ITER divertor operation is dominated by the necessity to exhaust around 200MW power via the scrape-off layer. A large fraction of the input power must be irradiated by the impurities either intrinsic or seeded. It is important that the radiation source be well distributed over the entire divertor plasma. The plasma detachment at the divertor target should be precisely adjusted as to enable a partially attached operating, that is detached near the separatrix strike point and attached further out in the scrape-off layer. To provide information on key fenomena which may limit the divertor performance is the challenging task for diagnostics in ITER.

The reliable Tc, nc profile measurements in the divertor upstream (near X-point) and downstream (divertor bottom) regions address the highly promising Thomson scattering diagnostics. The high resolution time-of-flight LIDAR Thomson scattering for the X-point and the conventional Thomson scattering technique for the divertor leg fit the reference divertor configuration with minimal impact on ITER design.