Progress in the new ECRH system for ASDEX Upgrade

A multi-frequency ECRH system with 4 gyrotrons, tunable in the range of 105-140 GHz, is currently under construction at ASDEX Upgrade with a total power of 4 MW and a pulse length of 10 s. A fast steerable launcher for feedback controlled deposition has been installed that allows for poloidal steering of 10/spl deg/ within 100 ms. Transmission line elements, such as corrugated waveguides, polarizer mirrors and vacuum windows, are designed to cope for this frequency band.