Skip to main content Accessibility help

Effect of toroidal Alfvén eigenmodes on fast particle confinement in the spherical tokamak Globus-M


In experiments with neutral beam injection at the early stage of a Globus-M discharge, instabilities were observed that were excited by fast ions in the frequency range of 50–200 kHz, which were identified as toroidal Alfvén eigenmodes (TAE) (Petrov et al., Plasma Phys. Rep., vol. 37, 2011, pp. 1001–1005). In contradiction with the NSTX and MAST tokamaks, a regime of TAE generation was realized with strongly developed single modes. Magnetic measurements with fast Mirnov probes have shown that most of the modes have toroidal number $n=1$ . The influence of the modes on the fast particle confinement was recorded by means of a tangentially directed neutral particle analyser (NPA) and neutron detector. Hydrogen and deuterium were used as target plasma and injected beam for study of the isotopic effect. At deuterium injection into the deuterium plasma, TAE led to the neutron rate dropping by 25 %, whereas NPA fluxes of high energy dropped by 75 %. At hydrogen injection, the drop in the measured NPA fluxes did not exceed 25 %.


Corresponding author

Email address for correspondence:


Hide All
Berk, H. L., Breizman, B. N. & Ye, H. 1992 Finite orbit energetic particle linear response to toroidal Alfvén eigenmodes. Phys. Lett. A 162, 475.
Cheng, C. Z. & Chance, M. S. 1986 Low- $n$ shear Alfvén spectra in axisymmetric toroidal plasmas. Phys. Fluids 11, 3695.
Darrow, D. S., Fredrickson, E. D., Gorelenkov, N. N., Roquemore, A. L. & Shinohara, K. 2008 MHD induced neutral beam ion loss from NSTX plasmas. Nucl. Fusion 48, 084004.
Duong, H. H., Heidbrink, W. W., Strait, E. J., Petrie, T. W., Lee, R., Moyer, R. A. & Watkins, J. G. 1993 Loss of energetic beam ions during TAE instabilities. Nucl. Fusion 33, 749.
Fredrickson, E. D., Cheng, C. Z., Darrow, D., Fu, G., Gorelenkov, N. N., Kramer, G., Medley, S. S., Menard, J., Roquemore, L., Stutman, D. & White, R. B. 2003 Wave driven fast ion loss in the national spherical torus experiment. Phys. Plasmas 16, 28522862.
Fredrickson, E. D. et al. 2009 Modeling fast-ion transport during toroidal Alfvén eigenmode avalanches in National Spherical Torus Experiment. Phys. Plasmas 16, 122505.
Fredrickson, E. D. et al. 2013 Fast-ion energy loss during TAE avalanches in the National Spherical Torus Experiment. Nucl. Fusion 53, 013006.
García-munõz, M., Fahrbach, H.-U., Günter, S., Igochine, V., Mantsinen, M. J., Maraschek, M., Martin, P., Piovesan, P., Sassenberg, K. & Zohm, H. 2008 Fast-ion losses due to high-frequency MHD perturbations in the ASDEX upgrade tokamak. Phys. Rev. Lett. 100, 055005.
Gryaznevich, M. P. & Sharapov, S. E. 2000 Frequency sweeping Alfvén instabilities driven by super-Alfvénic beams in the spherical tokamak START. Nucl. Fusion 40, 907.
Gryaznevich, M. P. & Sharapov, S. E. 2004 Beta-dependence of energetic particle-driven instabilities in spherical tokamaks. Plasma Phys. Control. Fusion 46, S15.
Gryaznevich, M. P. & Sharapov, S. E. 2006 Perturbative and non-perturbative modes in START and MAST. Nucl. Fusion 46, S942.
Gusev, V. K. et al. 1999 Globus-M spherical tokamak. Tech. Phys. 44, 10541057.
Gusev, V. K. et al. 2007 Tech. Phys. 44, 11271143.
Gusev, V. K. et al. 2011 Investigation of beam– and wave–plasma interactions in spherical tokamak Globus-M. Nucl. Fusion 51, 103019.
Heidbrink, W. W., Strait, E. J., Doyle, E., Sager, G. & Snider, R. T. 1991 An investigation of beam driven Alfvén instabilities in the DIII-D tokamak. Nucl. Fusion 31, 1635.
Kornev, V. A., Askinazi, L. G., Vildjunas, M. I., Zhubr, N. A., Krikunov, S. V., Lebedev, S. V., Razumenko, D. V., Rozhdestvensky, V. V. & Tukachinsky, A. S. 2013 Confinement of energetic ions in a tokamak plasma at magnetic field in the range of 0.7–1.0 T. Tech. Phys. Lett. 39, 290293.
Kuteev, B. V., Goncharov, P. R., Sergeev, V. Yu. & khripunov, V. I. 2010 Intense fusion neutron sources. Plasma Phys. Rep. 36, 281317.
Kuteev, B. V. et al. 2011 Steady-state operation in compact tokamaks with copper coils. Nucl. Fusion 51, 073013.
Minaev, V. et al. 2014 Globus-M2 design peculiarities and status of the tokamak upgrade. In Proceedings of 25th FEC IAEA Conference, St. Petersburg, Russia, 13–18 October 2014. Conference ID: 46091 (CN-221), FIP/P8-25.
Peng, Y. K. et al. 2005 A component test facility based on the spherical tokamak. Plasma Phys. Control. Fusion 47, B263.
Petrov, Yu. V. 2014 The influence of toroidal Alfvén modes on the confinement of fast particles in the Globus-M spherical tokamak. Tech. Phys. Lett. 40 (12), 11361139.
Petrov, Yu. V., Patrov, M. I., Gusev, V. K., Ivanov, A. E., Minaev, V. B., Sakharov, N. V., Tolstyakov, S. Yu. & kurskiev, G. S. 2011 Experimental study of toroidal Alfvén modes in the Globus-M spherical tokamak. Plasma Phys. Rep. 37, 10011005.
Podesta, M. et al. 2009 Experimental studies on fast-ion transport by Alfvén wave avalanches on the National Spherical Torus Experiment. Phys. Plasmas 16, 056104.
Podesta, M., Bell, R. E., Bortolon, A., Crocker, N. A., Darrow, D. S. & Diallo, A. 2012 Study of chirping toroidicity-induced Alfvén eigenmodes in the National Spherical Torus Experiment. Nucl. Fusion 52, 094001.
Strait, E. J., Heidbrink, W. W., Turnbull, A. D., Chu, M. S. & Duong, H. H. 1993 Doppler shift of the TAE mode frequency in DIII-D. Nucl. Fusion 33, 18491870.
Strait, E. J., Heidbrink, W. W. & Turnbull, A. D. 1994 Doppler shift of the TAE mode frequency in DIII-D. Plasma Phys. Control. Fusion 36, 12111226.
Voss, G. M., Davis, S., Dnestrovskij, A., Kirk, A., Knight, P. J., Loughlin, M., O’brien, M. H., Sychugov, D., Tabasso, A. & Wilson, H. R. 2008 Conceptual design of a component test facility based on the spherical tokamak. Fusion Engng Des. 83, 16481653.
Wong, K. L. et al. 1991 Excitation of toroidal Alfvén eigenmodes in TFTR. Phys. Rev. Lett. 66, 1874.
MathJax is a JavaScript display engine for mathematics. For more information see


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed