Interaction of external n = 1 magnetic fields with the sawtooth instability in low-q RFX-mod and DIII-D tokamaks
Abstract
External n = 1 magnetic fields are applied in RFX-mod and DIII-D low safety factor Tokamak plasmas to investigate their interaction with the internal MHD dynamics and in particular with the sawtooth instability. In these experiments the applied magnetic fields cause a reduction of both the sawtooth amplitude and period, leading to an overall stabilizing effect on the oscillations. In RFX-mod sawteeth eventually disappear and are replaced by a stationary m = 1, n = 1 helical equilibrium without an increase in disruptivity. However toroidal rotation is significantly reduced in these plasmas, thus it is likely that the sawtooth mitigation in these experiments is due to the combination of the helically deformed core and the reduced rotation. The former effect is qualitatively well reproduced by nonlinear MHD simulations performed with the PIXIE3D code. The results obtained in these RFXmod experiments motivated similar ones in DIII-D L-mode diverted Tokamak plasmas at low q95. These experiments succeeded in reproducing the sawtooth mitigation with the approach developed in RFX-mod. In DIII-D this effect is correlated with a clear increase of the n = 1 plasma response, that indicates an enhancement of the coupling to the marginally stable n = 1 external kink, asmore »
- Authors:
-
- Consorzio RFX (CNR, ENEA, INFN, Univ. di Padova, Acciaierie Venete SpA), Padova (Italy)
- Columbia Univ., New York, NY (United States)
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- General Atomics, San Diego, CA (United States)
- Publication Date:
- Research Org.:
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); General Atomics, San Diego, CA (United States)
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 1335695
- Alternate Identifier(s):
- OSTI ID: 1373937
- Grant/Contract Number:
- FG02-04ER54761; AC02-09CH11466; FC02-04ER54698; 633053
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Nuclear Fusion
- Additional Journal Information:
- Journal Volume: 56; Journal Issue: 10; Journal ID: ISSN 0029-5515
- Publisher:
- IOP Science
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; sawtooth instability; 3D magnetic fields; low-q plasmas
Citation Formats
Piron, C., Martin, P., Bonfiglio, D., Hanson, J., Logan, N. C., Paz-Soldan, C., Piovesan, P., Turco, F., Bialek, J., Franz, P., Jackson, G., Lanctot, M. J., Navratil, G. A., Okabayashi, M., Strait, E., Terranova, D., and Turnbull, A. Interaction of external n = 1 magnetic fields with the sawtooth instability in low-q RFX-mod and DIII-D tokamaks. United States: N. p., 2016.
Web. doi:10.1088/0029-5515/56/10/106012.
Piron, C., Martin, P., Bonfiglio, D., Hanson, J., Logan, N. C., Paz-Soldan, C., Piovesan, P., Turco, F., Bialek, J., Franz, P., Jackson, G., Lanctot, M. J., Navratil, G. A., Okabayashi, M., Strait, E., Terranova, D., & Turnbull, A. Interaction of external n = 1 magnetic fields with the sawtooth instability in low-q RFX-mod and DIII-D tokamaks. United States. https://doi.org/10.1088/0029-5515/56/10/106012
Piron, C., Martin, P., Bonfiglio, D., Hanson, J., Logan, N. C., Paz-Soldan, C., Piovesan, P., Turco, F., Bialek, J., Franz, P., Jackson, G., Lanctot, M. J., Navratil, G. A., Okabayashi, M., Strait, E., Terranova, D., and Turnbull, A. Thu .
"Interaction of external n = 1 magnetic fields with the sawtooth instability in low-q RFX-mod and DIII-D tokamaks". United States. https://doi.org/10.1088/0029-5515/56/10/106012. https://www.osti.gov/servlets/purl/1335695.
@article{osti_1335695,
title = {Interaction of external n = 1 magnetic fields with the sawtooth instability in low-q RFX-mod and DIII-D tokamaks},
author = {Piron, C. and Martin, P. and Bonfiglio, D. and Hanson, J. and Logan, N. C. and Paz-Soldan, C. and Piovesan, P. and Turco, F. and Bialek, J. and Franz, P. and Jackson, G. and Lanctot, M. J. and Navratil, G. A. and Okabayashi, M. and Strait, E. and Terranova, D. and Turnbull, A.},
abstractNote = {External n = 1 magnetic fields are applied in RFX-mod and DIII-D low safety factor Tokamak plasmas to investigate their interaction with the internal MHD dynamics and in particular with the sawtooth instability. In these experiments the applied magnetic fields cause a reduction of both the sawtooth amplitude and period, leading to an overall stabilizing effect on the oscillations. In RFX-mod sawteeth eventually disappear and are replaced by a stationary m = 1, n = 1 helical equilibrium without an increase in disruptivity. However toroidal rotation is significantly reduced in these plasmas, thus it is likely that the sawtooth mitigation in these experiments is due to the combination of the helically deformed core and the reduced rotation. The former effect is qualitatively well reproduced by nonlinear MHD simulations performed with the PIXIE3D code. The results obtained in these RFXmod experiments motivated similar ones in DIII-D L-mode diverted Tokamak plasmas at low q95. These experiments succeeded in reproducing the sawtooth mitigation with the approach developed in RFX-mod. In DIII-D this effect is correlated with a clear increase of the n = 1 plasma response, that indicates an enhancement of the coupling to the marginally stable n = 1 external kink, as simulations with the linear MHD code IPEC suggest. A significant rotation braking in the plasma core is also observed in DIII-D. Numerical calculations of the Neoclassical Toroidal Viscosity (NTV) carried out with PENT identify this torque as a possible contributor for this effect.},
doi = {10.1088/0029-5515/56/10/106012},
journal = {Nuclear Fusion},
number = 10,
volume = 56,
place = {United States},
year = {Thu Aug 11 00:00:00 EDT 2016},
month = {Thu Aug 11 00:00:00 EDT 2016}
}
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Works referenced in this record:
Studies of Internal Disruptions and Oscillations in Tokamak Discharges with Soft—X-Ray Tecniques
journal, November 1974
- von Goeler, S.; Stodiek, W.; Sauthoff, N.
- Physical Review Letters, Vol. 33, Issue 20
Effect of resonant magnetic perturbations on COMPASS-C tokamak discharges
journal, December 1992
- Hender, T. C.; Fitzpatrick, R.; Morris, A. W.
- Nuclear Fusion, Vol. 32, Issue 12
Nonaxisymmetric field effects on Alcator C-Mod
journal, May 2005
- Wolfe, S. M.; Hutchinson, I. H.; Granetz, R. S.
- Physics of Plasmas, Vol. 12, Issue 5
Tearing mode physics studies applying the dynamic ergodic divertor on TEXTOR
journal, November 2006
- Koslowski, H. R.; Westerhof, E.; Bock, M. de
- Plasma Physics and Controlled Fusion, Vol. 48, Issue 12B
Modification of sawtooth crash behaviour during large error field experiments on the DIII-D tokamak
journal, April 1994
- Snider, R. T.; Haye, R. J. La; Turnbull, A. D.
- Nuclear Fusion, Vol. 34, Issue 4
Tokamak Operation with Safety Factor via Control of MHD Stability
journal, July 2014
- Piovesan, P.; Hanson, J. M.; Martin, P.
- Physical Review Letters, Vol. 113, Issue 4
Feedback-assisted extension of the tokamak operating space to low safety factor
journal, July 2014
- Hanson, J. M.; Bialek, J. M.; Baruzzo, M.
- Physics of Plasmas, Vol. 21, Issue 7
An active feedback recovery technique from disruption events induced by m = 2, n = 1 tearing modes in ohmically heated tokamak plasmas
journal, March 2015
- Zanca, P.; Paccagnella, R.; Finotti, C.
- Nuclear Fusion, Vol. 55, Issue 4
New Thomson scattering diagnostic on RFX-mod
journal, January 2007
- Alfier, A.; Pasqualotto, R.
- Review of Scientific Instruments, Vol. 78, Issue 1
An optimized multifoil soft x-ray spectrometer for the determination of the electron temperature with high time resolution
journal, January 1999
- Murari, A.; Franz, P.; Zabeo, L.
- Review of Scientific Instruments, Vol. 70, Issue 1
From distributed to multicore architecture in the RFX-mod real time control system
journal, March 2014
- Manduchi, G.; Luchetta, A.; Soppelsa, A.
- Fusion Engineering and Design, Vol. 89, Issue 3
Tokamak Magnetohydrodynamic Equilibrium States with Axisymmetric Boundary and a 3D Helical Core
journal, July 2010
- Cooper, W. A.; Graves, J. P.; Pochelon, A.
- Physical Review Letters, Vol. 105, Issue 3
An optimal, parallel, fully implicit Newton–Krylov solver for three-dimensional viscoresistive magnetohydrodynamics
journal, May 2008
- Chacón, L.
- Physics of Plasmas, Vol. 15, Issue 5
Nonlinear three-dimensional verification of the SPECYL and PIXIE3D magnetohydrodynamics codes for fusion plasmas
journal, August 2010
- Bonfiglio, D.; Chacón, L.; Cappello, S.
- Physics of Plasmas, Vol. 17, Issue 8
Equilibrium and transport for quasi-helical reversed field pinches
journal, August 2011
- Cappello, S.; Bonfiglio, D.; Escande, D. F.
- Nuclear Fusion, Vol. 51, Issue 10
3D magnetic fields and plasma rotation in RFX-mod tokamak plasmas
journal, September 2013
- Piron, L.; Bonfiglio, D.; Piovesan, P.
- Nuclear Fusion, Vol. 53, Issue 11
Helical self-organization in 3D MHD modelling of fusion plasmas
journal, March 2015
- Bonfiglio, D.; Veranda, M.; Cappello, S.
- Plasma Physics and Controlled Fusion, Vol. 57, Issue 4
Computation of three-dimensional tokamak and spherical torus equilibria
journal, May 2007
- Park, Jong-kyu; Boozer, Allen H.; Glasser, Alan H.
- Physics of Plasmas, Vol. 14, Issue 5
Vacuum calculations in azimuthally symmetric geometry
journal, June 1997
- Chance, M. S.
- Physics of Plasmas, Vol. 4, Issue 6
The importance of matched poloidal spectra to error field correction in DIII-D
journal, July 2014
- Paz-Soldan, C.; Lanctot, M. J.; Logan, N. C.
- Physics of Plasmas, Vol. 21, Issue 7
Neoclassical toroidal viscosity in perturbed equilibria with general tokamak geometry
journal, December 2013
- Logan, Nikolas C.; Park, Jong-Kyu; Kim, Kimin
- Physics of Plasmas, Vol. 20, Issue 12
Validation of the linear ideal magnetohydrodynamic model of three-dimensional tokamak equilibria
journal, March 2010
- Lanctot, M. J.; Reimerdes, H.; Garofalo, A. M.
- Physics of Plasmas, Vol. 17, Issue 3
Wall Stabilization of High Beta Tokamak Discharges in DIII-D
journal, March 1995
- Strait, E. J.; Taylor, T. S.; Turnbull, A. D.
- Physical Review Letters, Vol. 74, Issue 13
Works referencing / citing this record:
Sawtooth oscillation behavior with varying amounts of applied stellarator rotational transform
journal, March 2019
- Herfindal, J. L.; Maurer, D. A.; Hartwell, G. J.
- Physics of Plasmas, Vol. 26, Issue 3
Mitigation of sawtooth crash as a manifestation of MHD mode coupling prior to disruption of KSTAR plasma
journal, March 2019
- Kim, Gnan; Yun, Gunsu S.; Woo, Minho
- Plasma Physics and Controlled Fusion, Vol. 61, Issue 5