Design Concept and Thermal-Mechanical Analysis of the Optical Mirror (M3) for the ITER ECH Upper Launcher

The mirror M3 is a part of the in-vessel quasi-optical beam propagation system for the ITER electron cyclotron heating upper launcher (ECHUL). The millimeter waves are guided through fixed mirror sets (M1, M2, and M3) and the front steering mirror set (M4) to aim at the correct location in the plasma for suppression of the $q =3$ /2 and $q =2$ /1 NTMs. The design of the M3 shall guarantee the op...