Abstract
Experiments with the limiting density of a plasma generated in the Globus-M spherical tokamak operating in the ohmic heating regime show that, when the plasma density reaches a certain value at the center of the plasma filament, snake-type strong magnetohydrodynamic instability exciting the m/n = 1/1 mode arises. A further rise in the density causes an internal disruption of the plasma. Numerical simulation of the instability dynamics is performed, and the results of simulation are compared with experimental and theoretical data. Experimental and theoretical data are in good agreement. It is shown that the instability is associated with an increased amount of impurities in the plasma and that the limit in density is of a “technological,” rather than of a fundamental, character. With the vacuum chamber cleaned more thoroughly, this limit disappears and the snake instability is not observed. Accordingly, a plasma filament density of 1 × 1020 m−3 was attained with a Greenwald number as high as 95%.
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References
A. Weller, et al., Phys. Rev. Lett. 59, 2303 (1987).
R. D. Gill, et al., Nucl. Fusion 32, 723 (1992).
Hu Liqun, et al., Plasma Phys. Controlled Fusion 45, 349 (2003).
R. J. Buttery, R. Akers, E. Arends, et al., Nucl. Fussion 44, 1027 (2004).
S. M. Kaye, M. G. Bell, R. E. Bell, et al., Technical Report No. PPPL-3454 (Princeton, 2000).
J. A. Wesson, Plasma Phys. Controlled Fusion 37, A337 (1995).
G. Turri, et al., in Proceedings of the 31st EPS Conference on Controlled Fusion and Plasma Physics, London, 2004, Europhysics Conference Abstracts, Vol. 28A, p. 4.192.
I. Lehane, et al., in Proceedings of the 30th EPS Conference on Controlled Fusion and Plasma Physics, St. Petersburg, 2003, Europhysics Conference Abstracts, Vol. 27A, p. 3.092.
V. K. Gusev, et al., Nucl. Fusion 49, 104021 (2009).
V. K. Gusev, S. Yu. Tolstyakov, V. I. Varfolomeev, et al., Vopr. At. Nauki Tekh., Ser: Termoyad. Sintez, No. 1, 39 (2007).
M. I. Patrov, S. E. Bender, V. K. Gusev, et al., Fiz. Plazmy 33, 81 (2007) [Plasma Phys. Rep. 33, 81 (2007)].
V. K. Gusev, S. E. Bender, A. V. Dech, et al., Zh. Tekh. Fiz. 76(8), 25 (2006) [Tech. Phys. 51, 987 (2006)].
N. V. Sakharov, et al., in Proceedings of the 29th EPS Conference on Controlled Fusion and Plasma Physics, Montreux, Switzerland, 2002, p. 5.078.
V. K. Gusev, F. V. Chernyshev, V. E. Golant, et al., Nucl. Fusion 46, 584 (2006).
I. Yu. Senichenkov, V. A. Rozhansky, A. V. Bogomolov, et al., in Proceedings of the 35th EPS Conference on Plasma Physics, Hersonissos, Crete, Grecce, 2008, p. 2.046.
Yu. V. Pertov, S. E. Bender, V. K. Gusev, et al., “Plasma MHD Stability at Limiting Density on Globus”, in Proceedings of the 33rd EPS Conference on Plasma Physics, Roma, 2006, p. 4–103.
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Original Russian Text © M.I. Patrov, Yu.V. Petrov, V.K. Gusev, G.S. Kurskiev, A.N. Novokhatskii, S.A. Sakharov, S.Yu. Tolstyakov, 2011, published in Zhurnal Tekhnicheskoĭ Fiziki, 2011, Vol. 81, No. 9, pp. 38–44.
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Patrov, M.I., Petrov, Y.V., Gusev, V.K. et al. Snake instability in the plasma of the Globus-M spherical tokamak. Tech. Phys. 56, 1259–1265 (2011). https://doi.org/10.1134/S1063784211090180
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DOI: https://doi.org/10.1134/S1063784211090180