Investigation of geodesic acoustic mode oscillations in the T-10 tokamak
| Autor: | S.V. Perfilov, S.A. Grashin, V.A. Vershkov, M.V. Ufimtsev, L. G. Zimeleva, A.V. Melnikov, L.G. Eliseev, A. O. Urazbaev, G. Van Oost, S. E. Lysenko, L. I. Krupnik, V.A. Mavrin, Sergey Soldatov, A. V. Gudozhnik, D. A. Shelukhin |
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| Rok vydání: | 2006 |
| Předmět: | |
| Zdroj: | Plasma Physics and Controlled Fusion. 48:S87-S110 |
| ISSN: | 1361-6587 0741-3335 |
| Popis: | Geodesic acoustic modes (GAMs) were investigated on the T-10 tokamak using heavy ion beam probe, correlation reflectometry and multipin Langmuir probe diagnostics. Regimes with Ohmic heating and with on- and off-axis ECRH were studied. It was shown that GAMs are mainly the potential oscillations. Typically, the power spectrum of the oscillations has the form of a solitary quasi-monochromatic peak with the contrast range 3–5. They are the manifestation of the torsional plasma oscillations with poloidal wavenumber m = 0, called zonal flows. The frequency of GAMs changes in the region of observation and decreases towards the plasma edge. After ECRH switch-on, the frequency increases, correlating with growth in the electron temperature Te. The frequency of the GAMs depends on the local Te as , which is consistent with a theoretical scaling for GAM, where cs is the sound speed within a factor of unity. The GAMs on T-10 are found to have density limit, some magnetic components and an intermittent character. They tend to be more excited near low-q magnetic surfaces. |
| Databáze: | OpenAIRE |
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