Extending the physics studied by ECE on ITER

The Electron Cyclotron Emission (ECE) diagnostic provides essential information for plasma operation and for establishing performance characteristics in ITER. Recently, the design of the ITER ECE diagnostic has been taken through the conceptual design review and now entering the detailed design phase [1, 2]. The baseline ECE system on ITER permits measurements of both the X- and O-mode radiation in the frequency range from 70 GHz up to 1 THz along two lines-of-sight, perpendicular and oblique at about 10 degrees, in the equatorial port. The system as planned meets the ITER measurement requirements. Nevertheless, there are several other mm-wave diagnostics in ITER, such as HFS, LFS and plasma position reflectometry, as well as Collective Thomson scattering system, whose transmission lines allow, in principle, additional measurements of parts of the ECE spectrum with upgrades of their back-ends, improvements in filtering and/or additional receivers. A discussion of whether and how supposedly to enable such ECE measurements is given here.