High-frequency core localized modes in neutral beam heated plasmas on TFTR

R. Nazikian; Z. Chang; E. D. Fredrickson; E. Mazzucato; S. H. Batha; R. Bell; R. Budny; C. E. Bush; C. Z. Cheng; A. Janos; F. Levinton; J. Manickam; D. K. Mansfield; H. K. Park; G. Rewoldt; S. Sabbagh; E. J. Synakowski; W. Tang; G. Taylor; L. E. Zakharov

doi:10.1063/1.871887

High-frequency core localized modes in neutral beam heated plasmas on TFTR

R. Nazikian, Z. Chang, E. D. Fredrickson, E. Mazzucato, S. H. Batha, R. Bell, R. Budny, C. E. Bush, C. Z. Cheng, A. Janos, F. Levinton, J. Manickam, D. K. Mansfield, H. K. Park, G. Rewoldt, S. Sabbagh, E. J. Synakowski, W. Tang, G. Taylor, L. E. Zakharov

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Abstract

A band of high-frequency modes in the range 50-150 kHz with intermediate toroidal mode numbers 4<n<10 are commonly observed in the core of supershot plasmas on TFTR [R- Hawryluk, Plasma Phys. Controlled Fusion 33, 1509 (1991)] Two distinct varieties of magnetohydrodynamic (MHD) modes are identified, corresponding to a flute-like mode predominantly appearing around the q = 1 surface and an outward ballooning mode for q>1. The flute-like modes have nearly equal amplitude on the high-field and low-held side of the magnetic axis, and are mostly observed in moderate performance supershot plasmas with τ_E<2τ_L, while the ballooning-like modes have enhanced amplitude on the low-field side of the magnetic axis and lend to appear in higher performance superhot plasmas with τ_E>2τ_L, where τ_L is the equivalent L-mode confinement time. Both modes appear to propagate in the ion diamanagnetic drift direction and are highly localized with radial widths Δr∼5-10 cm, fluctuation levels n̈/n, T̃_e/T_e<0.01. and radial displacements ξ_r.∼0.1 cm. Unlike the toroidally localized high-n activity observed just prior to major and minor disruptions on TFTR [E. D. Fredrickson et al., Proceedings of the 15th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Seville, Spain (International Atomic Energy Agency, Vienna, 1995), No. IAEA-CN-60/A-2-II-5], these modes are typically more benign and may be indicative of MHD activity excited by resonant circulating beam ions.

Original language	English
Pages (from-to)	593-605
Number of pages	13
Journal	Physics of Plasmas
Volume	3
Issue number	2
DOIs	https://doi.org/10.1063/1.871887
State	Published - Feb 1996

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Nazikian, R., Chang, Z., Fredrickson, E. D., Mazzucato, E., Batha, S. H., Bell, R., Budny, R., Bush, C. E., Cheng, C. Z., Janos, A., Levinton, F., Manickam, J., Mansfield, D. K., Park, H. K., Rewoldt, G., Sabbagh, S., Synakowski, E. J., Tang, W., Taylor, G., & Zakharov, L. E. (1996). High-frequency core localized modes in neutral beam heated plasmas on TFTR. Physics of Plasmas, 3(2), 593-605. https://doi.org/10.1063/1.871887

@article{adfe13bc6e7145da9b56c8fcef544e92,

title = "High-frequency core localized modes in neutral beam heated plasmas on TFTR",

abstract = "A band of high-frequency modes in the range 50-150 kHz with intermediate toroidal mode numbers 41. The flute-like modes have nearly equal amplitude on the high-field and low-held side of the magnetic axis, and are mostly observed in moderate performance supershot plasmas with τE<2τL, while the ballooning-like modes have enhanced amplitude on the low-field side of the magnetic axis and lend to appear in higher performance superhot plasmas with τE>2τL, where τL is the equivalent L-mode confinement time. Both modes appear to propagate in the ion diamanagnetic drift direction and are highly localized with radial widths Δr∼5-10 cm, fluctuation levels {\"n}/n, {\~T}e/Te<0.01. and radial displacements ξr.∼0.1 cm. Unlike the toroidally localized high-n activity observed just prior to major and minor disruptions on TFTR [E. D. Fredrickson et al., Proceedings of the 15th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Seville, Spain (International Atomic Energy Agency, Vienna, 1995), No. IAEA-CN-60/A-2-II-5], these modes are typically more benign and may be indicative of MHD activity excited by resonant circulating beam ions.",

author = "R. Nazikian and Z. Chang and Fredrickson, {E. D.} and E. Mazzucato and Batha, {S. H.} and R. Bell and R. Budny and Bush, {C. E.} and Cheng, {C. Z.} and A. Janos and F. Levinton and J. Manickam and Mansfield, {D. K.} and Park, {H. K.} and G. Rewoldt and S. Sabbagh and Synakowski, {E. J.} and W. Tang and G. Taylor and Zakharov, {L. E.}",

year = "1996",

month = feb,

doi = "10.1063/1.871887",

language = "English",

volume = "3",

pages = "593--605",

number = "2",

}

Nazikian, R, Chang, Z, Fredrickson, ED, Mazzucato, E, Batha, SH, Bell, R, Budny, R, Bush, CE, Cheng, CZ, Janos, A, Levinton, F, Manickam, J, Mansfield, DK, Park, HK, Rewoldt, G, Sabbagh, S, Synakowski, EJ, Tang, W, Taylor, G & Zakharov, LE 1996, 'High-frequency core localized modes in neutral beam heated plasmas on TFTR', Physics of Plasmas, vol. 3, no. 2, pp. 593-605. https://doi.org/10.1063/1.871887

TY - JOUR

T1 - High-frequency core localized modes in neutral beam heated plasmas on TFTR

AU - Nazikian, R.

AU - Chang, Z.

AU - Fredrickson, E. D.

AU - Mazzucato, E.

AU - Batha, S. H.

AU - Bell, R.

AU - Budny, R.

AU - Bush, C. E.

AU - Cheng, C. Z.

AU - Janos, A.

AU - Levinton, F.

AU - Manickam, J.

AU - Mansfield, D. K.

AU - Park, H. K.

AU - Rewoldt, G.

AU - Sabbagh, S.

AU - Synakowski, E. J.

AU - Tang, W.

AU - Taylor, G.

AU - Zakharov, L. E.

PY - 1996/2

Y1 - 1996/2

N2 - A band of high-frequency modes in the range 50-150 kHz with intermediate toroidal mode numbers 41. The flute-like modes have nearly equal amplitude on the high-field and low-held side of the magnetic axis, and are mostly observed in moderate performance supershot plasmas with τE<2τL, while the ballooning-like modes have enhanced amplitude on the low-field side of the magnetic axis and lend to appear in higher performance superhot plasmas with τE>2τL, where τL is the equivalent L-mode confinement time. Both modes appear to propagate in the ion diamanagnetic drift direction and are highly localized with radial widths Δr∼5-10 cm, fluctuation levels n̈/n, T̃e/Te<0.01. and radial displacements ξr.∼0.1 cm. Unlike the toroidally localized high-n activity observed just prior to major and minor disruptions on TFTR [E. D. Fredrickson et al., Proceedings of the 15th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Seville, Spain (International Atomic Energy Agency, Vienna, 1995), No. IAEA-CN-60/A-2-II-5], these modes are typically more benign and may be indicative of MHD activity excited by resonant circulating beam ions.

AB - A band of high-frequency modes in the range 50-150 kHz with intermediate toroidal mode numbers 41. The flute-like modes have nearly equal amplitude on the high-field and low-held side of the magnetic axis, and are mostly observed in moderate performance supershot plasmas with τE<2τL, while the ballooning-like modes have enhanced amplitude on the low-field side of the magnetic axis and lend to appear in higher performance superhot plasmas with τE>2τL, where τL is the equivalent L-mode confinement time. Both modes appear to propagate in the ion diamanagnetic drift direction and are highly localized with radial widths Δr∼5-10 cm, fluctuation levels n̈/n, T̃e/Te<0.01. and radial displacements ξr.∼0.1 cm. Unlike the toroidally localized high-n activity observed just prior to major and minor disruptions on TFTR [E. D. Fredrickson et al., Proceedings of the 15th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Seville, Spain (International Atomic Energy Agency, Vienna, 1995), No. IAEA-CN-60/A-2-II-5], these modes are typically more benign and may be indicative of MHD activity excited by resonant circulating beam ions.

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U2 - 10.1063/1.871887

DO - 10.1063/1.871887

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AN - SCOPUS:0040070457

SN - 1070-664X

VL - 3

SP - 593

EP - 605

JO - Physics of Plasmas

JF - Physics of Plasmas

IS - 2

ER -

High-frequency core localized modes in neutral beam heated plasmas on TFTR

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