Search for Suitable ICRF Operation Window for the Shaped H-mode Operation of KSTAR

KSTAR will try to achieve its 1(st) shaped H-mode plasma in 2010 campaign. The available power is limited by our plan for auxiliary heating system. Up to 2010, NBI with I MW, LHCD 0.5 MW, and ECH with 0.5 MW power will be prepared. To accomplish high beta plasma, TF magnetic field will be reduced to 2 T from rated field of 3.5 T. In this case the ECH contribution to H-mode power threshold requirement is ignorant because the 84 GHz frequency does not meet neither fundamental nor second harmonic resonance in the discharge area. Therefore the ICRF heating should carry out important roll to reach power threshold. The ICRF system of tunable frequency from 30 to 60 MHz will come with I MW power in 2010. To maximize the ICRF heating efficiency for H-mode purpose, we try to find suitable condition of ICRF heating parameters through the simulation using by TORIC(1) code. Optimizations of RF frequency, toroidal modes controllable by 4 current straps, and the minority concentration are performed. Possibilities of second harmonic heating of minority and the mode converted heating near resonance layer are also studied.