Author/Authors :
Saito، نويسنده , , K. and Takahashi، نويسنده , , C. and Yokota، نويسنده , , M. and Nomura، نويسنده , , G. and Shimpo، نويسنده , , F. and Seki، نويسنده , , T. and Kasahara، نويسنده , , H. and Kumazawa، نويسنده , , R. and Yoon، نويسنده , , J.S. and Kwak، نويسنده , , J.G. and Zhao، نويسنده , , Y. and Mutoh، نويسنده , , T. and Komori، نويسنده , , A.، نويسنده ,
Abstract :
In the Large Helical Device (LHD), long-pulse plasma experiments have been conducted using an ion cyclotron range of frequencies (ICRFs) heating system. Real-time impedance matching is necessary to keep injecting ICRF heating power into the plasma against the variation of the antenna impedance that changes gradually during a long-pulse plasma discharge. A feedback control system for the real-time impedance matching was constructed and utilized for long-pulse plasma discharges. As a component of the impedance matching device, liquid stub tuners were used. The reflected power ratio was reduced and kept sufficiently low by controlling the liquid heights during long-pulse plasma discharges, and the problem of the gradual increase in the reflected power was solved.
Keywords :
feedback control , Liquid stub tuner , LHD , Steady-state operation , ICRF heating
