Multi-scale turbulence experiment in HT-7 takamak Li Yadong Li Jiangang Zhang Xiaodong Ren Zhong Zhang Tou Lin Shiyao and HT-7 Team Institute of plasma physics.Chinese academy of sciences IFTS work shop (Hangzhon september 25~ )

DIII-D new results in 21 th IAEA Tore supra results in 21 th IAEA

The reverse result published by DIII-D and Tore Supra groups The key is looking for new fluctuation component in ETG mode range and find its correlation with electron heat transport

High-k fluctuation measurement k  =ak  + bk r DIII-D : micro-waves scattering system(k  =0~1;8~15;35~40 cm -1 ) (3 channels) Tore Supra : Doppler reflectometry (k  =3~20cm -1 ) AUG : Doppler reflectometry (k  =3~20cm -1 ) k r NSTX : micro-waves scattering system (k r =4~24cm -1 ) (5 channels) k  HT-7 : co 2 laser scattering system (k  =12~34cm -1 ) (3 channels) plan: five & six channel (k  =6~12cm -1,1~2 channels,heterodyne detection; k  =14~34cm -1,4 channels, homodyne detection) Tore Supra : ( plan) co 2 laser scattering system (k  =6~25cm -1,1 channel )

Turbulence wave-number spectra observed in Tore Supra by Doppler Reflectometry P.Hennequin 12 th EU-US TTF Marseille September 2006 Overview of recent electron heat transport F. Imbeaux 12 th EU-US TTF Marseille September 2006

CO 2 Laser collective scattering system in HT-7

Normalize S(k  ) spectra experiment in HT-7 NSTX Hennequin et al. PPCF 46, 2004 Tore Supra HT-7

Special normalize S(k  ) spectra HT-7

compare HT-7

Plasma microturbulence: Multiple scales Question for theory: What is the role of sub-ion scales? trapped electron modes ETG modes ITG modes Not shown here: - drift waves - ballooning modes T. Görler, 5 th July /20

model transform during n e ramp down experiment HT-7

The narrowband fluctuation component in HT-7 (ρ S ~1.3±0.2mm) V ph ~  10 5 cm/s V ph ~  10 5 cm/s HT-7

ΔP LHCD138  138kw The violent instability erupted in low hybrid current drive experiment HT-7

Δn e  0.8  m -3

The violent instability erupted was watched in medium and high k density fluctuation (k  =14cm-1 k  =23cm-1 ) in low hybrid wave drive experiment. We found there is a critical value that correlation with LHCD power and plasma density in HT-7. We didn’t find strong correlation with energetic particle. HT-7 Overview of recent electron heat transport F. Imbeaux 12 th EU-US TTF Marseille September 2006

Up and down anti-symmetry in density fluctuation measurement HT-7 K 1 =14cm -1 K 3 =23cm -1 K 2 =20cm -1

Systemic study anti-symmetry Next work K1K1 HT-7 K2K2 K3K3 adjust k i =5927.5cm -1 k ksks k=k s -k i =8~35cm -1  = o ~0.338 o ↔8~35cm -1 kiki

Plasma current ramp up and ramp down experiment HT-7

Plasma density ramp up and ramp down experiment HT-7

In plasma density slow ramp up and ramp down experiment we find little change in density fluctuation measurement. But in plasma current slow ramp up and ramp down experiment we find a change in density fluctuation measurement. That is T e profile change ?

Particle confinement and density fluctuation high frequency part HT-7

Narrowband fluctuation changed with the wavenumber spectrum HT-7

Next work for GEA mode experiment In HT-7 tokamak Change the area that main laser beam cross with local oscillator beams

The way of study fluctuations in tokamak Transport: Ion thermal Electron thermal Electron particle momentum n(r) T e (r) T i (r) J(r) q(r) E(r) …. external perturbation heating …. Fluctuation Spatial scale Many types of fluctuation with a different Spatial scale exist plasmas.the ion and Electron channel could be regulated by Different types of fluctuation with Interactions of such fluctuation Poloidal flow shear Negative magnetic shear Effect of normalized pressure gradient ……. Fluctuation in K resolution The source of free energy which drives fluctuations is believed To be  n 、  B 、  T. simulation appendix experiment

 s  0.1cm

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