Feasibility study of fast ion diagnosis in ITER by collective Thomson scattering, millimeter waves to CO2 laser

Here we report on a study of the feasibility of measuring the fast ion phase space distribution in the International Thermonuclear Experimental Reactor (ITER) by collective Thomson scattering (CTS). The study covers the full range of potential probe frequencies from gyrotron based millimeter waves to the infrared of the CO2 laser. It is assessed whether the systems can meet the ITER measurement requirements and which technological developments may be required. The relative merits of the systems are compared. The study reveals that a CTS system based on a 60 GHz probe has the highest diagnostic potential, and is the only system expected to be able to meet all the ITER fast ion measurement requirements with existing or near term technology. With modest additions this system may also provide measurements of the fuel ion ratio.