Technical optimization of the ITER ICRH decoupling and matching system

The ITER ICRH load resilient matching system uses four 3 dB hybrid couplers. A prematching system is used near the antenna plug to reduce the line voltage up to the decoupling and matching system which is located in the Assembly Hall. The decoupling system placed just before the matching system is not only used to facilitate the matching of the antenna by reducing the mutual coupling effects between the different power sources but can also modulate the power transfer between them in order to actively control the array current spectrum while requesting the same forward power from all the generators [1]. The present decoupler layout appropriate for current drive phasings of the antenna array implies an active control of the relative forward power of the generators in case of heating phasings. It is presently difficult to use the decoupler layout appropriate for current drive phasings of the antenna array without active control of the relative forward power of the generators in case of heating phasings.