THE ASDEX UPGRADE ICRH ANTENNA

The ICRH antenna, of which four are installed in ASDEX Upgrade, is designed to operate over a wide range of frequencies (30-80 MHz). Each antenna consists of two toroidally spaced loops, which can be operated in-phase or out-of-phase. The loops are folded in the poloidal direction such that even at the high frequency of 80 MHz the current varies in the poloidal direction by only 20%. The mechanical design is flexible: the major components of the antenna can be reutilized when the antenna is adapted to a single-null, double-null or limiter plasma configuration.