Author/Authors :
Ikeda، نويسنده , , Y. and Kasugai، نويسنده , , A. and Takahashi، نويسنده , , K. and Kajiwara، نويسنده , , K. and Isayama، نويسنده , , A. and Ide، نويسنده , , S. and Terakado، نويسنده , , M. and Shinozaki، نويسنده , , S. and Yokokura، نويسنده , , K. and Anno، نويسنده , , K. and Shimono، نويسنده , , M. and Hiranai، نويسنده , , S. and Haga، نويسنده , , K. and Kajiyama، نويسنده , , A. and Ikeda، نويسنده , , Yu. and Moriyama، نويسنده , , S. and Tsuneoka، نويسنده , , M. and Sakamoto، نويسنده , , K. and Hamamatsu، نويسنده , , K. and Oikawa، نويسنده , , T. and Kamada، نويسنده , , Y. and Naito، نويسنده , , O. and Seki، نويسنده , , M. and Ushigusa، نويسنده , , K. and Imai، نويسنده , , T. and Yamamoto، نويسنده , , T. and Fujii، نويسنده , , T.، نويسنده ,
Abstract :
The 110 GHz 1 MW electron cyclotron range of frequency (ECRF) system was designed and constructed on JT-60U to locally heat and control the plasmas. The gyrotron has a diamond window to transmit RF power with Gaussian mode, which is easily transformed to HE11 mode for the transmission line of the corrugated waveguide. The second diamond window is installed at the inlet of the antenna for a vacuum seal between the transmission line and the JT-60U tokamak. The total length of the transmission line from the gyrotron to the antenna is about 60 m including nine meter bends, The antenna has a focusing mirror and a flat steerable one to focus and to control the RF beam angle mainly in the poloidal direction. In the initial operation, the power of PEC∼0.75 MW for 2 s was successfully injected into plasma when the gyrotron generated the power up to 1 MW. The total transmission efficiency from the gyrotron to the plasma was about 75%. A controllability of local electron heating with the deposition width of =15 cm was well demonstrated by using the steerable mirror. A large downshift in the deposition position was observed at the high Te plasma. Strong central electron heating was obtained from 2.2 to 6.6 keV for PEC∼0.75 MW, 0.3 s at the optimized polarization. An effective electron heating was also obtained up to ∼10 keV during EC injection for ∼1.6 s in the high βp H-mode plasma produced by NBI.
