Phenomenology of Compressional Alfven Eigenmodes

Technical Report · Thu May 13 04:00:00 EDT 2004

DOI:https://doi.org/10.2172/827942· OSTI ID:827942

Fredrickson, E D ^[1]; Gorelenkov, N N; Menard, J

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1. Princeton Plasma Physics Laboratory

Coherent oscillations with frequency 0.3 {le} {omega}/{omega}{sub ci} {le} 1, are seen in the National Spherical Torus Experiment [M. Ono, S.M. Kaye, Y-K.M. Peng, et al., Nucl. Fusion 40, 557 (2000)]. This paper presents new data and analysis comparing characteristics of the observed modes to the model of compressional Alfven eigenmodes (CAE). The toroidal mode number has been measured and is typically between 7 < n < 9. The polarization of the modes, measured using an array of four Mirnov coils, is found to be compressional. The frequency scaling of the modes agrees with the predictions of a numerical 2-D code, but the detailed structure of the spectrum is not captured with the simple model. The fast ion distribution function, as calculated with the beam deposition code in TRANSP [R.V. Budny, Nucl. Fusion 34, 1247 (1994)], is shown to be qualitatively consistent with the constraints of the Doppler-shifted cyclotron resonance drive model. This model also predicts the observed scaling of the low frequency limit for CAE.

• Research Organization: Princeton Plasma Physics Lab., Princeton, NJ (US)
• Sponsoring Organization: USDOE Office of Science (SC) (US)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 827942
• Report Number(s): PPPL-3955
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ALFVEN WAVES
CYCLOTRON RESONANCE
DEPOSITION
DISTRIBUTION FUNCTIONS
MHD INSTABILITY
OSCILLATIONS
POLARIZATION
SPHERICAL TOKAMAK