Study of interactions between GAMs and broadband turbulence in the T-10 tokamak
| Autor: | V. N. Zenin, S. E. Lysenko, M.V. Ufimtsev, L.G. Eliseev, A.V. Melnikov |
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| Rok vydání: | 2017 |
| Předmět: |
Physics
Nuclear and High Energy Physics Electron density Tokamak Turbulence Plasma Reynolds stress Condensed Matter Physics 01 natural sciences 010305 fluids & plasmas Computational physics Magnetic field law.invention Nuclear physics Amplitude Physics::Plasma Physics law 0103 physical sciences 010306 general physics Dimensionless quantity |
| Zdroj: | Nuclear Fusion. 57:115001 |
| ISSN: | 1741-4326 0029-5515 |
| DOI: | 10.1088/1741-4326/aa796c |
| Popis: | New findings in study of geodesic acoustic modes (GAMs) on the T-10 tokamak since the last IAEA FEC 2014 are described. The broadband fluctuations of potential and electron density n e in Ohmic and ECRH regimes are analyzed with Heavy Ion Beam Probing along with fluctuations of poloidal magnetic field B pol. At the edge, at ρ > 0.8, the dominated GAM peak with frequency 17 kHz in potential fluctuations, and noticeable peak of quasi-coherent density and potential fluctuations with frequency 40–100 kHz and HFHM ~30 kHz are observed. During ECRH of high density ~ 4 × 1019 m−3 plasmas, the level of broadband fluctuations decreases, but the energy confinement degrades and the GAM amplitude on rises. The bi-spectral analysis of and n e fluctuations demonstrates the existence of statistically significant auto- and cross-bicoherence at the GAM frequency that points out to three-wave interaction between GAM and broadband electrostatic turbulence, while the cross-bicoherence for , n e and B pol indicates three-wave interaction between GAM and broadband electromagnetic turbulence. These three-wave interactions may be explained by quadratic character of nonlinear GAM generation, e.g. owing to Reynolds stress. |
| Databáze: | OpenAIRE |
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