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

Title: Impact of toroidal and poloidal mode spectra on the control of non-axisymmetric fields in tokamaks

Abstract

In several tokamaks, non-axisymmetric magnetic field studies show that applied magnetic fields with a toroidal harmonic n = 2 can lead to disruptive n = 1 locked modes. In Ohmic plasmas, n = 2 magnetic reconnection thresholds in otherwise stable discharges are readily accessed at edge safety factors q ~ 3, low density, and low rotation. Similar to previous studies with n = 1 fields, the thresholds are correlated with the “overlap” field computed with the IPEC code. The overlap field quantifies the plasma-mediated coupling of the external field to the resonant field. Remarkably, the “critical overlap fields” at which magnetic islands form are similar for applied n =1 and 2 fields. The critical overlap field increases with plasma density and edge safety factor but is independent of the toroidal field. Poloidal harmonics m > nq dominate the drive for resonant fields while m < nq harmonics have a negligible impact. This contrasts with previous results in H-mode discharges at high plasma pressure in which the toroidal angular momentum is sensitive to low poloidal harmonics. Altogether, these results highlight unique requirements for n > 1 field control including the need for multiple rows of coils to control selected plasma parametersmore » for specific functions (e.g., rotation control or ELM suppression).« less

Authors:
ORCiD logo [1];  [2];  [3];  [4];  [5];  [6];  [2];  [7]; ORCiD logo [2];  [8];  [8];  [5];  [2];  [9];  [10];  [5];  [4];  [5]
  1. General Atomics, San Diego, CA (United States); U.S. Dept. of Energy, Washington, D.C. (United States)
  2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  3. Univ. di Padova, Padova (Italy)
  4. Chinese Academy of Sciences, Hefei (People's Republic of China)
  5. General Atomics, San Diego, CA (United States)
  6. KTH Royal Institute of Technology, Stockholm (Sweden)
  7. Columbia Univ., New York, NY (United States)
  8. National Fusion Research Institute, Daejeon (South Korea)
  9. Consorzio RFX, EURATOM-ENEA Assoc., Padova (Italy)
  10. Univ. of California San Diego, La Jolla, CA (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE
Contributing Org.:
JET Contributors
OSTI Identifier:
1373416
Alternate Identifier(s):
OSTI ID: 1361859
Grant/Contract Number:  
FC02-04ER54698; AC02-09CH11466; FG02-04ER54761; FG02-05ER54809
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 5; 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

Lanctot, Matthew J., Park, J. -K., Piovesan, Paolo, Sun, Y., Buttery, Richard J., Frassinetti, L., Grierson, Brian A., Hanson, Jeremy M., Haskey, Shaun R., In, Y., Jeon, Y. M., La Haye, Robert J., Logan, N. C., Marrelli, L., Orlov, Dmitry M., Paz-Soldan, Carlos, Wang, H. H., and Strait, Edward J. Impact of toroidal and poloidal mode spectra on the control of non-axisymmetric fields in tokamaks. United States: N. p., 2017. Web. doi:10.1063/1.4982688.
Lanctot, Matthew J., Park, J. -K., Piovesan, Paolo, Sun, Y., Buttery, Richard J., Frassinetti, L., Grierson, Brian A., Hanson, Jeremy M., Haskey, Shaun R., In, Y., Jeon, Y. M., La Haye, Robert J., Logan, N. C., Marrelli, L., Orlov, Dmitry M., Paz-Soldan, Carlos, Wang, H. H., & Strait, Edward J. Impact of toroidal and poloidal mode spectra on the control of non-axisymmetric fields in tokamaks. United States. https://doi.org/10.1063/1.4982688
Lanctot, Matthew J., Park, J. -K., Piovesan, Paolo, Sun, Y., Buttery, Richard J., Frassinetti, L., Grierson, Brian A., Hanson, Jeremy M., Haskey, Shaun R., In, Y., Jeon, Y. M., La Haye, Robert J., Logan, N. C., Marrelli, L., Orlov, Dmitry M., Paz-Soldan, Carlos, Wang, H. H., and Strait, Edward J. Thu . "Impact of toroidal and poloidal mode spectra on the control of non-axisymmetric fields in tokamaks". United States. https://doi.org/10.1063/1.4982688. https://www.osti.gov/servlets/purl/1373416.
@article{osti_1373416,
title = {Impact of toroidal and poloidal mode spectra on the control of non-axisymmetric fields in tokamaks},
author = {Lanctot, Matthew J. and Park, J. -K. and Piovesan, Paolo and Sun, Y. and Buttery, Richard J. and Frassinetti, L. and Grierson, Brian A. and Hanson, Jeremy M. and Haskey, Shaun R. and In, Y. and Jeon, Y. M. and La Haye, Robert J. and Logan, N. C. and Marrelli, L. and Orlov, Dmitry M. and Paz-Soldan, Carlos and Wang, H. H. and Strait, Edward J.},
abstractNote = {In several tokamaks, non-axisymmetric magnetic field studies show that applied magnetic fields with a toroidal harmonic n = 2 can lead to disruptive n = 1 locked modes. In Ohmic plasmas, n = 2 magnetic reconnection thresholds in otherwise stable discharges are readily accessed at edge safety factors q ~ 3, low density, and low rotation. Similar to previous studies with n = 1 fields, the thresholds are correlated with the “overlap” field computed with the IPEC code. The overlap field quantifies the plasma-mediated coupling of the external field to the resonant field. Remarkably, the “critical overlap fields” at which magnetic islands form are similar for applied n =1 and 2 fields. The critical overlap field increases with plasma density and edge safety factor but is independent of the toroidal field. Poloidal harmonics m > nq dominate the drive for resonant fields while m < nq harmonics have a negligible impact. This contrasts with previous results in H-mode discharges at high plasma pressure in which the toroidal angular momentum is sensitive to low poloidal harmonics. Altogether, these results highlight unique requirements for n > 1 field control including the need for multiple rows of coils to control selected plasma parameters for specific functions (e.g., rotation control or ELM suppression).},
doi = {10.1063/1.4982688},
journal = {Physics of Plasmas},
number = 5,
volume = 24,
place = {United States},
year = {Thu May 18 00:00:00 EDT 2017},
month = {Thu May 18 00:00:00 EDT 2017}
}

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

Citation Metrics:
Cited by: 16 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Suppression of Edge Localized Modes in High-Confinement KSTAR Plasmas by Nonaxisymmetric Magnetic Perturbations
journal, July 2012


Error field correction in DIII-D Ohmic plasmas with either handedness
journal, January 2011


Dependence of neoclassical toroidal viscosity on the poloidal spectrum of applied nonaxisymmetric fields
journal, February 2016


Neoclassical transport fluxes in the plateau regime in nonaxisymmetric toroidal plasmas
journal, January 1986

  • Shaing, K. C.; Hirshman, S. P.; Callen, J. D.
  • Physics of Fluids, Vol. 29, Issue 2
  • DOI: 10.1063/1.865439

Effect of Neoclassical Toroidal Viscosity on Error-Field Penetration Thresholds in Tokamak Plasmas
journal, August 2007


Multi-channel transport experiments at Alcator C-Mod and comparison with gyrokinetic simulations
journal, May 2013

  • White, A. E.; Howard, N. T.; Greenwald, M.
  • Physics of Plasmas, Vol. 20, Issue 5
  • DOI: 10.1063/1.4803089

Stabilization of the external kink and the resistive wall mode
journal, October 2010


Resonant magnetic perturbations of edge-plasmas in toroidal confinement devices
journal, November 2015


Perturbed plasma equilibria
journal, October 2006

  • Boozer, Allen H.; Nührenberg, Carolin
  • Physics of Plasmas, Vol. 13, Issue 10
  • DOI: 10.1063/1.2353903

Multi-mode error field correction on the DIII-D tokamak
journal, March 2003


Decoupled recovery of energy and momentum with correction of n   =  2 error fields
journal, July 2015


Overview of the RFX-mod fusion science programme
journal, September 2013


Measurement of deuterium density profiles in the H-mode steep gradient region using charge exchange recombination spectroscopy on DIII-D
journal, September 2016

  • Haskey, S. R.; Grierson, B. A.; Burrell, K. H.
  • Review of Scientific Instruments, Vol. 87, Issue 11
  • DOI: 10.1063/1.4963148

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
  • DOI: 10.1063/1.4886795

Rotation and momentum transport in tokamaks and helical systems
journal, March 2014


Error field mode studies on JET, COMPASS-D and DIII-D, and implications for ITER
journal, November 1999


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

  • La Haye, R. J.; Fitzpatrick, R.; Hender, T. C.
  • Physics of Fluids B: Plasma Physics, Vol. 4, Issue 7
  • DOI: 10.1063/1.860017

First Observation of Edge Localized Modes Mitigation with Resonant and Nonresonant Magnetic Perturbations in ASDEX Upgrade
journal, June 2011


Active spectroscopic measurements of the bulk deuterium properties in the DIII-D tokamak (invited)
journal, October 2012

  • Grierson, B. A.; Burrell, K. H.; Chrystal, C.
  • Review of Scientific Instruments, Vol. 83, Issue 10
  • DOI: 10.1063/1.4739239

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
  • DOI: 10.1063/1.3335237

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
  • DOI: 10.1063/1.1883665

Study of in-vessel nonaxisymmetric ELM suppression coil concepts for ITER
journal, January 2008


Measurement of the Resistive-Wall-Mode Stability in a Rotating Plasma Using Active MHD Spectroscopy
journal, September 2004


Control of neoclassical tearing modes in DIII–D
journal, May 2002

  • La Haye, R. J.; Günter, S.; Humphreys, D. A.
  • Physics of Plasmas, Vol. 9, Issue 5
  • DOI: 10.1063/1.1456066

Understanding edge-localized mode mitigation by resonant magnetic perturbations on MAST
journal, March 2013


Normal mode approach to modelling of feedback stabilization of the resistive wall mode
journal, May 2003


Analysis of stable resistive wall modes in a rotating plasma
journal, December 2003

  • Garofalo, A. M.; Jensen, T. H.; Strait, E. J.
  • Physics of Plasmas, Vol. 10, Issue 12
  • DOI: 10.1063/1.1625942

Observation of Plasma Toroidal-Momentum Dissipation by Neoclassical Toroidal Viscosity
journal, June 2006


Observation of Plasma Rotation Driven by Static Nonaxisymmetric Magnetic Fields in a Tokamak
journal, November 2008


High resolution main-ion charge exchange spectroscopy in the DIII-D H-mode pedestal
journal, September 2016

  • Grierson, B. A.; Burrell, K. H.; Chrystal, C.
  • Review of Scientific Instruments, Vol. 87, Issue 11
  • DOI: 10.1063/1.4960604

Observation of spectrum effect on the measurement of intrinsic error field on EAST
journal, May 2016


Suppression of Large Edge-Localized Modes in High-Confinement DIII-D Plasmas with a Stochastic Magnetic Boundary
journal, June 2004


Corrigendum: Error field correction in DIII-D Ohmic plasmas with either handedness
journal, June 2012


Predicting rotation for ITER via studies of intrinsic torque and momentum transport in DIII-D
journal, May 2017

  • Chrystal, C.; Grierson, B. A.; Staebler, G. M.
  • Physics of Plasmas, Vol. 24, Issue 5
  • DOI: 10.1063/1.4979194

Works referencing / citing this record:

3D field phase-space control in tokamak plasmas
journal, September 2018


Progress in disruption prevention for ITER
journal, June 2019