ECRH/ECCD Experiments at 140 GHz on FTU Tokamak

Electron heating, profile control and current drive experiments are performed on FTU tokamak by using a four units EC system at 140, 2 MW total R.F. power. Each unit is composed by a gyrotron with 0.5 MW, 0.5 s pulse length capability, and an hybrid mirror/waveguide system allowing low-loss transmission of the millimeterwave power, with full control of the e.m. field polarization. FTU plasmas are illuminated from the low magnetic field side by four narrow gaussian beams, each one quasi-optically coupled to the correspondent waveguide. The launching system is capable of poloidal/toroidal beam steering through a set of tiltable in-vacuum mirrors, all placed outside the toroidal magnet. Up grading to 1 MW per line is under evaluation.