The 15 MW microwave generator and launcher of the lower hybrid current drive experiment on JET

The lower hybrid current drive experiment on JET (Joint European Torus), which is aimed at generating current in the plasma by launching a wave at 3.7 GHz into the torus, is described. The experiment required building a large high-power microwave generator and antenna. The generator can provide 15 MW for 10 s or 12 MW for 20 s. The power will be fed to a phased-array antenna consisting of 48 stainless steel modules assembled in an array of 384 waveguides. The antenna position will be controlled in real time in order to optimize the coupling to the plasma. The phasing between different modules can be set to vary the N/sub /// between 1.8 and 2.4.<<ETX>>