Parameterized modelling of mm-wave beam propagation of the ITER ECRH remote steering upper port launcher in CATIA

A 3D model has been developed in CATIA that is capable of accurate visualization of a mm-wave beam along the entire free-space section of a transmission line. This development has been applied to the design of the remote steering ECRH upper port launching system for ITER. Because the model uses parameterized equations to calculate the quasi-optical beam propagation, it can show the effects of a change of any of the transmission line components (location, orientation, or optical properties). Furthermore, it takes into account the effects the square waveguide has on the propagating beams as a function of its steered angle. The beam size at its target area inside the ITER plasma has proven to be a good indicator of the launcher's performance. It has also become clear that the 3D visualisation of the beam propagation in the structural design can result in a much more efficient use of the confined space inside each upper port plug—space that is also needed to locate sufficient neutron shielding and cooling structures, as well as to allow access for remote-handling tools.