1 / 23

１ ) Drift mode observation in tokamak plasmas 2) Bicoherence analysis between zonal flow

Three wave coupling of drift wave modes in tokamak core plasmas Y. Hamada, T. Watari, A. Nishizawa, T. Ido, M. Kojima, K. Toi NIFS, Japan, April,’08 , at C.I.R.M. Marseille. １ ) Drift mode observation in tokamak plasmas 2) Bicoherence analysis between zonal flow

gunda
Download Presentation

１ ) Drift mode observation in tokamak plasmas 2) Bicoherence analysis between zonal flow

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Three wave coupling of drift wave modes in tokamak core plasmasY. Hamada, T. Watari, A. Nishizawa, T. Ido, M. Kojima, K. Toi NIFS, Japan, April,’08 , at C.I.R.M. Marseille １) Drift mode observation in tokamak plasmas 2) Bicoherence analysis between zonal flow and drift-wave turbulence 3) Cascading andinverse cascading in the drift-wave turbulence

  2. Ｓｅｔｕｐ　ｏｆ　Ｈｅａｖｙ　Ｉｏｎ　ＢｅａｍＳｅｔｕｐ　ｏｆ　Ｈｅａｖｙ　Ｉｏｎ　Ｂｅａｍ Ｐｒｏｂｅ　（ＨＩＢＰ）　ｉｎ　ＪＩＰＰ－ＴＩＩＵ Bt=3 T Rp=92 cm ap=23 cm

  3. Sample volumes and radial profiles Heated OH phase Te(0) ne(0)

  4. Typical Waveform of Potential and Density in the Core (A4) and Outer Area (C2), and Correlations . Outer Area Core Y. Hamada et. al., PRL, 96, 115003（06)

  5. 2-D Fourier Spectra of Φ at OH and Heating phases

  6. Setup of FIR scattering D.L.Brower, RSI (‘88) 1559

  7. Difference of turbulence spectrum in low and high-density OH plasmas D.L.Brower et al, RSI (‘88) 1559

  8. Uni-modal behavior of TFTR ITG plasmasa R.D.Durst et. al., PRL71(‘93)3135

  9. GAM’s radial coherence length At A4 (nearly parallet to manetic surface) At A2 (nearly perp. to magnetic surface) Y.Hamada et al., PPCF ４８(06) S177.

  10. Equations of bicoherence Bispectrum Biscoherence

  11. bispectrum, and sum of squared bicoherence The sum of squared bicoherence scrambled Frequency(kHz) Frequency (kHz) Bispectrum Squared bicoherence

  12. Bicoherence between zonal flow and drift-wave <ne(1)ne(-1)F(0)> ne(2)ne(-2)F(0)> <ne(3)ne(-3)F(0)> Squared bicoherence

  13. Bicoherence of heated plasma at r/ap =0.2

  14. Bicoherence in drift modes (cascading or inverse ｃascading) Sum of Squared bicoherence Frequency (kHz) Y. Hamada, to be submitted to PRL

  15. Bicoherence in inverse cascading Frequency(kHz) Frequency (kHz)

  16. Bicoherence in inverse cascading

  17. Bicoherence in drift modes (cascading or inverse cascading) Sum of squared bicoherence Frequency (kHz)

  18. Bicoherence in cascading

  19. Hasegawa－Mimaequation

  20. Mode coupling between l=1,2 and 3 TEM waves

  21. ConclusionI • The low density OH plasma where Te is much higher than Ti, the core is unimodal in TEM turbulence. Strong HF zonal flow in GAM frequency range and very small low frequency zonal flow are observed. • Clear mode coupling (bicoherence) between density and zonal flow potential was observed. The case of l1 + l2 + l3≠ 0, 6 the bicoherence goes down to noise level.

  22. ConclusionII • The bicoherence between drift wave modes, as was shown in this presentation, is large in spite of the limitation due to the large damping factor by finite sample volume effect and the Nyquist number limitation. At present I can not say sure whether it is cascading or inverse cascading coupling. If we are careful we think we can judge the obtained bicoherence is due to inverse cascading or due to cascading beyonds the Nyquist wavenumber limit.

  23. Thank YouFor Ｙour Attention

More Related