Controlled neoclassical tearing mode (NTM) healing by fueling pellets and its impact on electron cyclotron current drive requirements for complete NTM stabilization

Bardoczi, Laszlo; Choi, Minjun J.; Bañon-Navarro, Alejandro; Shiraki, Daisuke; La Haye, Robert John; Park, S. H.; Knölker, M.; Evans, Todd E.; McKee, George R.; Woo, Minho; Park, B. H.; Jenko, Frank

doi:10.1088/1741-4326/ab472d

Title: Controlled neoclassical tearing mode (NTM) healing by fueling pellets and its impact on electron cyclotron current drive requirements for complete NTM stabilization

Journal Article · Wed Oct 23 00:00:00 EDT 2019 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/ab472d· OSTI ID:1569040

^[1];

^[2]; Bañon-Navarro, Alejandro ^[3];

^[4]; La Haye, Robert John ^[5]; Park, S. H. ^[2];

^[6];

^[7];

^[8]; Woo, Minho ^[2]; Park, B. H. ^[2];

^[9]

Univ. of California, Los Angeles, CA (United States)
National Fusion Research Inst., Daejeon (Republic of Korea)
Max Planck Institute for Plasma Physics, Garching (Germany)
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
General Atomics, San Diego, CA (United States)
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Univ. of California - San Diego, San Diego, CA (United States)
Univ. of Wisconsin, Madison, WI (United States)
Max-Planck-Inst. of Plasma Physics, Bayern (Germany)

Controlled partial stabilization of core m/n – 2/1 Neoclassical Tearing Modes (NTMs) by fueling deuterium pellets is reported in DIII-D and KSTAR H-mode plasmas (m=n are the poloidal/toroidal mode numbers). Analyses of DIII-D data exploring possible physics origins show that an explanation is offered by NTM-turbulence multi-scale interaction, triggered by a sudden increase of local gradients near q–2 caused by the pellet. Pellet injection from the high-field side allows deep fueling which reaches the island region. In turn, low-k turbulent density fluctuations (ñ) increase by 30% in the island region. This ñ can drive transport across the island separatrices, reducing the pressure at spot at the O-point and diminishing the NTM drive. The Mirnov probe array detects the reduction of the 2/1 magnetic amplitude by up to 20%. Causality between elevated gradients outside of the island, turbulence spreading into the island and reduced NTM drive is qualitatively supported by non-linear gyrokinetic turbulence simulations. These demonstrate increased penetration of ion-scale ñ from the background plasma to the O-point region when the background gradient is increased. This interaction has potentially far reaching consequences as it can can lead to a reduction of the required electron cyclotron current density (j_ECCD) for NTM suppression by 70%, as predicted by the modified Rutherford equation. Furthermore, this beneicial effect of fueling pellets can be important as j_ECCD is the anticipated active NTM control technique for the International Thermonuclear Experimental Reactor (ITER), but its efficiency will be lowered by third harmonic absorption in Pre-Fusion Power Operation-1 (PFPO-1) at half magnetic field.

View Accepted Manuscript (DOE)

Cite

Export

Save

Research Organization:: General Atomics, San Diego, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Fusion Energy Sciences (FES); Ministry of Science, ICT and Future Planning (MSIT)

Grant/Contract Number:: FC02-04ER54698; AC05-00OR22725

OSTI ID:: 1569040

Alternate ID(s):: OSTI ID: 1657912

Journal Information:: Nuclear Fusion, Vol. 59, Issue 12; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

Citation Metrics:

Cited by: 5 works

Citation information provided by
Web of Science

References (49)

Spatiotemporal changes in the pressure-driven current densities on DIII-D due to magnetic islands Petty, C. C.; Jayakumar, R. J.; Makowski, M. A. Nuclear Fusion, Vol. 52, Issue 1 https://doi.org/10.1088/0029-5515/52/1/013011	journal	December 2011
Magnetic-Flux Pumping in High-Performance, Stationary Plasmas with Tearing Modes Petty, C. C.; Austin, M. E.; Holcomb, C. T. Physical Review Letters, Vol. 102, Issue 4 https://doi.org/10.1103/PhysRevLett.102.045005	journal	January 2009
Persistent density perturbations at rational- q surfaces following pellet injection in the Joint European Torus Weller, A.; Cheetham, A. D.; Edwards, A. W. Physical Review Letters, Vol. 59, Issue 20 https://doi.org/10.1103/PhysRevLett.59.2303	journal	November 1987
Electron cyclotron emission radiometer upgrade on the DIII-D tokamak Austin, M. E.; Lohr, J. Review of Scientific Instruments, Vol. 74, Issue 3 https://doi.org/10.1063/1.1530387	journal	March 2003
Origin of Tokamak Density Limit Scalings Gates, D. A.; Delgado-Aparicio, L. Physical Review Letters, Vol. 108, Issue 16 https://doi.org/10.1103/PhysRevLett.108.165004	journal	April 2012
Thomson scattering diagnostic upgrade on DIII-D Ponce-Marquez, D. M.; Bray, B. D.; Deterly, T. M. Review of Scientific Instruments, Vol. 81, Issue 10 https://doi.org/10.1063/1.3495759	journal	October 2010
Tomography of (2, 1) and (3, 2) magnetic island structures on Tokamak Fusion Test Reactor Nagayama, Y.; Taylor, G.; Fredrickson, E. D. Physics of Plasmas, Vol. 3, Issue 7 https://doi.org/10.1063/1.871534	journal	July 1996
Helical temperature perturbations associated with tearing modes in tokamak plasmas Fitzpatrick, Richard Physics of Plasmas, Vol. 2, Issue 3 https://doi.org/10.1063/1.871434	journal	March 1995
Multi-field/-scale interactions of turbulence with neoclassical tearing mode magnetic islands in the DIII-D tokamak Bardóczi, L.; Rhodes, T. L.; Bañón Navarro, A. Physics of Plasmas, Vol. 24, Issue 5 https://doi.org/10.1063/1.4977533	journal	May 2017
The nonlinear coupling between gyroradius scale turbulence and mesoscale magnetic islands in fusion plasmas Hornsby, W. A.; Peeters, A. G.; Snodin, A. P. Physics of Plasmas, Vol. 17, Issue 9 https://doi.org/10.1063/1.3467502	journal	September 2010
Beta limits in long-pulse tokamak discharges Sauter, O.; La Haye, R. J.; Chang, Z. Physics of Plasmas, Vol. 4, Issue 5 https://doi.org/10.1063/1.872270	journal	May 1997
Radial propagation of turbulence in tokamaks Garbet, X.; Laurent, L.; Samain, A. Nuclear Fusion, Vol. 34, Issue 7 https://doi.org/10.1088/0029-5515/34/7/I04	journal	July 1994
Improved core fueling with high field side pellet injection in the DIII-D tokamak Baylor, L. R.; Jernigan, T. C.; Combs, S. K. Physics of Plasmas, Vol. 7, Issue 5 https://doi.org/10.1063/1.874011	journal	May 2000
Hysteresis Relation between Turbulence and Temperature Modulation during the Heat Pulse Propagation into a Magnetic Island in DIII-D Ida, K.; Kobayashi, T.; Ono, M. Physical Review Letters, Vol. 120, Issue 24 https://doi.org/10.1103/PhysRevLett.120.245001	journal	June 2018
Improved charge-coupled device detectors for high-speed, charge exchange spectroscopy studies on the DIII-D tokamak Burrell, K. H.; Gohil, P.; Groebner, R. J. Review of Scientific Instruments, Vol. 75, Issue 10 https://doi.org/10.1063/1.1787949	journal	October 2004
Quantitative modeling of neoclassical tearing mode driven fast ion transport in integrated TRANSP simulations Bardóczi, L.; Podestà, M.; Heidbrink, W. W. Plasma Physics and Controlled Fusion, Vol. 61, Issue 5 https://doi.org/10.1088/1361-6587/ab0f08	journal	April 2019
Electron temperature gradient driven turbulence Jenko, F.; Dorland, W.; Kotschenreuther, M. Physics of Plasmas, Vol. 7, Issue 5 https://doi.org/10.1063/1.874014	journal	May 2000
Magnetic island structures and their rotation after pellet injection in FTU Giovannozzi, E.; Annibaldi, S. V.; Buratti, P. Nuclear Fusion, Vol. 44, Issue 2 https://doi.org/10.1088/0029-5515/44/2/002	journal	January 2004
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 Bardóczi, L.; Rhodes, T. L.; Carter, T. A. Physics of Plasmas, Vol. 24, Issue 6 https://doi.org/10.1063/1.4985078	journal	June 2017
Advanced control of neoclassical tearing modes in DIII-D with real-time steering of the electron cyclotron current drive Welander, A. S.; Kolemen, E.; La Haye, R. J. Plasma Physics and Controlled Fusion, Vol. 55, Issue 12 https://doi.org/10.1088/0741-3335/55/12/124033	journal	November 2013
Impact of neoclassical tearing mode–turbulence multi-scale interaction in global confinement degradation and magnetic island stability Bardóczi, L.; Carter, T. A.; La Haye, R. J. Physics of Plasmas, Vol. 24, Issue 12 https://doi.org/10.1063/1.5004987	journal	December 2017
Investigation of the role of pedestal pressure and collisionality on type-I ELM divertor heat loads in DIII-D Knolker, M.; Bortolon, A.; Canal, G. P. Nuclear Fusion, Vol. 58, Issue 9 https://doi.org/10.1088/1741-4326/aace92	journal	July 2018
Modulation of Core Turbulent Density Fluctuations by Large-Scale Neoclassical Tearing Mode Islands in the DIII-D Tokamak Bardóczi, L.; Rhodes, T. L.; Carter, T. A. Physical Review Letters, Vol. 116, Issue 21 https://doi.org/10.1103/PhysRevLett.116.215001	journal	May 2016
Edge localized modes and the pedestal: A model based on coupled peeling–ballooning modes Snyder, P. B.; Wilson, H. R.; Ferron, J. R. Physics of Plasmas, Vol. 9, Issue 5 https://doi.org/10.1063/1.1449463	journal	May 2002
Fiber optic two-color vibration compensated interferometer for plasma density measurements Van Zeeland, M. A.; Boivin, R. L.; Carlstrom, T. N. Review of Scientific Instruments, Vol. 77, Issue 10 https://doi.org/10.1063/1.2336437	journal	October 2006
Impact of rotating magnetic islands on density profile flattening and turbulent transport Zarzoso, D.; Hornsby, W. A.; Poli, E. Nuclear Fusion, Vol. 55, Issue 11 https://doi.org/10.1088/0029-5515/55/11/113018	journal	September 2015
Experimental particle transport studies by pellet injection in helical equilibria Terranova, D.; Auriemma, F.; Canton, A. Nuclear Fusion, Vol. 50, Issue 3 https://doi.org/10.1088/0029-5515/50/3/035006	journal	February 2010
A design retrospective of the DIII-D tokamak Luxon, J. L. Nuclear Fusion, Vol. 42, Issue 5 https://doi.org/10.1088/0029-5515/42/5/313	journal	May 2002
Enhanced central fuelling and m = 1 island formation after pellet ablation in the Frascati Tokamak Upgrade Annibaldi, S. V.; Buratti, P.; Giovannozzi, E. Nuclear Fusion, Vol. 44, Issue 1 https://doi.org/10.1088/0029-5515/44/1/002	journal	December 2003
The influence of rotation on the βN threshold for the 2∕1 neoclassical tearing mode in DIII-D Buttery, R. J.; La Haye, R. J.; Gohil, P. Physics of Plasmas, Vol. 15, Issue 5 https://doi.org/10.1063/1.2894215	journal	May 2008
Multiscale interaction between a large scale magnetic island and small scale turbulence Choi, M. J.; Kim, J.; Kwon, J. -M. Nuclear Fusion, Vol. 57, Issue 12 https://doi.org/10.1088/1741-4326/aa86fe	journal	October 2017
Non-perturbative measurement of cross-field thermal diffusivity reduction at the O-point of 2/1 neoclassical tearing mode islands in the DIII-D tokamak Bardóczi, L.; Rhodes, T. L.; Carter, T. A. Physics of Plasmas, Vol. 23, Issue 5 https://doi.org/10.1063/1.4948560	journal	May 2016
Polarimetry of motional Stark effect and determination of current profiles in DIII‐D (invited) Wróblewski, D.; Lao, L. L. Review of Scientific Instruments, Vol. 63, Issue 10 https://doi.org/10.1063/1.1143463	journal	October 1992
Complete suppression of the m = 2/ n = 1 neoclassical tearing mode using electron cyclotron current drive in DIII-D Petty, C. C.; Haye, R. J. La; Luce, T. C. Nuclear Fusion, Vol. 44, Issue 2 https://doi.org/10.1088/0029-5515/44/2/004	journal	January 2004
Active control of MHD instabilities by ECCD in ASDEX Upgrade Maraschek, M.; Gantenbein, G.; Goodman, T. P. Nuclear Fusion, Vol. 45, Issue 11 https://doi.org/10.1088/0029-5515/45/11/018	journal	October 2005
Suppression of Tearing Modes by Radio Frequency Current Condensation Reiman, A. H.; Fisch, N. J. Physical Review Letters, Vol. 121, Issue 22 https://doi.org/10.1103/PhysRevLett.121.225001	journal	November 2018
Observation of the “Self-Healing” of an Error Field Island in the Large Helical Device Narihara, K.; Watanabe, K. Y.; Yamada, I. Physical Review Letters, Vol. 87, Issue 13 https://doi.org/10.1103/PhysRevLett.87.135002	journal	September 2001
Turbulence spreading into the linearly stable zone and transport scaling Hahm, T. S.; Diamond, P. H.; Lin, Z. Plasma Physics and Controlled Fusion, Vol. 46, Issue 5A https://doi.org/10.1088/0741-3335/46/5A/036	journal	April 2004
Control of neoclassical tearing modes in DIII–D La Haye, R. J.; Günter, S.; Humphreys, D. A. Physics of Plasmas, Vol. 9, Issue 5 https://doi.org/10.1063/1.1456066	journal	May 2002
Electronics and Optoelectronics Based on Two-Dimensional Materials Vu, Quoc An; Yu, Woo Jong Journal of the Korean Physical Society, Vol. 73, Issue 1 https://doi.org/10.3938/jkps.73.1	journal	July 2018
The influence of finite radial transport on the structure and evolution of m / n = 2/1 neoclassical tearing modes on MAST Snape, J. A.; Gibson, K. J.; O'Gorman, T. Plasma Physics and Controlled Fusion, Vol. 54, Issue 8 https://doi.org/10.1088/0741-3335/54/8/085001	journal	May 2012
Comparisons and physics basis of tokamak transport models and turbulence simulations Dimits, A. M.; Bateman, G.; Beer, M. A. Physics of Plasmas, Vol. 7, Issue 3 https://doi.org/10.1063/1.873896	journal	March 2000
Stabilization of a magnetic island by localized heating in a tokamak with stiff temperature profile Maget, Patrick; Widmer, Fabien; Février, Olivier Physics of Plasmas, Vol. 25, Issue 2 https://doi.org/10.1063/1.5021759	journal	February 2018
Effect of magnetic islands on profiles, flows, turbulence and transport in nonlinear gyrokinetic simulations Navarro, A. Bañón; Bardóczi, L.; Carter, T. A. Plasma Physics and Controlled Fusion, Vol. 59, Issue 3 https://doi.org/10.1088/1361-6587/aa557e	journal	February 2017
Wide-field turbulence imaging with beam emission spectroscopy McKee, G. R.; Fonck, R. J.; Shafer, M. W. Review of Scientific Instruments, Vol. 81, Issue 10 https://doi.org/10.1063/1.3495788	journal	October 2010
Analysis of the structure of neoclassical tearing modes in ASDEX Upgrade Meskat, J. P.; Zohm, H.; Gantenbein, G. Plasma Physics and Controlled Fusion, Vol. 43, Issue 10 https://doi.org/10.1088/0741-3335/43/10/304	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 King, J. D.; La Haye, R. J.; Petty, C. C. Physics of Plasmas, Vol. 19, Issue 2 https://doi.org/10.1063/1.3684648	journal	February 2012
Island bootstrap current modification of the nonlinear dynamics of the tearing mode Carrera, R.; Hazeltine, R. D.; Kotschenreuther, M. Physics of Fluids, Vol. 29, Issue 4 https://doi.org/10.1063/1.865682	journal	January 1986
Multiscale interaction between a large scale magnetic island and small scale turbulence Choi, M. J.; Kim, J.; Kwon, J. -M. arXiv https://doi.org/10.48550/arxiv.1705.09487	text	January 2017