Observation of Reversed Shear Alfven Eigenmodes between Sawtooth Crashes in the Alcator C-Mod Tokamak

Journal Article · Fri Apr 24 00:00:00 EDT 2009 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.102.165003· OSTI ID:21316645

Edlund, E M; Porkolab, M; Lin, L; Lin, Y; Wukitch, S J ^[1]; Kramer, G J ^[2]

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1. MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States)
2. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

Groups of frequency chirping modes observed between sawtooth crashes in the Alcator C-Mod tokamak are interpreted as reversed shear Alfven eigenmodes near the q=1 surface. These modes indicate that a reversed shear q profile is generated during the relaxation phase of the sawtooth cycle. Two important parameters, q{sub min} and its radial position, are deduced from comparisons of measured density fluctuations with calculations from the ideal MHD code NOVA. These studies provide valuable constraints for further modeling of the sawtooth cycle.

• OSTI ID: 21316645
• Journal Information: Physical Review Letters, Vol. 102, Issue 16; Other Information: DOI: 10.1103/PhysRevLett.102.165003; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ALCATOR DEVICE
MAGNETOHYDRODYNAMICS
PLASMA INSTABILITY
REVERSED SHEAR
SAWTOOTH OSCILLATIONS