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Improved H-mode in JT-60U. Y. Sakamoto and the JT-60 team JAEA 12th Meeting of the ITPA Transport Physics Topical Group 7-10 May 2007, EPFL, Lausanne, Switzerland. Improved H-mode observed in JT-60U. Recent results of High p H-mode & RS H-mode.
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Improved H-mode in JT-60U Y. Sakamoto and the JT-60 team JAEA 12th Meeting of the ITPA Transport Physics Topical Group 7-10 May 2007, EPFL, Lausanne, Switzerland
Enhanced recycling in latter phase (t>23s) => ITB degraded Increased PNBI by stored energy FB sustained bN>2.3 => HH decreased bN>2.3 has been sustained for 28.6s • Steady current profile (q profile) much longer than tR was sustained 0.9MA/1.6T (t=18s) Ploss/PNBI=13.7% HH~1.1, bN~2.5 PNBI~8MW, bp~1.4 ne/nGW~0.48, tR~2s d~0.32, k~1.4 q95~3.3,fBS~43%
Co-rotation helps to form strong Te-ITB • Effects of toroidal rotation on ITB formation/sustainment were investigated by changing the combination of NBIs. • As co-rotation becomes smaller, central Te inside ITB was reduced. • When toroidal rotation was similar to that in the previous experiment without FSTs, Te profile became also similar. w/o FST E44092
type I grassy Grassy ELM frequency depends on toroidal rotation • Grassy ELM was obtained at low toroidal rotation freq. • WELM/Wped at 200Hz (grassy) is less than 1% • Pedestal performance is not changed. N.Oyama, PPCF2007
fBS~45% sustained for 5.8s under nearly full CD in weak shear plasma JT-60U Scenario: High bp ELMy H-mode (2.4T, 1MA, q95~4.5, d~0.5) Non inductive CD: PNBinj(co)=4.5MW & PNNBinj=4MW & Bootstrap High integrated performance towards ITER steady state scenario: bN~2.4 (bp~1.75), HHy2~1.0 (H89~2.3), fCD>90%(fBS~50%, fBD>40%), ne/nGW~50% PNB, NNB (MW) q bp, bN Vloop (V) Ti, Te (keV) Dadiv (a.u.) time (sec) r The duration was limited by NNB injection.
0.8MA/3.4T, q95~8.5, H98~1.8, N~1.4, p~2.1, fBS~70% sustained for ~8 s. Pressure profile control through toroidal rotation was successfully performed in real time control during 7-8 s. By utilizing new real time control logic, fBS~70% is sustained for 8 s
E45229: Ip=1MA, Bt0=3.7T Ti (keV) PEC (MW) PNB (MW) ECRF Ti (keV) Te (keV) ne (1019m-2) D (a.u.) Te (keV) time (s) Effect of EC heating on Ti-ITB PEC scanned stepwise (by 1 gyrotron), up and down. Even with 1 EC unit injection (0.78MW), Ti ITB changes. As PEC increases, Ti ITB decreases more. On the way back (decreasing PEC) Ti ITB recovers. Te does not increase much as PEC is increased. => electron transport could be influenced as that of ion is degraded.