Typical RF system layout, showing arrangement of power tubes, transmission lines, and launcher port plugs

All the radio-frequency systems follow a common design approach using a shielded equatorial port plug housing the wave launcher attached at the back to the vessel port extension, and looking from the thermal and shielding points of view like the surrounding blanket and vessel. Transmission lines link the port plugs to power tubes located outside the torus hall.

EC RF Heating Equatorial Port

The status of development of the power tubes is different for the three systems. The 170 GHz, continuous wave (CW), 1 MW, 50% efficiency gyrotron development programme for the EC system is still some way from meeting ITER specification. The best results achieved to date (in the continuing development programme) at this frequency are: 20s pulse length, 0.9 MW and 43% efficiency. Steady state and efficiencies above 50% have been acheived at lower power levels. For IC, an industrial study has shown that a source fulfilling ITER specification (2 MW-CW-40/60MHz) could be constructed using existing tetrodes, although an upgrade of a current tube would lead to a more cost-effective source. There are no detailed studies of a 1MW-CW-5 GHz klystrons needed for LH systems.

More information can be found in the ITER Technical Basis .