Overview of the ITER-FEAT LH system

LH is considered to be used in ITER-FEAT steady-state scenario thanks to its highest current drive efficiency in the plasma outer part. The design of a 5 GHz, 20 MW CW LH system has been realised. That relies on a transmitter of 24 1-MW klystrons, and a circular oversized 60-m long transmission line feeding an antenna, based on the passive active multijunction concept. In order to have a high reliability, the power density is limited to 33 MW/m2. After the system description, the results of different studies are given: RF computation, launcher coupling properties, thermal analysis, mechanical stress caused by disruption, neutron activation, acceleration of electrons in the antenna near field.