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The merits of ion cyclotron resonance heating schemes for sawtooth control in tokamak plasmas

Part of: Culham Thesis Prize Winners Focus on Fusion

Published online by Cambridge University Press:  21 September 2015

I. T. Chapman ,
J. P. Graves ,
M. Lennholm ,
J. Faustin ,
E. Lerche ,
T. Johnson ,
S. Tholerus  and
JET contributors
I. T. Chapman*
Affiliation:
EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB, UK CCFE, Culham Science Centre, Abingdon OX14 3DB, UK
J. P. Graves
Affiliation:
EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB, UK Ecole Polytechnique Federale de Lausanne, Centre de Recherches en Physique des Plasmas, 1015 Lausanne, Switzerland
M. Lennholm
Affiliation:
EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB, UK European Commission, JET Exploitation Unit, Culham Science Centre, Abingdon OX14 3DB, UK
J. Faustin
Affiliation:
EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB, UK Ecole Polytechnique Federale de Lausanne, Centre de Recherches en Physique des Plasmas, 1015 Lausanne, Switzerland
E. Lerche
Affiliation:
EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB, UK LPP-ERM/KMS, TEC Partner, Brussels, Belgium
T. Johnson
Affiliation:
EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB, UK VR, KTH, SE-100 44 Stockholm, Sweden
S. Tholerus
Affiliation:
EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB, UK VR, KTH, SE-100 44 Stockholm, Sweden
*
†Email address for correspondence: ian.chapman@ccfe.ac.uk
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Abstract

JET experiments have compared the efficacy of low- and high-field side ion cyclotron resonance heating (ICRH) as an actuator to deliberately minimise the sawtooth period. It is found that low-field side ICRH with low minority concentration is optimal for sawtooth control for two main reasons. Firstly, low-field side heating means that any toroidal phasing of the ICRH ( $-90^{\circ }$ , $+90^{\circ }$ or dipole) has a destabilising effect on the sawteeth, meaning that dipole phasing can be employed, since this is preferable due to less plasma wall interaction from Resonant Frequency (RF) sheaths. Secondly, the resonance position of the low-field side ICRH does not have to be very accurately placed to achieve sawtooth control, relaxing the requirement for real-time control of the RF frequency. These empirical observations have been confirmed by hybrid kinetic–magnetohydrodynamic modelling, and suggest that the ICRH antenna design for ITER is well positioned to provide a control actuator capable of having a significant effect on the sawtooth behaviour.

Type
Research Article
Information
Journal of Plasma Physics , Volume 81 , Issue 6 , December 2015 , 365810601
Copyright
© UK Atomic Energy Authority 2015 

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References

Angioni, C., Goodman, T., Henderson, M. & Sauter, O. 2003 Effects of localized electron heating and current drive on the sawtooth period. Nucl. Fusion 43, 455.Google Scholar
Angioni, C., Pochelon, A., Gorelenkov, N. N., McClements, K. G., Sauter, O., Budny, R. V., de Vries, P. C., Howell, D. F., Mantsinen, M., Nave, M. F. F., Sharapov, S. E.& contributors to the EFDA-JET Workprogramme 2002 Neutral beam stabilization of sawtooth oscillations in JET. Plasma Phys. Control. Fusion 44, 205.Google Scholar
Bhatnagar, V. P., Start, D. F. H, Jacquinot, J., Chaland, F., Cherubini, A. & Porcelli, F. 1994 Local magnetic shear control in a tokamak via fast wave minority ion current drive: theory and experiments in JET. Nucl. Fusion 34, 1579.Google Scholar
Briezman, B., Candy, J., Porcelli, F. & Berk, H. 1998 On the theory of internal kink oscillations. Phys. Plasmas 5, 2326.CrossRefGoogle Scholar
Budny, R. V., Bell, M. G., Biglari, H., Bitter, M., Bush, C. E., Cheng, C. Z., Fredrickson, E. D., Grek, B., Hill, K. W., Hsuan, H., Janos, A. C., Jassby, D. L., Johnson, D. W., Johnson, L. C., LeBlanc, B., McCune, D. C., Mikkelsen, D. R., Park, H. K., Ramsey, A. T., Sabbagh, S. A., Scott, S. D., Schivell, J. F., Strachan, J. D., Stratton, B. C., Synakowski, E. J., Taylor, G., Zarnstorff, M. C. & Zweben, S. J. 1992 Simulations of deuterium–tritium experiments in TFTR. Nucl. Fusion 32, 429.Google Scholar
Bussac, M. N., Pellat, R., Edery, D. & Soule, J. L. 1975 Internal kink modes in toroidal plasmas with circular cross sections. Phys. Rev. Lett. 35, 1638.Google Scholar
Chapman, I. T., Sharapov, S. E., Huysmans, G. T. A. & Mikhailovskii, A. B. 2006 Modeling the effect of toroidal plasma rotation on drift-magnetohydrodynamic modes in tokamaks. Phys. Plasmas 13, 062511.Google Scholar
Chapman, I. T., Buttery, R. J., Coda, S., Gerhardt, S., Graves, J. P., Howell, D. F., Isayama, A., La Haye, R. J., Liu, Y., Maget, P., Maraschek, M., Sabbagh, S., Sauter, O.& the ASDEX Upgrade, DIII-D, HL-2A, JT-60U, MAST, NSTX, TCV and Tore Supra Teams and JET-EFDA Contributors 2010a Empirical scaling of sawtooth period for onset of neoclassical tearing modes. Nucl. Fusion 50, 102001.Google Scholar
Chapman, I. T., Scannell, R., Cooper, W. A., Graves, J. P., Hastie, R. J., Naylor, G. & Zocco, A. 2010b Magnetic reconnection triggering magnetohydrodynamic instabilities during a sawtooth crash in a tokamak plasma. Phys. Rev. Lett. 105, 255002.Google Scholar
Chapman, I. T. 2011a Controlling sawtooth oscillations in tokamak plasmas. Plasma Phys. Control. Fusion 53, 013001.Google Scholar
Chapman, I. T., Graves, J. P., Johnson, T., Asunta, O., Bonoli, P., Choi, M., Jaeger, E. F., Jucker, M. & Sauter, O. 2011b Sawtooth control in ITER using ion cyclotron resonance heating. Plasma Phys. Control. Fusion 53, 124003.CrossRefGoogle Scholar
Chapman, I. T., La Haye, R. J., Buttery, R. J., Heidbrink, W. W., Jackson, G. L., Muscatello, C. M., Petty, C. C., Pinsker, R. I., Tobias, B. J. & Turco, F. 2012 Sawtooth control using electron cyclotron current drive in ITER demonstration plasmas in DIII-D. Nucl. Fusion 52, 063006.Google Scholar
Chapman, I. T., Graves, J. P., Sauter, O., Zucca, C., Asunta, O., Buttery, R. J., Coda, S., Goodman, T., Igochine, V., Johnson, T., Jucker, M., La Haye, R. J., Lennholm, M.& JET-EFDA Contributors 2013a Power requirements for electron cyclotron current drive and ion cyclotron resonance heating for sawtooth control in ITER. Nucl. Fusion 53, 066001.Google Scholar
Chapman, I. T., Igochine, V., Maraschek, M., McCarthy, P. J., Tardini, G.& the ASDEX Upgrade ECRH Group and the ASDEX Upgrade Team 2013b Sawtooth control using electron cyclotron current drive in the presence of energetic particles in high performance ASDEX Upgrade plasmas. Plasma Phys. Control. Fusion 55, 065009.CrossRefGoogle Scholar
Czarnecka, A., Zastrow, K.-D., Rzadkiewicz, J., Coffey, I. H., Lawson, K. D., O’Mullane, M. G.& JET-EFDA Contributors 2011 Determination of metal impurity density, ${\rm\Delta}Z_{\text{eff}}$ and dilution on JET by VUV emission spectroscopy. Plasma Phys. Control. Fusion 53, 035009.Google Scholar
Eriksson, L.-G., Johnson, T., Mayoral, M.-L., Coda, S., Sauter, O., Buttery, R. J., McDonald, D., Hellsten, T., Mantsinen, M. J., Mueck, A., Noterdaeme, J.-M., Santala, M., Westerhof, E., de Vries, P.& JET-EFDA contributors 2006 On ion cyclotron current drive for sawtooth control. Nucl. Fusion 46, S951.CrossRefGoogle Scholar
Fisch, N. J. 1987 Theory of current drive in plasmas. Rev. Mod. Phys. 59, 175.Google Scholar
Goodman, T. P., Felici, F., Sauter, O. & Graves, J. P. 2011 Sawtooth pacing by real-time auxiliary power control in a tokamak plasma. Phys. Rev. Lett. 106, 245002.Google Scholar
Graves, J. P. 2004 Influence of asymmetric energetic ion distributions on sawtooth stabilization. Phys. Rev. Lett. 92, 185003.Google Scholar
Graves, J. P. 2005 Sawtooth control in fusion plasmas. Phys. Plasmas 12, 090908.Google Scholar
Graves, J. P. 2009 Sawtooth-control mechanism using toroidally propagating ion-cyclotron-resonance waves in tokamaks. Phys. Rev. Lett. 102, 065005.Google Scholar
Graves, J. P., Chapman, I. T., Coda, S., Johnson, T., Lennholm, M., Alper, B., de Baar, M., Crombe, K., Eriksson, L.-G., Felton, R., Howell, D., Kiptily, V., Koslowski, H. R., Mayoral, M.-L., Monakhov, I., Nunes, I., Pinches, S. D.& JET-EFDA Contributors 2010 Experimental verification of sawtooth control by energetic particles in ion cyclotron resonance heated jet tokamak plasmas. Nucl. Fusion 50, 052002.Google Scholar
Graves, J. P., Chapman, I. T., Coda, S., Johnson, T., Lennholm, M., Paley, J. I., Sauter, O.& JET-EFDA Contributors 2011 Advances in sawtooth control. Fusion Sci. Technol. 59, 539.CrossRefGoogle Scholar
Graves, J. P., Chapman, I. T., Coda, S., Lennholm, M., Albergante, M. & Jucker, M. 2012 Control of magnetohydrodynamic stability by phase space engineering of energetic ions in tokamak plasmas. Nat. Commun. 3, 624.Google Scholar
Graves, J. P., Lennholm, M., Chapman, I. T., Lerche, E., Reich, M., Alper, B., Bobkov, V., Dumont, R., Faustin, J. M., Jacquet, P., Jaulmes, F., Johnson, T., Keeling, D. L., Liu, Yueqiang, Nicolas, T., Tholerus, S., Blackman, T., Carvalho, I. S., Coelho, R., Van Eester, D., Felton, R., Goniche, M., Kiptily, V., Monakhov, I., Nave, M. F. F., Perez von Thun, C., Sabot, R., Sozzi, C. & Tsalas, M. 2015 Sawtooth control in jet with ITER relevant low field side resonance ion cyclotron resonance heating and ITER-like wall. Plasma Phys. Control. Fusion 57, 014033.CrossRefGoogle Scholar
Hastie, R. J. & Hender, T. C. 1988 Toroidal internal kink stability in tokamaks with ultra flat $q$ profiles. Nucl. Fusion 28, 585.Google Scholar
Hedin, J., Hellsten, T., Eriksson, L.-G. & Johnson, T. 2002 The influence of finite drift orbit width on ICRF heating in toroidal plasmas. Nucl. Fusion 42, 527.Google Scholar
Hu, B., Betti, R. & Manickam, J. 2006 Kinetic stability of the internal kink mode in ITER. Phys. Plasmas 13, 112505.CrossRefGoogle Scholar
Huysmans, G. T. A. 1991 Proceedings of the CP90 Conference on Computational Physics, p. 371. World Scientific Publishing Co..Google Scholar
Igochine, V. G., Chapman, I. T., Bobkov, V., Günter, S., Maraschek, M., Moseev, D., Pereversev, G., Reich, M., Stober, J.& ASDEX Upgrade team 2011 Destabilization of fast particle stabilized sawteeth in ASDEX Upgrade with electron cyclotron current drive. Plasma Phys. Control. Fusion 53, 022002.Google Scholar
Jucker, M., Graves, J. P., Cooper, W. A. & Johnson, T. 2011 Ion cyclotron resonance heating with consistent finite orbit widths and anisotropic equilibria. Plasma Phys. Control. Fusion 53, 054010.Google Scholar
Kadomtsev, B. B. 1976 Disruptive instability in tokamaks. Sov. J. Plasma Phys. 1, 389.Google Scholar
Kim, D. & Sauter, O. 2014 Real-time sawtooth control and neoclassical tearing mode preemption in ITER. Phys. Plasmas 21, 061503.Google Scholar
Kruskal, M. & Oberman, C. 1958 On the stability of plasma in static equilibrium. Phys. Fluids 1, 275.Google Scholar
Lamalle, P., Beaumont, B., Kazarian, F., Gassmann, T., Agarici, G., Ajesh, P., Alonzo, T., Arambhadiya, B., Argouarch, A., Bamber, R., Berger-By, G., Bernard, J.-M., Brun, C., Carpentier, S., Clairet, F., Colas, L., Courtois, X., Davis, A., Dechelle, C., Doceul, L. & Dumortier, P. 2013 Status of the ITER ion cyclotron H and CD system. Fusion Engng Des. 88, 517.Google Scholar
Laxåback, M. & Hellsten, T. 2005 Modelling of minority ion cyclotron current drive during the activated phase of ITER. Nucl. Fusion 45, 1510.Google Scholar
Lennholm, M., Blackman, T., Chapman, I. T., Eriksson, L.-G., Graves, J. P., Howell, D. F., de Baar, M., Calabro, G., Dumont, R., Graham, M., Jachmich, S., Mayoral, M. L., Sozzi, C., Stamp, M., Tsalas, M., de Vries, P.& JET EFDA Contributors 2011 Feedback control of the sawtooth period through real time control of the ion cyclotron resonance frequency. Nucl. Fusion 51, 073032.Google Scholar
Lennholm, M., Frigione, D., Graves, J., Beaumont, P. S., Blackman, T., Carvalho, I. S., Chapman, I., Dumont, R., Felton, R., Garzotti, L., Goniche, M., Goodyear, A., Grist, D., Jachmich, S., Johnson, T., Lang, P., Lerche, E., de la Luna, E., Monakhov, I., Mooney, R., Morris, J., Nave, M. F. F., Reich, M., Rimini, F., Sips, G., Sheikh, H., Sozzi, C., Tsalas, M.& JET contributors 2015 Real-time control of ELM and sawtooth frequencies: similarities and differences. Nucl. Fusion (submitted).Google Scholar
Levinton, F. M., Batha, S. H., Yamada, M. & Zarnstorff, M. C. 1993 q-profile measurements in the tokamak fusion test reactor. Phys. Fluids B 5, 2554.CrossRefGoogle Scholar
Nunes, I., Balboa, I., Baruzzo, M., Challis, C., Drewelow, P., Frassinetti, L., Frigione, D., Garcia, J., Hobirk, J., Joffrin, E., Lomas, P. J., Lowry, C., Rimini, F., Sips, A. C. C., Wiesen, S.& JET EFDA contributors 2015 Compatibility of high performance operation with JET ILW. Nucl. Fusion (submitted).Google Scholar
Park, H. K., Luhmann, N. C. Jr., Donné, A. J. H., Classen, I. G. J., Domier, C. W., Mazzucato, E., Munsat, T., van de Pol, M. J. & Xia, Z. 2006 Observation of high-field-side crash and heat transfer during sawtooth oscillation in magnetically confined plasmas. Phys. Rev. Lett. 96, 195003.Google Scholar
Pinches, S. D., Appel, L. C., Candy, J., Sharapov, S. E., Berk, H. L., Borba, D., Breizman, B. N., Hender, T. C., Hopcraft, K. I., Huysmans, G. T. A. & Kerner, W. 1998 The HAGIS self-consistent nonlinear wave–particle interaction model. Comput. Phys. Commun. 111, 133.CrossRefGoogle Scholar
Porcelli, F. 1991 Fast particle stabilisation. Plasma Phys. Control. Fusion 33, 1601.Google Scholar
Porcelli, F., Boucher, D. & Rosenbluth, M. 1996 Model for the sawtooth period and amplitude. Plasma Phys. Control. Fusion 38, 2163.Google Scholar
Porcelli, F., Stankiewicz, R., Kerner, W. & Berk, H. 1994 Solution of the drift-kinetic equation for global plasma modes and finite particle orbit widths. Phys. Plasmas 1, 470.Google Scholar
Romanelli, F. 2015 Overview of the JET results. Nucl. Fusion 55, 104001.CrossRefGoogle Scholar
Sauter, O., Westerhof, E., Mayoral, M. L., Alper, B., Belo, P. A., Buttery, R. J., Gondhalekar, A., Hellsten, T., Hender, T. C., Howell, D. F., Johnson, T., Lamalle, P., Mantsinen, M. J., Milani, F., Nave, M. F. F., Nguyen, F., Pecquet, A. L., Pinches, S. D., Podda, S. & Rapp, J. 2002 Control of neoclassical tearing modes by sawtooth control. Phys. Rev. Lett. 88, 105001.Google Scholar
Shimada, M. 2007 ITER physics basis. Nucl. Fusion 47, S1.Google Scholar
Zohm, H. 2015 Recent ASDEX Upgrade research in support of ITER and DEMO. Nucl. Fusion 55, 104010.Google Scholar
Zucca, C.2008 In Joint Varenna–Lausanne Theory Conference, vol. 1069, p. 361. AIP.Google Scholar