Observations of toroidicity-induced Alfven eigenmodes in a reversed field pinch plasma
- Consorzio RFX, Associazione Euratom-ENEA sulla Fusione, Corso Stati Uniti 4, 35127 Padova (Italy) and Associazione Euratom-ENEA sulla fusione, Centro Riccerche Frascati, Cassella Postale 65, 00044 Frascati (Italy)
High frequency peaks in the spectra of magnetic field signals have been detected at the edge of Extrap-T2R [P. R. Brunsell, H. Bergsaaker, M. Cecconello, J. R. Drake, R. M. Gravestijn, A. Hedqvist, and J.-A. Malmberg, Plasma Phys. Controlled Fusion, 43, 1457 (2001)]. The measured fluctuation is found to be mainly polarized along the toroidal direction, with high toroidal periodicity n and Alfvenic scaling (f{proportional_to}B/{radical}(m{sub i}n{sub i})). Calculations for a reversed field pinch plasma predict the existence of an edge resonant, high frequency, high-n number toroidicity-induced Alfven eigenmode with the observed frequency scaling. In addition, gas puffing experiments show that edge density fluctuations are responsible for the rapid changes of mode frequency. Finally a coupling with the electron drift turbulence is proposed as drive mechanism for the eigenmode.
- OSTI ID:
- 20736509
- Journal Information:
- Physics of Plasmas, Vol. 12, Issue 4; Other Information: DOI: 10.1063/1.1861896; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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