ASIPP 研究生：章文扬 导师：高翔，李亚东 磁剪切对微观湍流作用机制的实验研究 December 8, 2009 Hefei, China

ASIPP Outline Introduction –Motivation –Outstanding works Experiment on HT-7 during LHCD – experiment Open questions References

ASIPP Electron Thermal Transport is Anomalous All operational modes of tokamaks have exhibited anomalous electron thermal transport. There is evidence that electron temperature profiles are stiff in tokamaks. Possible theoretical candidates include: –Trapped Electron Mode (and ITG with trapped electrons) –Electron Temperature Gradient Mode –Magnetic Flutter –Something other than Turbulence

ASIPP Reducing  e in Burning Plasmas Various transport channels behave differently in forming ITBs. In most cases, Electron heat ITBs are formed by localized electron heating on RS plasmas [cf., JT-60U high triangularity, PS plasmas] The following stabilization mechanisms are likely to be ineffective in BP: –Density peaking for ITG, ETG,… –High Te/Ti for ETG (High Ti/Te for ITG ) –NBI-driven Flow Shear (?) q - profile control (eg., RS) remains effective in reducing electron heat transport in Burning Plasmas: –Precession reversal of trapped particles –Suppression of ETG streamers –Stabilization of NTM

ASIPP TORE SUPRA:(a) The reversed current profile is the main factor leading to stabilization of the TEMs. (b) ETG overcomes the stabilizing effect of the negative magnetic shear on the ETG branch. TORE SUPRA: I p = 0.7 MA, B T = 3.9 T, n e (0) = 2.5 × m −3 C Fourment et al Plasma Phys. Control. Fusion 45

ASIPP NSTX:ITB with HHFW (negative magnetic shear) E. Mazzucato Nucl. Fusion 49 (2009)

ASIPP Outline Introduction –Motivation –Outstanding works Experiment on HT-7 during LHCD – experiment Open questions References

ASIPP HT-7 CO2 collective scattering system

ASIPP k  k   s  s 12cm -1 18cm -1 20cm -1 24cm -1 Te:1.2keV  s :1.86mm Te:0.9keV  s :1.61mm Te:0.6keV  s :1.31mm Te:0.45keV  s :1.14mm Te:0.3keV  s :0.93mm ITER Physics Basis 2007 Chapter2 Plasma Confinement and transport E.J. Doyle et al Drift wave turbulence scales

ASIPP Plasma current:120kA,150kA 2008 Experiment during LHCD LHW power:50kW---650kW

ASIPP Ohmic normalized fluctuation level as a function of LHW power Plasma current:120kAPlasma current:150kA The stability of the mode in TEM and TEM/ETG range may be related to q profile.

ASIPP Outline Introduction –Motivation –Outstanding works Experiment on HT-7 during LHCD – experiment Open questions References

ASIPP Open questions Stiffness as a possible feature for characterising of ETGs? –Create condition where TEM stabilized while ETG should be active. Experimental conditions for e-ITBs –Low density required? –Clear reversed magnetic shear required, not ExB shear True for pur e-ITBs, no trigger required ? For e-ITBs in parallel with ion -ITBs also ? only condition ? –Why e-ITBs do not form in parallel with ion-ITBs in some devices ? No direct experimental evidence of ETG dominating electron heat transport

ASIPP Outline Introduction –Motivation –Outstanding works Experiment on HT-7 during LHCD – experiment Open questions References

ASIPP References [1] E J Doyle et al 2007 Nucl. Fusion [2] Wolf R C et al 2001 Nucl. Fusion [3] Baranov Y F et al 2004 Plasma Phys. Control. Fusion [4] Jiquan Li and Y Kishimoto 2002 Plasma Phys. Control. Fusion 44 A479 [5] Rhodes T L et al 2006 Rev. Sci. Instrum E 922 [6] Gusakov E Z et al 2006 Plasma Phys. Control. Fusion 48 A 371-6s [7] Hennequin P et al 2004 Plasma Phys. Control. Fusion 46 B121 [8] Mazzucato E et al 2008 Phys. Rev. Lett [9] Rhodes T L et al 2007 Plasma Phys. Control. Fusion 49 B183 [10] E Mazzucato 2009 Nucl. Fusion [11] Li Y D et al 2004 Plasma Sci. Technol [12] Devynck P 1997 Plasma Phys. Control. Fusion –1371 [13] Litaudon X et al 2001 Plasma Phys. Control. Fusion [14] Gao X et al 2008 Plasma Phys. Control. Fusion [15] lin S Y et al 2006 Plasma science & Technology Vol 8 No.3 [16] C Fourment 2003 Plasma Phys. Control. Fusion –250 [17] Koide Y et al 1998 Plasma Phys.Control.Fusion

ASIPP Thanks for your attention!