.; Wesson, J. A.
- Physical Review Letters, Vol. 44, Issue 18
Disruptions in tokamaks
journal, November 1995
- Schuller, F. C.
- Plasma Physics and Controlled Fusion, Vol. 37, Issue 11A
2D/3D electron temperature fluctuations near explosive MHD instabilities accompanied by minor and major disruptions
journal, May 2016
- Choi, M. J.; Park, H. K.; Yun, G. S.
- Nuclear Fusion, Vol. 56, Issue 6
Chapter 3: MHD stability, operational limits and disruptions
journal, June 2007
- Hender, T. C.; Wesley, J. C.; Bialek, J.
- Nuclear Fusion, Vol. 47, Issue 6
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
The NIMROD code: a new approach to numerical plasma physics
journal, January 1999
- Glasser, A. H.; Sovinec, C. R.; Nebel, R. A.
- Plasma Physics and Controlled Fusion, Vol. 41, Issue 3A
MHD instability control, disruptions, and error fields in tokamaks
journal, December 1992
- Morris, A. W.
- Plasma Physics and Controlled Fusion, Vol. 34, Issue 13
Thermal island destabilization and the Greenwald limit
journal, February 2015
- White, R. B.; Gates, D. A.; Brennan, D. P.
- Physics of Plasmas, Vol. 22, Issue 2
Disruptions in JET
journal, April 1989
- Wesson, J. A.; Gill, R. D.; Hugon, M.
- Nuclear Fusion, Vol. 29, Issue 4
Survey of disruption causes at JET
journal, April 2011
- de Vries, P. C.; Johnson, M. F.; Alper, B.
- Nuclear Fusion, Vol. 51, Issue 5
MHD modelling of density limit disruptions in tokamaks
journal, September 1991
- Bondeson, A.; Parker, R. D.; Hugon, M.
- Nuclear Fusion, Vol. 31, Issue 9
Avoidance of tearing mode locking with electro-magnetic torque introduced by feedback-based mode rotation control in DIII-D and RFX-mod
journal, November 2016
- Okabayashi, M.; Zanca, P.; Strait, E. J.
- Nuclear Fusion, Vol. 57, Issue 1
Spatial and temporal analysis of DIII-D 3D magnetic diagnostic data
journal, August 2016
- Strait, E. J.; King, J. D.; Hanson, J. M.
- Review of Scientific Instruments, Vol. 87, Issue 11
A numerical investigation of the effects of impurity penetration depth on disruption mitigation by massive high-pressure gas jet
journal, March 2006
- Izzo, V. A.
- Nuclear Fusion, Vol. 46, Issue 5
Advanced techniques for neoclassical tearing mode control in DIII-D
journal, October 2009
- Volpe, F. A. G.; Austin, M. E.; La Haye, R. J.
- Physics of Plasmas, Vol. 16, Issue 10
Resistive instabilities in general toroidal plasma configurations
journal, January 1975
- Glasser, A. H.; Greene, J. M.; Johnson, J. L.
- Physics of Fluids, Vol. 18, Issue 7
Observation of Nonlinear Neoclassical Pressure-Gradient–Driven Tearing Modes in TFTR
journal, June 1995
- Chang, Z.; Callen, J. D.; Fredrickson, E. D.
- Physical Review Letters, Vol. 74, Issue 23
Effect of a nonuniform resistive wall on the stability of tokamak plasmas
journal, September 1994
- Fitzpatrick, Richard
- Physics of Plasmas, Vol. 1, Issue 9
Neoclassical tearing modes
journal, December 2000
- Buttery, R. J.; Günter, S.; Giruzzi, G.
- Plasma Physics and Controlled Fusion, Vol. 42, Issue 12B
Interaction of tearing modes with external structures in cylindrical geometry (plasma)
journal, July 1993
- Fitzpatrick, R.
- Nuclear Fusion, Vol. 33, Issue 7
Mode locking in tokamaks
journal, December 1990
- Nave, M. F. F.; Wesson, J. A.
- Nuclear Fusion, Vol. 30, Issue 12
Finite-Resistivity Instabilities of a Sheet Pinch
journal, January 1963
- Furth, Harold P.; Killeen, John; Rosenbluth, Marshall N.
- Physics of Fluids, Vol. 6, Issue 4
Resistive wall stabilization of high-beta plasmas in DIII–D
journal, May 2003
- Strait, E. J.; Bialek, J.; Bogatu, N.
- Nuclear Fusion, Vol. 43, Issue 6
Marfe: an edge plasma phenomenon
journal, August 1984
- Lipschultz, B.; LaBombard, B.; Marmar, E. S.
- Nuclear Fusion, Vol. 24, Issue 8
Avoiding Tokamak disruptions by applying static magnetic fields that align locked modes with stabilizing wave-driven currents
text, January 2015
- Volpe, F. A.; Hyatt, A.; La Haye, R. J.
- arXiv
Statistical analysis of $m/n$ = 2/1 locked and quasi-stationary modes with rotating precursors at DIII-D
text, January 2016
- Sweeney, R.; Choi, W.; La Haye, R. J.
- arXiv
Works referencing / citing this record:
Direct measurements of internal structures of born-locked modes and the key role in triggering tokamak disruptions
journal, April 2019
- Du, X. D.; Shafer, M. W.; Hu, Q. M.
- Physics of Plasmas, Vol. 26, Issue 4
Fast and pervasive heat transport induced by multiple locked modes in DIII-D
journal, November 2018
- Hu, Q.; Du, X.; Yu, Q.
- Nuclear Fusion, Vol. 59, Issue 1